Hey guys!
New member here. I'm looking at purchasing a GS500 from facebook marketplace. It's a 96 and looks pretty good. The issue it has is that when you add throttle the bike either dies outright or has a rev hang for a couple seconds. The actual idle sounds pretty good.
I know it will need a little work but i'm actually looking for something I can work on a little during the winter and I heard these bikes are a great place to start. By searching here it sounds like the most probable problem might be a vacuum leak?
He has it listed as 900 obo. I was wondering how low you think a fair offer would be seeing as it'd not currently rideable. Also, are there any things I could do when I go check it out to make sure the problem is nothing more nefarious? I'm not sure if it would be appropriate to be spraying carb cleaner on his carbs before I buy the thing to confirm a vacuum leak or not.
Thanks in advance guys.
-Alex
Do a compression test. It should be at least 140psi both cylinders and both close to one another.
While lots of people report problems like this and others on this forum suggest it may be a vacuum leak, the truth is that vacuum leaks are very common and can cause a wide array of symptoms. So basically any running problem with a GS500 might be a vacuum leak, but it might also be a dozen other things. I would rule out a very expensive repair first by doing the compression test.
You can sort out a lot of potential issues by going through the carbs and replacing all of the o-rings, intake boot o-rings, inspect the diaphragms and replace if necessary, undo any modifications, etc. But that's kind of labor intensive and it's basically impossible to diagnose that this will be the eventual solution on a bike you are considering buying.
FWIW my GS had basically this same kind of symptom when I bought it, and I paid $800 for it about 3.5 years ago. Then I had to do a top end rebuild and replace the carburetors plus a dozen other small things before it was dependable. I probably have close to $2500 in it by now. In the end I would have been a lot better off buying one that had 1/4 the miles on it and ran right from day one even if it was twice the price.
If it is in basically mint condition besides this running issue and you have another $1K available to invest in case it needs hard engine work, then $900 is probably a fair price. If it's a beater bike and would not be worth more than $1500 if it was running 100% then I wouldn't pay more than salvage money for it... like $300-400.
Ok awesome, I'll make sure to ask if I can do a compression test. I don't mind doing some carb work but I definitely don't want to bite off more than I can chew. Do you think if the compression checks out than the problem should be at least something I can handle?
If compression checks out then that rules out very expensive repairs. Carb cleanup and refreshing is easy and pretty cheap, if that's what the problem turns out to be. Otherwise ignition, which is also cheap. Basically everything that could likely be wrong is cheap and easy to do besides rings and valve seats. But I would budget a couple hundred dollars just in case you have to get new intake boots ($40/ea) or find a used OEM airbox, etc.
BTW I don't know where you are located or how much of a hurry you are in to get a GS500, but they pop up all the time in excellent condition without these issues for under $1500 in my area. You just have to be patient. Just depends on whether you want a project or something to use.
Quote from: mr72 on January 07, 2020, 12:21:13 PM
BTW I don't know where you are located or how much of a hurry you are in to get a GS500, but they pop up all the time in excellent condition without these issues for under $1500 in my area. You just have to be patient. Just depends on whether you want a project or something to use.
I would actually prefer something that takes a little work to get on the road. I want to work on it with my son so he can learn to be more mechanically inclined than I was.
Its also a lot easier to to smooth over the wife on dropping 600 on a bike instead of over a grand, even if eventually the costs even out.
Same as me. I'm not happy if I buy a bike and it just works. I need to feel like I've somehow made it better. Considering mine came with a bodged carburettor, incorrectly timed exhaust camshaft, I'd say I've done well.
Welp, looks like I'm a real member now.
Step one is cleaning this gas tank it's really bad. I'm not sure how it was even idling and revving on neutral. Hoping it's a case of a rusty tank gumming up the carbs.
Probably not. Rust in the tank can and does cause problems and clogged carbs cause issues for sure but most of that manifests as low power or bogging and stalling at high revs and under load. Seriously check the compression.
IDK about cleaning and fixing a rusted tank, but the internet is full of experts on that. But you can sort the carbs with details on my blog post from a couple of years ago: https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html
You can run it from a remote fuel tank. You have to disconnect the fuel lines anyway to pull the tank, so while you work out the tank I'd grab any old cheap lawnmower fuel tank and hook it up with like a pint of fuel to evaluate the carbs condition.
Got it! I did check the compression before purchasing. Both cylinders were right on at 150.
Also when checking it out I found out a little more about the running issue. It will rev all day in neutral. It's only when you try and take off in gear that it bogs down. Sounds like regardless I will need to go through everything like in that blog post. Do you happen to have an updated link to pin point exactly what o rings, needle valve and pilot jet to purchase?
Also I think there may be an aftermarket needle in there. It's a sharper looking one with a C clamp at the top. Is this the part that can cause a lot of issues?
A couple of things I noticed after reading your post and looking at these carbs.
The mixture was way off. Almost 5 turns on each screw. Both needle valve seat o rings have corrosion and the cavity they sit in has residue in there
One of the seats did not look sealed at all. Floats were also a tiny bit off.
