the washers on the carb needles is a great mod. i put 2 #3 washers on them this weekend and the throttle response is better from 3000 rpm to 7000 so it gets to the sweet spot faster. i also have a 14t sprocket on it so that helps. if anyone is thinking of doing this mod do it its simple and takes under an hour
Yea ... but please post more details, like what year etc etc (I know yours is 01+ ... but those that dont know ...)
Yea #3's the shnitz ... but 89-00 #4 needed ... :icon_mrgreen:
Cool.
Buddha.
oh yeah sorry about that. its a 05 all stock except for the sprocket which i put on a month ago.
Did the plugs look any darker from your mod?
Yeah I put them on my 06. It helped a lot. My K&N drop in and 15 tooth sprocket came in today. I look forward to trying those out.
You 2 kids have the right idea. 1 small mod at a time and I guess you're keeping proper notes ??? no ... well, gstwin is a online note pad, I know what you did, and so do you.
Cool.
Buddha.
Ill bite. What exactly is a #3 washer? Is there an sae or metric size which equals a "#3"?
"Ill bite. What exactly is a #3 washer? Is there an sae or metric size which equals a "#3"?"
just go to any hardware store and ask for #3 washers they will know what your talking about, they are very small stainless washers.
"Did the plugs look any darker from your mod?"
i have not checked the plugs yet, i will in a week or two.
"Yeah I put them on my 06. It helped a lot. My K&N drop in and 15 tooth sprocket came in today. I look forward to trying those out."
let us know how the k&n works. will you be removing the restrictor?
I'm curious about why the 3 jet carbs need #3 washers and the 2 jet carbs need #4 washers.
I have a '94 and the Buddha sent me 40 pilots, 125 and 127.5 mains and washers, (not sure on the size).
I put in the 40/125 with one washer until I got my K&N drop in, then I added switched the 125's for the 127.5's. I went to the local hardware store for #4 washers, (I wanted to add 1 more).
I checked two different hardware stores and they both had #4 washers in brass only, and they were smaller than the ones the Buddha sent to me, (Buddha's were stainless). So I put in two of the brass #4's.
I am still having problems, bike is not running right.
I have a '94 with stock pipe, K&N drop in (no restrictor), 127.5 mains, 140 pilots, 2 #4 brass washers under each needle. I have disassembled the carbs completely and cleaned them thoroughly, replaced all Orings. Idle screws are 3 turns out.
The bike starts easily and runs well at all throttle positions and rpm's up to ~40 mph. Starting at ~50 mph up to about ~70mph it surges (bucks and jerks is a better description)
This happens only if I try to hold a steady speed, if I am accelerating it runs fine. If I run 75 mph or faster there is also no problem.
I am going to try adding another washer under each needle, as it seems to me that it is lean at part throttle. I am thinking that it is only slightly lean since it is fine at low speeds but at higher speed where I'm using more fuel this problems occurs.
I have not sync'd my carbs yet as I have a broken nipple on one of my carb tops, but visually the throttle blades appear to be close to the same.
I've been pulling the plugs about every 50 miles and they always appear a little lean.
Has anyone else had a problem like this?
sorry cant help on that one maybe buddha can
QuoteThe bike starts easily and runs well at all throttle positions and rpm's up to ~40 mph. Starting at ~50 mph up to about ~70mph it surges (bucks and jerks is a better description)
This happens only if I try to hold a steady speed, if I am accelerating it runs fine. If I run 75 mph or faster there is also no problem.
I'm pretty sure this is due to a lean condition. At higher speeds, the throttle is open more at a given rpm than at lower speeds (correct me if I'm wrong), so I'd say it may be your main that needs to be upped a size. If it were at lower speeds doing this, then you may have needed to raise the needle slightly more.
Hopefully this helps. Can anyone else confirm this?
Quote from: The Buddha on September 15, 2008, 09:33:46 AM
Yea ... but please post more details, like what year etc etc (I know yours is 01+ ... but those that dont know ...)
Yea #3's the shnitz ... but 89-00 #4 needed ... :icon_mrgreen:
Cool.
Buddha.
I have a 2000. What would you recommend for it? 40's and 125's? One #4 for each needle? I know that's not really the ultimate in performance for the GS, but all I'm really looking for is smooth throttle response and fewer idle issues. I'll keep SOME of my economy. Thoughts and recommendations?
quicktaco, thanks for the input. I'm pretty sure it is a lean condition.
