hi guys, my gs500 has a vance&hines super sport exhaust, an in the box k&n filter And a stage one dynojet kit and my bike has been giving me problems lately. THe bike ran fine for a long time with all the hop ups on it but it started to run crappy in the lower gears when i was riding through town at about 25 mph i would give it some gas and i could hear the pipe start to pop and studer, so i let it sit overnight and went out the next day and put the choke on like usual and started it and usually when i let the bike idle a little while when it's cold with the choke on the bike will run at a little higher rpm. well it didn't do that at all, so i immediatly shut the choke off and it seemed like the bike flooded out, so i rode it for a little while and it ran just as crappy as the day before. so i parked it in the garage and tore the carbs off the bike and found out that the problem was a worn out o-ring on this metal seat that held the float in place so i replaced the o-ring on the left carb the one that was giving me the problem and also the right carb. so i put the carbs back together and put them on the bike and put the rest of the bike together making sure that all the fuel hoses were in the right spot and everything else and double checked everything. after i got everthing put back together i rode the bike, and it ran great until it got warmed up, then the bike did the same thing as it did before. the exhaust would studer and pop at slower speeds and at cruizin speeds, but it wouldnt do it when you cracked the throttle and went through the gears, but as soon as i let off the throttle you could hear the exhaust pop, so i drove it home and tried addjusting the fuel mixture screw and that didnt do anything, i also checked the spark plugs and the left cylinder plug was much blacker than the right cylinder plug even after i tried leaning out the carbs, and both carbs were adjusted equally. i know the right cylinder is running just the way it should be. but the problem ive been having is either with the left cylinder or the left carburator. after every time i leaned it out i also checked the each spark plug and each time the left spark plug was much blacker and a few times i found that the gap on that spark plug was completely closed. i even had my dad sit down and try to figure it out, he spent an entire day with it and he knows motors like the back of his hand, and he even was stumped by it. my last resort is to take it to my suzuki dealer and have him look at it. if you guys could answer my problem i would greatly appreciate it. ;) :o
Do you get a blue spark on both plugs? did you try to replace them?
I would also try to clean the carbs thoroughly with carb cleaner if you haven't done that yet.
yes i checked both plugs for a blue spark and the carbs have just been cleaned recently
You might have something floating around in your cylinder if the spark plug gap is closed. That's usually a sign of something hitting it. I can't think of any other way it would go closed. Might have to pull the head off to check.
Sounds like you need to get the valves done. Did you balance the carbs after all this? Check the float levels?
Can't imagine how a spark plug gap can get closed unless there is something bad wrong.
The problem MAY be electrical.
Your symptoms aren't as definite as when my bike was running on one cylinder, but I still think you may have a flaky connection somewhere.
There are two threads that you may want to check:
1) Running on one cylinder.... (http://www.gstwins.com/forum/viewtopic.php?t=811)
2) no spark now (http://www.gstwins.com/forum/viewtopic.php?t=1696)
The first thread describes my symptoms and the solutions I tried early on. The clue to my problem was spelled out in the first post by jc, but I didn't figure that out until later.
The second thread describes what the problem turned out to be, and how to do some diagnostics to see if you have a similar problem.
And this never-before-posted picture shows the individual (pink) connectors that I used to replace the corroded black connector that turned out to be the culprit:
(http://www.bbburma.net/MiscFotos/100_0272_CorrodedConnectorBypassed.jpg)
See your Clymer manual for wire colors and resistance values, and feel free to PM/email me with questions if this info seems to be pertinent to your problem.
The strangest part of my ordeal was that whenever I tested for spark I got what I thought were nice blue "gap jumpers". After it was over I was surprised that I had been getting a spark at all. Maybe they were just mis-timed?
EDIT: Changed link(s) from sisna.com to bbburma.net