All that leaves me optimistic towards a simple carb job doing the trick.
Sounds great. American market bikes has aluminum needles with only one groove. Aftermarket needles are often stainless steel with 4 or 5 notches for the circlip. If it has dynajet needles and jets I'd advise switching back to stock.
I don't have any updated info about o rings. A k&l carb kit has all of the o rings and float valves and seats. Cheap too.
Quote from: mr72 on January 12, 2020, 12:29:51 PM
Sounds great. American market bikes has aluminum needles with only one groove. Aftermarket needles are often stainless steel with 4 or 5 notches for the circlip. If it has dynajet needles and jets I'd advise switching back to stock.
I don't have any updated info about o rings. A k&l carb kit has all of the o rings and float valves and seats. Cheap too.
Does this kit look ok? It seems a little pricier than you suggest in your article.
https://www.bikebandit.com/aftermarket-parts/motorcycle-fuel-and-air/carb-kits-parts-accessories/k-l-economy-carburetor-repair-kit/p/18639?m=139235
Bike Bandit will be among the most expensive places. You can run the gamut of price/quality/trust from ebay, example:
https://www.ebay.com/itm/2X-Carburetor-carb-Repair-Rebuild-Kit-SUZUKI-1989-2000-GS500-GS-500-GS500E-US/283567149274?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Dd41e4a5751734d8b8f5fad2408af3e58%26pid%3D100005%26rk%3D2%26rkt%3D12%26mehot%3Dco%26sd%3D382889026580%26itm%3D283567149274%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851
What's wrong with the link in my blog?
http://www.thisoldtractor.com/for_sale_dr350_orings.html
you can get the o-rings one at a time there and then just order float valves and seats from ebay or Amazon. That way you can get viton o-rings for all of the fuel-exposed areas. And they are really cheap this way. Or you can buy a cheap pair of rebuild kits from eBay and select viton o-rings from thisoldtractor.com (pilot needle, float seat, etc.) to supplement. Still whole enchilada under $40 for both sides any way you go for it. While you have it apart, good idea to go ahead and replace the intake boot o-rings. They are probably shot.
Quote from: mr72 on January 13, 2020, 07:42:13 AM
Bike Bandit will be among the most expensive places. You can run the gamut of price/quality/trust from ebay, example:
https://www.ebay.com/itm/2X-Carburetor-carb-Repair-Rebuild-Kit-SUZUKI-1989-2000-GS500-GS-500-GS500E-US/283567149274?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Dd41e4a5751734d8b8f5fad2408af3e58%26pid%3D100005%26rk%3D2%26rkt%3D12%26mehot%3Dco%26sd%3D382889026580%26itm%3D283567149274%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851
What's wrong with the link in my blog?
http://www.thisoldtractor.com/for_sale_dr350_orings.html
you can get the o-rings one at a time there and then just order float valves and seats from ebay or Amazon. That way you can get viton o-rings for all of the fuel-exposed areas. And they are really cheap this way. Or you can buy a cheap pair of rebuild kits from eBay and select viton o-rings from thisoldtractor.com (pilot needle, float seat, etc.) to supplement. Still whole enchilada under $40 for both sides any way you go for it. While you have it apart, good idea to go ahead and replace the intake boot o-rings. They are probably shot.
Ok sounds good, does that site not have the float bowl gaskets or am I missing that?
I haven't ordered them from that site. All of even the cheapest kits have float bowl gaskets. I haven't replaced mine. One leaks, so one of these days, I'll replace it.
Love seeing me a resurrected GS! Any pics of this?? Rusty tank,... I've found dawn w vinegar 50/50 will clean it up nicely.
Hope to read more of your GS experience! :woohoo:
Quote from: cbrfxr67 on January 13, 2020, 10:38:18 AM
Love seeing me a resurrected GS! Any pics of this?? Rusty tank,... I've found dawn w vinegar 50/50 will clean it up nicely.
Hope to read more of your GS experience! :woohoo:
Once I get through these impossible security questions that don't have answers i'll be able to post more from my phone with pics!
Could you give me a quick rundown of your process? I tried vinegar but wasn't able to seal the tank holes well enough, and while I was able to shake out a lot of the rust flakes leaving it sitting left me with some surface rust since it leaked out eventually. How do you plug the holes?
ALSO, while going through the carbs they don't look too bad. I wonder if the problem is actually something silly like the kickstand safety switch. I feel like that would make a lot of sense since you can rev all day in neutral but dies when you try and take off in gear. Nevertheless I ordered those O rings and will be cleaning and replacing, setting back to spec, hopefully getting that tank decent and seeing what happens this weekend!
i just put some vacuum caps on the 'holes.' Or just turn it upside down if your cap doesnt leak. I don't really measure it too scientifically. Dump vinegar in, squeeze off a load of dawn and fill it up with water and let it sit for a couple hours. Dump enough out to where I can handle it and shake the shazam out of it. I drop die grinder wire brushes in it while I'm shaking it. Some people like nuts and bolts, maybe a chain :dunno_black: but bolts etc are too hard to get out and I don't want any dents from a chain. Rinse and repeat.