Throttle response is excellent, smooth at any throttle position, can cruise steady at any speed up to ~40. Say, for instance, 1/2 throttle in 3rd gear is 40mph, I shift up to 5th, I have to reduce throttle slightly to maintain 40 mph, shift to 6th, reduce throttle a little more to maintain 40 mph. Now I speed up to 65 mph, I increase throttle up to around 1/2 throttle and try to maintain 65 mph, bike begins to buck and jerk. I open throttle to around 3/4, bike accelerates up to ~75 mph, I reduce throttle slightly to maintain 75 mph and have no bucking or jerking.
So my line of thinking is at the higher speed, same throttle position, the load is higher due to wind resistance, so I need more fuel. Seems as if there is not enough fuel at part throttle, but at nearly full throttle I have enough fuel.
I don't know if a larger main jet will give me more part throttle fuel or if that is a function only of the needles.
I added a third washer under each needle and went for a test ride. Symptoms were reduced somewhat but still there. I pulled over and put the K&N filter restrictor on. Part throttle cruise was almost perfect. I haven't pulled the plugs to check them yet.
I don't want the air filter restrictor to be part of the final solution, so I have two choices, as I see it: add another washer for a total of 4 (seems to be getting excessive) or go up a size on the mains (as you suggest).
In the jetting wiki and from other posts, my intake and exhaust combo should take the 127.5 main, so i have resisted going up another size. I think I'm going to do it anyway as I seem to be running out of options.
Oh, and it started harder this morning (I did the testing last night). Usually I choke it and it goes to 4k in about 10 seconds. This morning it didn't start right away on full choke, I gave it half choke and blipped the throttle a few times, it idled up to about 4k after about 30 seconds.
A larger main will give you more fuel at part throttle, say above 1/2 throttle or so, but it doesn't have as much of a change as the height of the needle.
You may have it perfect with one size large main, and 2 washers on the needle. I have the lunchbox filter, so I don't know first hand, but I think the K&N drop in is still a pretty high flowing filter...especially compared to the stock drop in. Also, if you are at or near sea level, then the air pressure is higher which would cause the need for a little more fuel.
I'd try one size larger on the main if you just want to test it that way. If you want to do a plug chop at full throttle, then that would tell you for sure. If you don't know how, do a search, cause there's a lot of posts about it.
Remember that the matrix is only personal experience. It's not going to be 100% right every time. And some peoples' thoughts of right on, might be broader than other's, so some information on there may be slightly off. It's always a trial and error thing when rejetting. I'm still working on mine to get it perfect (partly because I keep making new exhausts for it)
Hard starting can be attributed to a lot of things. It could have just been a damp morning, and the moisture in the air caused it. It also could be that your plugs are sooty and need a few turns of the starter to heat up enough to get and adequate spark. Also could be that your float level is really low. I'd say that if it doesn't happen often after this, then it was probably just a damp morning. If it's continually happening, then your plugs might be to blame. If anyone know of some other reasons, please add.
I am going to go ahead and try a 4th washer on each needle, and take the filter restrictor out, for testing purposes. I'll order a set of 130 mains as well, then do more testing with those in and different washer configurations.
I am at ~700ft above sea level. I see your point about different people's idea of "right on" could be different. I still haven't synced my carbs yet, not sure how much of an issue that is. My valves are all in spec. I do have an ignition advancer by Bob.
I read your muffler building thread with great interest, I don't have a welder of my own and it's been a while since I did any welding. I would like to put duals on my bike at some point and utilize mufflers similar to the one's you've built.
The morning that it started hard was similar to the previous morning, it also started hard that afternoon when I was leaving work, and then this morning as well. I last looked at the plugs ~50 miles ago. They looked a little on the lean side at that time. They have ~250 miles total on them.
4 washers is a bit much, might make you very rich in the middle. I have 2 washers and have a lunchbox and exhaust. Good for testing though. 700 feet isn't too high, so I'd say that you're getting a descent amount of air in, which might be contributing to your problems.
What kind of plugs do you have? Champions? If you do, trash them and get NGK's, I had Champions for about 5 days until they started giving me all sorts of problems. Don't know for sure if it's the plugs that are causing the hard starting, but it's worth a shot to pull them and take a look after all this adjusting of the carbs.
