Hey all,
1997, stock exhaust, air filter. 125 main, 40 pilot, 3 turns out.
I've had a flat spot from 3-5k for the past month or so, which generally goes away once the bike is fully warm, but for the 15mins it takes to get there, its pretty boggy..
Went out today and notice some popping in the exhaust, mostly at low rpms and when down shifting.
Did some work on the search function, but not finding a lot with the two issues combined... Could this be a running rich issue? Perhaps fix with a simple additional turn on the mixture screw?
Valves were checked a couple weeks ago and the only one out of spec was the right intake. It was somewhere between .076 and .102 at a 2.65 shim, so I swapped to a 2.7. Maybe my thinking was wrong here? However since I've done that, it's eliminated what I'll call a 'hiccup' during warm up.
Any help appreciated!!
What you describe is a lean condition. Are your exhaust bolts tight? Good exhaust gaskets?
When was the last time you cleaned the carbs? Mixture screw is only idle. You need to put washers under the needle to increase midrange mixture. I'd bet it's a combination of dirty carbs or exhaust leaks.
Get Brisk plugs....(just kidding!)
Cookie
Quote from: lboaman on September 14, 2012, 10:14:30 AM
Hey all,
1997, stock exhaust, air filter. 125 main, 40 pilot, 3 turns out.
I've had a flat spot from 3-5k for the past month or so, which generally goes away once the bike is fully warm, but for the 15mins it takes to get there, its pretty boggy..
Went out today and notice some popping in the exhaust, mostly at low rpms and when down shifting.
Did some work on the search function, but not finding a lot with the two issues combined... Could this be a running rich issue? Perhaps fix with a simple additional turn on the mixture screw?
Valves were checked a couple weeks ago and the only one out of spec was the right intake. It was somewhere between .076 and .102 at a 2.65 shim, so I swapped to a 2.7. Maybe my thinking was wrong here? However since I've done that, it's eliminated what I'll call a 'hiccup' during warm up.
Any help appreciated!!
Quote from: twocool on September 14, 2012, 10:33:21 AM
Get Brisk plugs....(just kidding!)
Cookie
Haha, oh you laugh, but I have some. They aren't the cause, or the solution to the issue (I've swapped with some NGK's today to make sure).
Another reason Im going to be using a wideband to tune my bikes carbs. I dont like guessing where the mixtures screws need to be
Here I go starting another "discussion" on something I found.
I have been thinking of getting extended mixture screws to easily play with the mixture:
Yes - you would have to get the right ones. These are sample pictures.)
(http://i1206.photobucket.com/albums/bb442/adidasguy/Technical/22550060-M.jpg)
(http://i1206.photobucket.com/albums/bb442/adidasguy/Technical/yhst-85354533410737_2227_17649343.gif)
I was looking at those last week and if you find some less than 20-30 EACH, you let me know
I called Factory Pro and ordered 3 sets. $34 a pair/set.
Long Boy Fuel Screw Set
Having a hard time adjusting your fuel screws?
Don't have a multi-bent twisty windy screwdriver to find that "all important for cruise" Fuel Screw adjustment?
Factory Pro's 4 pc. "Long Boy" Fuel Screw Set allows the owner to reach in and quickly adjust your fuel screws for best cruise and idle quality.
Contact Factory Pro
M-F, 9am - 6pm, Pacific time, -7 or -8 GMT
800 869-0497
USA and Canada
415 491-5920
fax 415 492-8803
parts information
info@factorypro.com
EC997 dynamometer information
info@factorypro.com
Product Support /Tech SECTION
click here
Quote from: adidasguy on September 14, 2012, 03:54:17 PM
I called Factory Pro and ordered 3 sets. $34 a pair/set.
Long Boy Fuel Screw Set
Have you done any tests to support these? :flipoff:
Quote from: codajastal on September 14, 2012, 03:59:16 PM
Have you done any tests to support these? :flipoff:
A little "testy" today? I'm sure I can screw them with my finger. Bend over so I can practice while I wait to get them.