Here's a gsxr1000 tank I did a few months back,..clicky for bigger
(https://i.ibb.co/yPKzZR1/68751554-10220012837374536-2638258703236595712-o.jpg)
after
(https://i.ibb.co/k8WBnr5/68620435-10220020209758841-6675918464198115328-o.jpg)
I think I did it three times. It probably would have kept cleaning up the more I did it but I felt this was good enough. Dawn & Vinegar was recommended to me by a guy that takes on a local dealership's work from customers who bring them old bikes. They don't want to mess with any of the old stuff so they send it all to him.
Quote from: aconti2 on January 14, 2020, 07:14:20 AM
Could you give me a quick rundown of your process? I tried vinegar but wasn't able to seal the tank holes well enough, and while I was able to shake out a lot of the rust flakes leaving it sitting left me with some surface rust since it leaked out eventually. How do you plug the holes?[/quote
Just to be clear, are you saying there are RUST HOLES in the tank? or talking about sealing off the petcock hole?
Quote
ALSO, while going through the carbs they don't look too bad. I wonder if the problem is actually something silly like the kickstand safety switch. I feel like that would make a lot of sense since you can rev all day in neutral but dies when you try and take off in gear.
So no matter what it "just dies" if you release the clutch? Tried this with the bike on a center stand? I mean, this is very dangerous so be quite careful, but if the rear tire is in the air you should be able to release the clutch with it in gear and the side stand up and ensure the safety interlocks are not malfunctioning. Otherwise you can hotwire the clutch switch and be sure that that is not causing the problem.
Side stand switch has a relay and also there's a diode pack to do the switch logic between the side stand, neutral and clutch switches. Get a wiring diagram and study it. You can easily jumper the connector to the side stand switch to make it think side stand is always up.
You need to determine whether it's that it dies when under load or if it dies when clutch out and in gear and side stand up.
Sorry, petcock and gas cap holes yes.
I will perform that test when I reassemble. I didn't feel like messing with it too much because I knew I wanted to get that nasty gas out of there and go through things right away. I'll report back and maybe take a video if the problem persists.
Another fun thing I found out while studying how to assemble everything is that this bike is missing the drain hose from the bottom of the airbox, the tank drain hose, and the hose that connects to the top of the carbs.
Would any of these cause an issue while testing since they all essentially lead to nothing? Also anyone know what kind of hose I could need to track down?
Hoping I can assemble and test tomorrow as long as my O rings come in the mail today!
Also I am finally FREE of those dang questions.
Mine is missing two out of three of those. Big thing is the vent hose for the carbs needs to NOT be facing forward otherwise you will have stalling at speed.
Any hose that will fit is fine. Somewhere poking around the forums is a hose routing diagram, I'm too lazy to find it but you probably are not.
Quote from: mr72 on January 17, 2020, 06:53:06 AM
Mine is missing two out of three of those. Big thing is the vent hose for the carbs needs to NOT be facing forward otherwise you will have stalling at speed.
Any hose that will fit is fine. Somewhere poking around the forums is a hose routing diagram, I'm too lazy to find it but you probably are not.
Awesome, that's all I needed to know! You are correct, I found this amazing resource to fool proof putting the lines back on. Trying to save all my questions for things I can't seem to find on my own.
http://www.bbburma.net/FuelHoseRouting.htm
Got her all together again today!.......and no dice.
First thing I noticed is my neutral light is no one longer working.
When trying to start it weakly tries to turn over a couple times and then turns to battery clicking. Before I took it apart it started up just fine.
Would there be something I disconnected that would mess with the neutral light AND starting or am I looking at a compounding issue. Trying to start with the clutch in of course.
Quote from: aconti2 on January 18, 2020, 07:20:17 PM
First thing I noticed is my neutral light is no one longer working.
When trying to start it weakly tries to turn over a couple times and then turns to battery clicking. Before I took it apart it started up just fine.
The "click, click, click, click" usually = low battery in my experience. If you have a tender, charge it overnight and that may be that (hopefully).
I wouldn't be too concerned about the neutral light until the battery is ruled out. What about the oil light? On when you are trying to start the bike?
Quote from: brucedavidculver on January 18, 2020, 11:15:21 PM
Quote from: aconti2 on January 18, 2020, 07:20:17 PM
First thing I noticed is my neutral light is no one longer working.
When trying to start it weakly tries to turn over a couple times and then turns to battery clicking. Before I took it apart it started up just fine.
The "click, click, click, click" usually = low battery in my experience. If you have a tender, charge it overnight and that may be that (hopefully).
I wouldn't be too concerned about the neutral light until the battery is ruled out. What about the oil light? On when you are trying to start the bike?
Oil light turns on and I believe it would turn off temporarily while it was cranking. Also I'll add that it was below freezing last night so I'm sure that didnt help me. When I bought the bike initially it fired right up but it was in the 60s. Dude said he bought a new battery for it so I guess I'm off to get a charger.