I agree, 4 washers sounds like a lot. I'm wondering if I have something plugged causing the midrange lean condition. Since adding a washer helped, and then adding the restrictor helped even more, I'm sure I need more fuel in the midrange.
I'm hoping the 130 jets with a washer or two under the needles will fix the midrange leanness without making me too rich on the top end.
I forgot to mention that my floats are right on, as tested with the clear tubing method.
I am running splitfire plugs at the moment, I do have a set of the stock NGK's.
When you get the 130's, I'd start with those and 2 washers to see where you're at. 1 washer would be too drastic, since you're saying it's better with more and the 127.5's.
For sure, if adding the restrictor helped, then that means that you're getting too much air and not enough fuel. The bigger mains should help for sure.
Haven't heard anything about splitfires with these bikes, but I'm sure they're good. Just check them to see if they're sooty or not.
Holee cow ... I totally missed this ...
I'll read it and get back to you Pkhoff ... sorry ...
Cool.
Buddha.
OK you have a broken vacuum spigot. You have to close it before doing anything, that is letting in air making it lean.
If you fix that, then washers, no more than 3, start checking float level and more of the fundamentals.
Trying to cruise and you have issues, but open throttle and it behaves = lean. Its called lean surge. Maybe toss a sock in the filter with the cuff wrapped around the restrictor.
I am thinking we need to cut down your air flow a shade to compensate for the lack of outflow. The mismatch in airflow capacity can do this dual nature thing ... its rich in 1 spot and lean elsewhere ... and goes right back to rich when you get past that ... which is atleast 1 reason I hate stock pipe with WFO filters. My eliminator totally misbehaved like that till I put a pipe on ...
Cool.
Buddha.
Vacuum spigot is plugged with epoxy, sorry forgot to mention that. I use the clear tube method to check the float level. The fuel level is right at the float bowl gasket.
I now have 4 washers under the needle, filter restrictor is out. I have a little bit of richness right off idle (stumbles a bit). Midrange is much better, WOT is great.
I want to try one size larger mains and lower the needles back to two washers and see what that gets me.
I really don't want to spend the money on a pipe.
You could always make your own pipe like I did. Cost me about 10 dollars, and my labor. :icon_twisted:
Quote from: pkhoff on September 24, 2008, 11:15:44 AM
Vacuum spigot is plugged with epoxy, sorry forgot to mention that. I use the clear tube method to check the float level. The fuel level is right at the float bowl gasket.
I now have 4 washers under the needle, filter restrictor is out. I have a little bit of richness right off idle (stumbles a bit). Midrange is much better, WOT is great.
I want to try one size larger mains and lower the needles back to two washers and see what that gets me.
I really don't want to spend the money on a pipe.
OK maybe try the restrictor back in ... I have nothing against sending you 130 and 132.5 mains really, but I can maybe save you some money and see if you get a better result.
130 and 132 will over cook you top end, but then you remove 2 of the washers it can affect the WOT enough to cover the larger main. And yea you lean out the idle part by screwing in air screws, you can just tip the mid range into lean territory and you'd need another washer there ... :o ...
BTW #4 washers - you have 4 of them ... yeow. If you got #2 washers well, its not that bad. The thicker washers ... 4 of them is really uncharted waters. You have any air flow into the airbox other than filter. Like the hose on the bottom is there and intact ? what about the top one to the valev cover.
Also tell me does it behave better if you open throttle slowly, but misbehaves if you open throttle fast ...
Cool.
Buddha.
I tried it with and without restrictor in each configuration, I've tried to change only one thing at a time. Restrictor helps the midrange but seems to choke it on the top end.
When I added the 4th #4 brass washer I measured the thickness of them. They ranged from 0.0235" - 0.0255". Total thickness thickness of 4 came to 0.097". I measured the thickness of the stock plastic spacers that are under the needles, they were 0.105", so I've nearly doubles the needle height from stock.
The drain hose appears to be intact, with the bulb thing on the end. I haven't tried just plugging the nipple to see if that changes anything. breather hose from airbox to valve cover is present and tight.