Quote from: adidasguy on September 14, 2012, 04:11:12 PM
Quote from: codajastal on September 14, 2012, 03:59:16 PM
Have you done any tests to support these? :flipoff:
A little "testy" today? I'm sure I can screw them with my finger. Bend over so I can practice while I wait to get them.
Send me a plane ticket and I'll be right over! :thumb:
Quote from: adidasguy on September 14, 2012, 03:54:17 PM
I called Factory Pro and ordered 3 sets. $34 a pair/set.
Long Boy Fuel Screw Set
Having a hard time adjusting your fuel screws?
Don't have a multi-bent twisty windy screwdriver to find that "all important for cruise" Fuel Screw adjustment?
Factory Pro's 4 pc. "Long Boy" Fuel Screw Set allows the owner to reach in and quickly adjust your fuel screws for best cruise and idle quality.
Contact Factory Pro
M-F, 9am - 6pm, Pacific time, -7 or -8 GMT
800 869-0497
USA and Canada
415 491-5920
fax 415 492-8803
parts information
info@factorypro.com
EC997 dynamometer information
info@factorypro.com
Product Support /Tech SECTION
click here
http://factorypro.com/Prod_Pages/prods77.html
How do you know those will fit?
Weed, I checked and they were listed as an option under "GS500 Suzuki". If Adidas has more information as to proper fitment, I'll defer to him since i believe he ordered via telephone call. You are right though. There are many different carbs with many different sizes.
I will say that here in SW Ohio, I adjust these mixture screws a few times a year as it realtes to temperature. Colder temps like richer mixture. I do mostly commuting on the bike, so I like fast warmups.
I just adjusted my mixture screws now. It consited of my front facing camera on my iPhone 4s, and a little screwdriver bit "guessing" at a quater turn cause I am close, but no cigar quite yet. Been a tad rich in the pilot circuit so say my plugs. It's also 11:22pm and hard to see. The lighting in the garage is zero, so it's headlamps for me.
I'm interested in these mixture thumbscrews.
EDIT: Here are the direct links to the GS500s:
E: http://www.factorypro.com/Prod_Pages/prods11.html
F: http://www.factorypro.com/Prod_Pages/prods10.html
Scroll down a little, and you'll see it. Same part number for both E and F "CRZ-SCR-4030-M"
To the OP, we just did a serious thread jack. :oops:
You have a lean condition. Let us know how it goes. Any updates or questions, please let us know.
Yeah, at $45 a set ($35 + 10 to ship).......IDK. Just seems a lot for two screws :cookoo:
Quote from: jestercinti on September 14, 2012, 08:33:16 PM
To the OP, we just did a serious thread jack. :oops:
You have a lean condition. Let us know how it goes. Any updates or questions, please let us know.
Haha, thanks but I don't mind. I've seen those thumb screws for the mixture screw before; seems like a 'nice to have'. Might consider them if I have to keep tweaking.
I checked each bolt on the exhaust, but didn't find any loose. I ended up taking the mixture screws 1 more full turn out each (so at 4 turns out now). Popping gone, but there's still a flat spot from 4-5k while warming up. The spot is much better with the choke on a bit, and once warm, its more of a hesitation than a flat spot. Perhaps I have another air leak somewhere, but I can live with the way it is for now.
No...with 4 turns, you should probably go +1 on the pilot, and reset the screws to 2.5-3 turns out. At 4 turns, you are running the risk of them falling out.
Put a washer or 2 under the needle. That will help with mid-range.
I agree with putting a washer or 2 under the needle. I wouldn't change your mains or pilots. 125/40 seems to be the sweet spot for this bike with the stock air filter.
Jetting is a black art. What works best for one may not work best for another.
Try washers under the needle first. Then mess with the mixture screws again. That may solve your issue. Come to think of it, I have not heard of anyone putting in larger than a 40 in the pilot.