Just went over to Walmart and picked up a battery tender junior. Only getting the blinking red light :icon_confused:
Could a battery that just worked last week be so shot it cant be charged?
Quote from: aconti2 on January 19, 2020, 09:11:04 AM
Just went over to Walmart and picked up a battery tender junior. Only getting the blinking red light :icon_confused:
Could a battery that just worked last week be so shot it cant be charged?
It depends on what the dude's version of "new" is I suppose. Everything has to die at some point... and rarely conveniently... lol
I assume it is not a wet cell since its new? If it is, check the water levels as well. Low water would keep it from accepting a charge.
I was only curios about the oil light because that bulb shares a wire with the neutral bulb (if my memory serves me). If they were both dead I would be more concerned about it being electrical.... plus "click click click" should mean that juice is getting where it needs to go... just not enough. Also, it's easy to pull the bulbs out from the back and switch them... just to rule out the bulb itself or a connection at the gauge.
My $$$ is still on the battery.
It's a sealed battery so no water level I don't think.
Anyways I brought it to advanced auto parts. Guy said it was reading 11 volts which to my understanding is pretty dead? He said he would through it on their charger and let me know what happens.
:cry: :cry: :cry:
Ok, Advanced auto parts got some juice in the battery. You were right about the nuetral light it came back on. Left it on the tender overnight and we'll see what happens when the wife gets home!
My bet is you have a dead cell. These batteries have 1.2v cells in series. One bad cell will result in a battery that is only 12.0 v fully charged and 10.8v when low. 12.0 will start the bike but it falls below that quickly making it seem like it only holds a charge for a minute. You can get an AGM battery at Walmart for $40. Not worth the hassle of debugging to much IMHO.
Quote from: mr72 on January 20, 2020, 06:26:02 AM
My bet is you have a dead cell. These batteries have 1.2v cells in series. One bad cell will result in a battery that is only 12.0 v fully charged and 10.8v when low. 12.0 will start the bike but it falls below that quickly making it seem like it only holds a charge for a minute. You can get an AGM battery at Walmart for $40. Not worth the hassle of debugging to much IMHO.
Battery read 12.5 at AAP and took a few good hours to read as 80% charged on my tender so I'm optimistic it charged to a point well north of that.
Ok guys, got the GS all fired up. She now will also run! Just not very well.
So here's the issue.
If I set the idle to run normally the bike would alternate between functioning normally and dying.
If I set the idle higher it fluctuates between very high idle and regular functioning.
It basically feels like my bike has two minds that its switching back and forth between. Any thoughts? Tests I can do?
I forgot to add that the engine power comes and goes with these surges. When its low it was struggling to not stall going up the hill from my house.
That all sounds like the slides are not moving up and down as they should, could be due to a vacuum leak, torn diaphragm, other issues. Vacuum leak means low vacuum and slide doesn't come up when it should, bike stalls or fails to accelerate. Vacuum leak is restored briefly and suddenly the slides come up and it races the engine, only to then die once the vac leak resumes. The slides are pulled up by vacuum applied to the diaphragm so leaking, poorly seated diaphragm, or one damaged by carb cleaner or torn, will cause this. Missing or leaking vacuum caps on the carbs are next most likely, followed by missing o-rings under the vacuum caps, and then intake boot o-rings are bad or intake boots leaking. That's most of the places for a vacuum leak to be.
There's never been a battery that gets better with age!!!
A good healthy battery is required for this (any) bike, and you will only give yourself heartache trying to get by with one that's on the way out. Yours is.
You might be able to put off replacement for a little while, but believe me, it'll get you in the end... Probably 100 miles from home, deserted, on a dark cold rainy night when you've just hurt your back.
It took me 40 years to learn this simple lesson, but now, whenever any battery shows under normal voltage (under 12.5 - ish) I just go and buy another one.
Thanks Mr72, I did find your post "demystifying vacuum leaks" in my search and noticed that your description pretty much matched my experience.
I looked up some examples of what bad intake boots look like and I realized I may have been too kind in my assessment of mine. Diaphrams looked great and I replaced all of those other O rings at your suggestion.
I have read a lot on this forum about leaking vacuum ports. Whats the solution to this, new top cover, new rubber caps?
UPDATE
I replaced the old intake boots and my crazy out of control idle swing went away. But now I have another issue. Here's what happened.
Started the bike. It fired right up. Revs quickly climbed to 5k with the choke fully on. Backed off the choke a little and then the idle dropped nicely and bike held steady.
Took off, wow! Bike had great power and I ran through the gears no problem. It felt just like my old motorcycle I used to have did when it was working properly.
This only lasted about a minute. After that my idle dropped below 1k. Bike would stall and bog with throttle. Idle screw did not seem to change anything and putting full choke back on only brought the revs back up to around 2k.
Any thoughts? It was so sudden. Could it be that battery we know is on it's way out?
Try again without turning off the choke all the way until you've been underway for like 5 minutes. Otherwise this could still be w vacuum leak causing the petcock to not stay open, so try running on prime if it happens again and see if that fixes it. Could also be sticking float needle valves, float level too low, other fuel delivery problem.