How fast or slow you open the throttle makes no difference. It runs like a striped ass monkey, crank the throttle wide open and it almost jumps out from under me. I can cruise at ~40 mph in 3rd, 4th, or 5th, with no problem. As soon as I get on the highway and try to hold a steady 55, 60, or 65, it begins to buck and jerk like running out of fuel. If I open the throttle and accelerate to ~75 mph everything is fine, I cruise at that speed for 12 miles without a hiccup. 12 miles is distance on the highway I travel to/from work each day.
I tried this mod on my 2007 gs500f. Stock bike besides k&n drop in with restricting ring in place. Added two #3 washers to each needle. If i open the throttle quickly it with pause and go, pause and go. Far from smooth power. Does not backfire. It feels mostly ok if i accelerate slowly, but sometimes does the same. Also noticed the bike now de-accelerates slowly with the clutch in. Any advise on what to do? Add a washer or remove one? Forget it and go back to stock?
At least i have those horrid bolts out of the caps of the carbs and wont have to deal with that again.
Edit:
As i cant leave anything alone and plan on doing a bit of a trip on sunday, i went ahead and removed one of the washers. Would ride it but already had two beers with dinner and just popped open a third. I put it on the center stand and revved it quickly in first with no issue, but i guess that doesnt mean much when the engine isnt trying to push six hundred pounds. :cheers:
Quote from: respite on September 26, 2008, 06:56:40 PM
I tried this mod on my 2007 gs500f. Stock bike besides k&n drop in with restricting ring in place. Added two #3 washers to each needle. If i open the throttle quickly it with pause and go, pause and go. Far from smooth power. Does not backfire. It feels mostly ok if i accelerate slowly, but sometimes does the same. Also noticed the bike now de-accelerates slowly with the clutch in. Any advise on what to do? Add a washer or remove one? Forget it and go back to stock?
At least i have those horrid bolts out of the caps of the carbs and wont have to deal with that again.
When you put the washers in did you re-adjust your mixture screws? What about a vacuum test to sync the carbs? Do yourself a favor and follow the proper mix-screw-adjustment guidelines.
1. After any carb mod screw the mix screws all the way in and then back them out 1 turn a piece.
2. Start the bike and let it warm up, after it warms up drop the idle RPM to 900-1000. Turn off the choke.
3. Unscrew the mix screws until the motor doesn't rev any higher. Do this in 1/2 turn increments. DO BOTH CARBS AT THE SAME TIME!!! 1/2 turn on left, then 1/2 turn on right.
4. Drop the idle back to 1000 rpm.
5. Blip the throttle to 1/4 or about 3k rpm. If the needle hesitates on the way up you are too rich. If the needle drops back slow to idle, you're lean.
6. When you're done, both carbs need to be the same setting. Set the idle back to 12oo rpm.
My bike has 1 needle on each and I'm running at 3.5 turns out on the carbs... so you might be right around there.
Dan
Negative. I have a USA california model. Carbs are still sealed. Ive seen posts from other users on this board who threw in a few washers without removing the carbs and no mention of any other adjustments.
Well.. you need to. Plain and simple. You've got to take the carbs off and drill out the brass bushing. Takes about 3 minutes... then just pop them back on and throw the bike together...
Dan
Quote from: Danny500 on September 27, 2008, 05:15:51 PM
Well.. you need to. Plain and simple. You've got to take the carbs off and drill out the brass bushing. Takes about 3 minutes... then just pop them back on and throw the bike together...
Dan
I agree. You really should adjust them after changing anything else on the carbs. They'll be slightly off and can cause problems if left alone.
Bored at work I just took a minute away from the desk and took a look at my carbs. This bike has only been in the shop once for the 600 mile service. To my surprise, they drilled out the caps for the air mixture screws! Im going to put the second #3 washer back on the needle tonight and readjust the mixture.
Anyone know why a shop would bother doing this on a brand new stock machine? Im glad they did, one less thing for me to hassle with, but why?
It's possible that the mixture screws may have been slightly off from the factory. They could have done it to adjust it slightly to get it within spec again.
I just did this on my bike and talk about PROBLEMS! The bike is running sooooo rich, its blowing smoke, wont start, have to rev the crap out of it to get it to turn over.....
Then again, could be because there is not much fuel and the battery needs recharging......
Will have a look tomorrow arvo and post results here.
EDIT: I tried 1 washer on each, was much better but still starved for fuel. Put it back to stock and went for a ride, it backfires, jerks around, still starved for fuel. Not sure whats wrong with it, anyone know???