I think the reason I like 125/40 is because it's the stock sizes in the UK where they didn't have the same emissions restrictions. I would assume that it is the best for the bike since it came stock that way. Of course weather and altitude can affect jetting, so there might be differences due to that. If your jetting needs deviate too much from this without extreme weather or altitude, I would look toward other issues, such as air leaks, exhaust gaskets, valve clearances, and other engine issues.
As far as the jet needle washers, I don't know if they had the same jet needles in the UK or not, but the flat spot at 4-5k has been addressed by multiple people here on the forum by adding washers under the needle.
Thanks guys. I'm 99% certain I have one washer on the needle now, and I have a baggy full of em in the garage. I'll stick another on each, reset to 3 turns out and see where we are at.
They do use a different needle in the uk. It has a c-clip with adjusting notches like the dynojet ones.
I cannot speak to the taper of the needle, however.
I would love to know the stock number of that UK needle and needle jet so we could go to that set up, or determine how to approach it with washers. Anyone know?
I'm not sure if I've fixed anything. So I've replaced the exhaust gaskets, because I had checked the exhaust bolts and they were tight, so thought I would go the extra step. I didn't notice anything wrong with them, other than just being old and used. New and old below.
(http://imageshack.us/a/img651/4885/imag0523z.jpg) (http://imageshack.us/photo/my-images/651/imag0523z.jpg/)
I added another washer under each needle, and reset the mixture screw to 3 turns. Took it for a spin around the block and was getting similar behavior as before. The exhaust popping and flat spot (although it seems to be lower in RPM's now, around the 3k mark). I reset to 3.5 turns out, and got similar results. However, it is noticebly better with the choke on. I am linking a video below trying to show the difference when the choke is on (just a smidge) and off. Apologies for the cell phone video...
http://youtu.be/-hGhssbBKTE
Any thoughts? For the time being, I can ride around with a little bit of choke on and be careful during the flat spot (notice I'm hoping the two are related).
BREAK
On a "what stupid thing have you done today" note: when I took the bike around for a spin, I noticed the front end was squishy. Took it back and found it at 13 PSI. Dummy. Thought "well, might as well check the back tire, too". The tire pressure gauge wouldn't even get a reading! Couple pumps of the bike pump, and back up to 36. *face palm*
BUMP
Any ideas? Would a tight intake valve be causing my issues?
Thanks for the help!
Quote from: lboaman on October 03, 2012, 11:43:57 AM
BUMP
Any ideas? Would a tight intake valve be causing my issues?
Thanks for the help!
Comprehensive checklist:
1. Air Pressure in Tires (well..not really, but I thought I would have some fun :thumb:)
2. Air cleaner CLEAN
3. Valves in spec (most important)
4. Plugs in good condition and clean
5. No air leaks between carb and engine. This includes boots and o-rings
6. No exhaust leaks
7. Carburetor clean (meaning no dirt, varnish, etc).
8. Battery strong (weak battery = weak spark).
9. Might be fuel flow. Kinked hose? Tank valve set to "partial on"?
10. Turn fuel chicken to PRIME. Run OK then.
11. Ignition system.
Thanks Jester. Looks like I finally have gotten to the fix.
I went back and checked my valve clearances again. The right intake was tight, so I swapped it back with 265. Started it up, same problems.
I thought my carbs were pretty clean, but I gave it one last ditch effort. Sure enough after a good cleaning (well, good enough, just blew out every hole with carb cleaner), and I had a change. Now when i started her up, she jumped straight to 4k RPMs. Having played this game with high idle before, I was fairly certain I had an air leak somewhere.
Couldn't find anything with the WD40 tests... Thought I was spraying everywhere. As I was fiddling with the mixture screws, I noticed one of the hoses connecting to the emissions canister was coming loose (the ones that T up). The hoses were pretty old and brittle. Cut some new ones and started back up with no high idle. :thumb:
Been riding around for past few days and it's running pretty good I must say. I'm thinking that extra washer under the needle has made a bit of a change, because it seems like theres a little more 'umphhh' <- technical term.
thanks for the help!
Glad you got it fixed. I'll add vacuum leak to my checklist.