My bet is you just got in too much of a hurry to turn the choke off. These bikes are very cold natured.
I tried prime, no luck. Tried restarting with choke full on. No luck. Nothing I did could recover the idle I had when I first fired it up. It just wanted to die with any throttle after that.
Such a tease because it felt really solid. I'm at least really happy to have solved the large vacuum leak causing it to go haywire. I think you're right that I'm dealing with a more straightforward fuel problem. Feels like I'm getting close.
I've got a clear tube lying around I'll do the float height test when I get home and maybe try bringing the mixture screws to 3 turns instead of 2 1/2. I'm most bewildered by why it started up so good then instantly wouldn't stay alive.
don't mess with the pilot needle adjustment. adjust it correctly, which means you need to ride it until it's fully warmed up and then adjust for fastest idle. don't guess with that. If it's too rich right now you will just make it worse. I can't remember if you replaced the o-rings on the pilot needles, but if you didn't, then they could be leaking causing it to always run way too rich at idle.
could be it's flooding, could be stuck open float needles. Mine usually won't start with full choke once it's been at least partly warmed up. Solve one thing at a time. Don't screw around with the idle mixture until you can get it running under load and get the bike to warm up correctly. You can always nurse the idle once you get the carbs working right in all other stages and then dial the idle in right once you fix everything else.
Good call checking the float height. It's either not getting enough fuel, getting a lot of extra air via a vacuum leak, or getting way too much fuel. The plugs can help you figure out what but the truth is you can set it up to be way too rich at idle and then it'll be lean under load if you have a vacuum leak. So you HAVE to fix all vacuum leaks before you can even assess mixture. And float level can affect dynamic mixture (that is, mixture changes over time dependent on load) so you HAVE to sort that before you can evaluate the mixture. Once you know that is 100%, and I mean by replacing o-rings and vacuum caps etc. not by spraying something on the carbs and guessing, only then can you begin to figure out the mixture. If you have stock airbox and exhaust then a 122.5 or 125 main jet and 40 pilot with 2 turns out on the pilot mixture will get it in the ballpark and then all there is to do is adjust idle mixture. If it's not running right under those conditions, then vacuum, slides/needles/diaphragms, carb assembly, float level, float needles are the likely causes.
Ok sounds good!
I'll check the float height first and if that doesn't show anything i'll go through that carburetor again.
That would be cool if it was just float height. Maybe that crazy vacuum leak I had before allowed fuel in and that minute I was running it last night just combusted anything I had left over in the engine and once it needed more the float height didn't allow it. That's my optimistic pipe dream. :icon_lol:
Glad I started this in the dead of winter and not in nice weather.
well the vacuum leak caused two problems:
1. insufficient vacuum pressure to pull the slides up
2. air getting in without going over the jet
so it winds up making it run really lean, and then barely at all.
A vac leak anywhere will have this same effect. top of the carbs, leaking in the vac line going to the petcock, seal of the diaphragm, throttle shafts, you name it. air gets sucked in and that air is not going past the jets so it has no extra fuel to match. thus, vacuum leak causes lean running. And then too often we skip the step of finding and fixing the vacuum leak and instead try to compensate by tuning it way too rich, but then it is only running correctly when under WOT and high revs, but it will be untuneable at idle or low throttle openings.
the theory on the float level is that you either had the floats too low, so you starved it of fuel before it could refill, or you had the floats too high, so it flooded once the choke is turned off and not consuming all the extra fuel.
So my tube didn't fit snugly around the drain hose like in the video I saw so I wasn't able to check the float height on the bike.
Tried to start it up just to see what would happen as it sat for a day. Just barely started, died, then wouldn't start, then lights started dimming. Hooked up the battery to the tender again, too low to charge.
Battery is toast like you guys were telling me. Not going to do anything until I get a new one. However I am a little over budget this month so i'm going to give it a slight pause. I could use a mental break as well.
I also forgot to mention previously I got the infamous oil leak underneath the side stand. I took off the cover to the front sprocket and HOLY JESUS there was about an inch thick layer of much and wax and dirt. Disgusting, but the "leak" went away instantly!
New battery, nothing changed. Bike didnt even want to start. New plugs and the bike roared to life. Old plugs were completely carbon fouled.
I let it warm up for a few minutes and got the idle nice and steady, everything sounded real good. Tried to take off and everything that happened before happened again. Checked the new plugs and they are completely black and smell like gas.
So obviously I am running super rich to the point where the sparks start to fail. Cant find too much on this other than a blocked air filter or a leaking needle valve seat. Next step may be to replace those seats... :dunno_black:
Or more likely you need new rings and or valve guides.
Quote from: Joolstacho on February 20, 2020, 11:50:29 PM
Or more likely you need new rings and or valve guides.
Oh boy...would the compression test not have ruled that out?
black plugs and wet -> too rich. That's when you start the bike, not when it's warmed up, so we're not talking about a mixture problem likely.
Consider what would make it super too rich when first starting up regardless of throttle. Can't be the main jets because the needles are in the jets so (little or) no fuel coming in there. So whatever is happening, is happening on pilot.
- float level way too high, caused by it being adjusted wrong, leaking/bad needle valves, seats, o-rings, etc.
- incorrect pilot mixture, in this case most likely bad/missing pilot needle o-rings or incorrectly assembled pilot needle setup (spring/washer/o-ring wrong order, didn't pick out the old o-ring before installing a new one, etc.)
When my bike had bent valves and bad rings, it would only run when cold and then once warmed up, it would not run below about 5K rpm and required constant throttle to keep it running. It ran fine as long as you revved the crap out of it. Shop originally thought it was leaking float needle valves but they were wrong.
Ok thanks guys.
Pilot screws went through carefully, o rings replaced and I used the diagram to put it in the correct order.
I'm going to to replace the needle and seat and triple check the float height. Worth giving a shot and eliminating a carb problem before moving to the engine.
Quick question, should I be tapping the seat into place gently with a hammer or use strong finger pressure?
Update.
After checking the oil I saw a good amount of fuel had gotten inside. I decided to change my needle and seats, triple checked everything on the carb and made sure it was perfect.
Upon starting the bike again I had the same problem, except this time the plugs weren't fouling with fuel, they were being covered in what looked like oil. They were stinking like fuel before because I had fuel in my oil.
Decided to check the compression again to rule out a mistake there. I found my mistake. I did the test at the seller's house with one plug off at a time. With both plugs out and grounded I got barely more than 130 psi in each side. Compression tester also got some oil on it from the cranks just to do the test.
Wasnt sure what to do at first. I'm not terribly afraid of the job but with tools and parts it was going to be pricey. I have a mechanic friend I was talking to about this and he said itd be super easy. I said hey what if I just pull everything and hand you the head and pistons? So that's just what I did!
Removing everything turned out to be a piece of cake. I just followed the top end rebuild video on youtube step by step. Everything slides out nicely right in the frame.
Upon receiving the head he could tell right away the valves were leaking. He pulled the seals and said they just fell apart. Valves are still in good shape.He will also be doing a ring job.
I ordered new gaskets and orings (including copper washers) for when I reassemble so I think that just about rules out any oil leaks that could be occurring inside the engine.
I'm spending more than I hoped but this is turning out to be such a fun and rewarding experience. I finally understand the basics of engines just by taking everything apart and seeing how it all works. It was a super cool experience taking everything apart. I used to think this kind of stuff was beyond me. I was cringing a bit just reading my posts at the beginning of this thread! I'll keep you guys updated.
I also forgot to mention when I could get it to rev I recorded the exhaust and could clearly see blue smoke. Here are some pics!
https://ibb.co/7W12shK
https://ibb.co/b1BGqVQ
https://ibb.co/4fJnTkR
My experience with compressions tests. I was worried when my gs only tested at 120 and 116, considering the min spec is 140, but hey guess what, it makes no freaking difference. The front right exhaust was a little bit loose and getting looser started at 06mm but gradually went to .1 however she has stayed there. The problem I was having was a faulty carb slide press fit piece that had come loose. New carb fixed that and she's been running really well ever since.
So seeing as I had the compression test kit, I tested an almost new S40 Suzuki and it too was testing 125 when it should have been 140 at the lowest, and goes like the proverbial rocket.
Make of that what you will.
Quote from: user11235813 on May 13, 2020, 01:08:29 AM
My experience with compressions tests. I was worried when my gs only tested at 120 and 116, considering the min spec is 140, but hey guess what, it makes no freaking difference. The front right exhaust was a little bit loose and getting looser started at 06mm but gradually went to .1 however she has stayed there. The problem I was having was a faulty carb slide press fit piece that had come loose. New carb fixed that and she's been running really well ever since.
So seeing as I had the compression test kit, I tested an almost new S40 Suzuki and it too was testing 125 when it should have been 140 at the lowest, and goes like the proverbial rocket.
Make of that what you will.
Noted, I'm not so worried about the compression as I am the plugs getting wet with oil and blue smoke coming out the back. Though I am resigned to the fact that maybe I'm overreacting but a fun project none the less and I need it right now.
Valve seals can be checked with engine in frame. In fact its best checked that way because by the time you take everything apart you've destroyed the evidence. Remove exhaust and carbs. Remove spark plugs. Turn over motor looking at valve stems. And for good measure clean them with a Q tip. Then turn it over a few times. Good seal = no oily stems.
Cool.
Buddha.
Quote from: The Buddha on May 13, 2020, 07:45:27 AM
Valve seals can be checked with engine in frame. In fact its best checked that way because by the time you take everything apart you've destroyed the evidence. Remove exhaust and carbs. Remove spark plugs. Turn over motor looking at valve stems. And for good measure clean them with a Q tip. Then turn it over a few times. Good seal = no oily stems.
Cool.
Buddha.
Yeah I realized I probably could have gotten away with a lot less but it's too late now. Everything is going to be gone through. The way I see it I can no bank on that engine lasting a long while and it can stay in the family.
IMHO diagnosing stuff is an art, a fast fast fast disappearing art.
Doing sheite is a lot easier.
Its easier to slap chit up and "weld it all together" That's why we have stupid retarded a$$$ stretched busas. and bobbers made from 1 and 2 cyl standards and café racers made out of GS850's ...
Pretty paint doesn't cover up retarded a$$ planning.
Slapping a side mount license plate on a 250K bike just screams we spend 1/4 mill and forgot it needs a license plate to ride on the street ... then when the dmv gave us the plate, we went omg omg omg where do we put it where do we put it, and slap it on the nearest bolt near the rear end and go ... whew, dodged a bullet.
Like some genius thinking genius in the ancient world said -
5% of people in the world think.
10% of the people in the world like to think they think.
The other 90% would rather die than think.
Cool.
Srinath.
UPDATE.
New piston rings, new valve seals. Had a pinhole issue in the top of my tank which sealed up beautifully with Casewell Tank Sealer. Got it all timed ,torqued and back together aaaaaaaand. Same issue. Went through the carbs again and found the issue. An incorrectly set Dynojet needle. It was set way too far down and had a washer underneath explaining my insanely rich mixture. Put it on the second notch down and now it runs and idles with no hangs or surges or anything!
I am overjoyed that I got it all back together and running, what an experience. You guys and youtube allowed me to go from zero mech experience to a whole top end job.
Now my last issue is this power loss I am getting at 4 to 5k. I did a search and I have seen this a lot. It sounds like it is bogging (engine note gets flat and lower and loses power.) I think a big issue is the fact that there is a dynojet needle being used with a 122.5 main jet. Doesnt the dynojet needle need to be used in conjunction with a different main jet? Im thinking about moving it up to the first notch to see if I can get it closer or just order OEM needles and be done with it.
get oem needles. I chased my tail with those dj needles for a long time and problems completely went away with original needles. Now, I don't think this will fix your problem, but at least you will be able to diagnose it without the mystery of needle profile.
Quote from: mr72 on September 09, 2020, 05:31:57 AM
get oem needles. I chased my tail with those dj needles for a long time and problems completely went away with original needles. Now, I don't think this will fix your problem, but at least you will be able to diagnose it without the mystery of needle profile.
Sounds like a plan. It also looks like the guy before drilled out the left side whole on both of the slides, do those need to be replaced too? :cry:
I guess you can fill in the holes with JB weld and re-drill the correct size, or get some used slides. IDK where you are located but you are welcome to the spare set in my spare/parts carbs I have in my garage. I'll even ship them to you if you like, but it may take some time before I can get to it because I can't drive until mid October.
Hey thats really nice. I'll start with the new needles and see where that leaves me. The problem doesn't make it un-rideable just a little weak which is probably fine for getting back into riding after a few years.
Btw I dont think I ever said how much I paid for it. I got it for 575. I think I put about 5 to 6 hundred into it but the knowledge/experience/confidence I gained has been priceless! Like an engine repair class where you get to keep the bike haha.
Those bigger holes could very well be causing precisely the problem you are experiencing. Just saying. It screws up the vacuum balance between the top and bottom of the diaphragm.
Someone armed only with the internet modified those carbs at some point.
Quote from: mr72 on September 09, 2020, 07:24:48 AM
Those bigger holes could very well be causing precisely the problem you are experiencing. Just saying. It screws up the vacuum balance between the top and bottom of the diaphragm.
Someone armed only with the internet modified those carbs at some point.
Yes you are probably right. Everything else on it seems fine. I am located in Germantown Maryland. That any close to you? I just looked up the price of those slides. I would definitely be interested in working something out for your spares!
I'm right by Austin TX but I'm on crutches until mid-October so I can't get out to ship anything. But you are welcome to them once I can drive again. Probably cost like $10-12 to ship.
OP, if you need something sooner, I sent a link to a set of slides, diaphragms and needles. I had it on my watchlist from earlier in my project
Quote from: Sporty on September 09, 2020, 11:37:27 AM
OP, if you need something sooner, I sent a link to a set of slides, diaphragms and needles. I had it on my watchlist from earlier in my project
Thanks for the heads up! I might give these a shot at that price.
Quote from: aconti2 on September 09, 2020, 12:52:53 PM
Quote from: Sporty on September 09, 2020, 11:37:27 AM
OP, if you need something sooner, I sent a link to a set of slides, diaphragms and needles. I had it on my watchlist from earlier in my project
Thanks for the heads up! I might give these a shot at that price.
If you are chasing more jets and o-rings etc... I used these kits in my rebuild. Made in Taiwan. Everything seemed good quality and all the o-rings fit.
It has a lot of parts. It's based around the 37.5/122.5 calibration. I compared the needles to my stock one, measured in several spots it seemed the same.
I used different jets because of the mods the bike has (lunchbox and slip-on)
The only o-ring it didn't have has was the o-ring for the plastic end of the float carrier.
I sourced that from the local hardware store.
https://www.ebay.com/itm/2X-Carburetor-carb-Repair-Rebuild-Kit-1989-2000-GS500-GS-500-GS500E-US/323338869308?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160727114228%26meid%3D938fa79d464a4b13a700d7538f4ebfc3%26pid%3D100290%26rk%3D2%26rkt%3D4%26mehot%3Dag%26sd%3D353191053907%26itm%3D323338869308%26pmt%3D1%26noa%3D1%26pg%3D2060778%26brand%3DDamineding&_trksid=p2060778.c100290.m3507 (https://www.ebay.com/itm/2X-Carburetor-carb-Repair-Rebuild-Kit-1989-2000-GS500-GS-500-GS500E-US/323338869308?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160727114228%26meid%3D938fa79d464a4b13a700d7538f4ebfc3%26pid%3D100290%26rk%3D2%26rkt%3D4%26mehot%3Dag%26sd%3D353191053907%26itm%3D323338869308%26pmt%3D1%26noa%3D1%26pg%3D2060778%26brand%3DDamineding&_trksid=p2060778.c100290.m3507)
(https://iili.io/23eZOX.md.jpg) (https://freeimage.host/i/23eZOX)
Ok so I pulled the plugs today to check the spark and found that one plug was a pinch lean and the other was crazy rich. Hmmm something not right at all. I'll admit I took the lazy route when adjusting the needles, doing it without taking the airbox out (hate that thing.)
Anyways one diaphram wasn't seated well and was going up way too fast (the rich plug.) The other was all jacked up and wasn't opening (the lean plug.) So that explains why it could do some low revs but was falling on its face anywhere else. One carb was pouring in gas while the other was giving it nothing, oh boy.
Fixed up the slides and holy shaZam! this thing can GO. I know I haven't ridden in a while but how do people call these slow? I could barely open it up on my local roads. Can't wait to take it for a longer ride! I'll probably keep fiddling with it once I get those other parts is but this thing is really almost there! Thanks so much for your help everyone! I'll take a sweet picture tomorrow to share my new beaut.
Quote from: aconti2 on September 11, 2020, 05:21:42 PM
Fixed up the slides and holy shaZam! this thing can GO. I know I haven't ridden in a while but how do people call these slow?
good job getting it sorted. Glad you fixed it up! :thumb:
as for calling them slow, I think three reasons.
1. The internet says they're slow and people just repeat what they heard in fear of appearing stupid
2. They associate "fast" with that feeling of lots of torque at a low rpm, maybe they never revved it up beyond like 5k
3. They are used to riding something with a lot more power like a gsxr
Reality is that a properly tuned GS500 will do 0-60 in under 5 seconds which is pretty freaking quick. My Bonneville has 30+ more hp and is barely quicker, although it feels a whole lot faster because it has a ton more low end torque. But a sv650 or air cooled Monster or mt07 all have 65ish hp are gs500 weight and are much quicker. So that's probably the 650 class middleweight standard for quickness.
If you keep it over 6k my GS is plenty quick. With a 14T sprocket it's hard not to keep it above 6k. But with stock gearing you have to work and plan ahead to keep it in the power band. Get the gear changes wrong and it's easy to come out of corners sitting at 3k rpm and barely get to 6k before the next corner, it'll feel pretty slow. A 650-800cc twin redlines 3k lower so that same 3k-6k maneuver is in the meat of their power band and it feels a whole lot faster.
Fwiw I personally don't care about going fast, I just changed my sprocket so the GS would be different from the Bonneville and give me some variety.
I'm right there with you. Riding a motorcycle for me is about being in the open air and the joy of leaning through turns. I can't see myself needing something faster for a long while. I have a lot to learn. My first riding experience was cut short by someone pushing all the motorycles over at my college parking lot and an SV handlebar going through my ninja 250's radiator.
Am I real Gs Twinner now? Not too shabby for 575.
(https://i.ibb.co/X4VY1ys/IMG-20200912-125500-495.jpg) (https://ibb.co/LPvNmQt)
Ok I got the OEM needles in. It seems to have smoothed it out a bit. Only issue is now my throttle/clutch play is a little off when taking off from a stop. The DJ needles required a softer touch with the throttle when taking off (due to the aggressive taper i assume) so now I have to give it a bit more throttle for it to take off smoothly. The good news is when I get it right I feel like I have a lot more control. Just gotta practice now!
Any tips on adjusting the mixture screws while on the bike? My screws don't have a very deep slot so its really hard to tell if I'm doing anything. Its pretty tight in there. I'm about to just take them off completely and adjust them but that will take forever.
I'm using a bit that connects to my wrench.
I have a little stubby flathead screwdriver especially for this that came from harbor freight. I've also just used a normal flat screwdriver bit like you'd use with a drill.
I have one of those. My issue is the screw doesn't have a deep enough slot and it the screws don't turn super easily which makes it a very tough combo to adjust upside down in a tight space. I might try one of those screw extenders when I service the valves this winter.
Or not, it runs pretty well. I'm really only having a slight issue at take off from a dead stop. It's just a little noisy.
That's a great shot aconti! :thumb: I use bits myself,...have a couple I especially like. Dabbed some paint on the side so I can count etc etc,...