Hi,
Let me just start by saying i love my gs500, but it seems i've had nothing but trouble with mine. Here is what is going on with it.
Before i purchased this bike the previous owner put a high flow after market air cleaner on it. He also cut the baffle out of the stock pipe. Ok it was running lean and had all the symptoms of needing rejetted and the carburetors cleaned and balanced. So i took it to a dealship and had that done to it. Needless to say never go to yamaha of columbus if you're ever in ohio. When they returned the bike to me it had new fuel lines but they forgot to put the clamps back on (which made a lovely mess on my garage floor) they scraped up my tank etc. It also now had a hesitation from 2-3 rpm to where it wanted to stall. Also when holding the throttle at a crusing pace the bike felt like it was lurching backwards and "pulsing". I took it back to them and they claimed it to all be the baffle being taken out of the stock pipe. My father claims that you can tune any bike to any pipe and the baffle being taken out shouldn't make a difference.
Ok so i was riding the bike for a while in this condition, and stupid me i ran out of gas on the freeway. That was the most fun i've had in a while hah. It seems the dealership also had the fuel lines mixed up so i was actually running on reserve this entire time with no fuel to spare. so after pushing the bike to the nearest gas station i refueled put it on the prime position to get her started then put it back to on after she had ran a few minutes.
All seemed well until about a mile down the road it started sputtering again like it was out of fuel. So now the bike will only run for short amounts of time in the on position. To keep it running i have to keep it on prime. The engine is backfiring out of both carburetors one or the other at idle. It does this at the carburetors as well as makes a nice popping sounds as i decelerate. We though maybe i had a bad petcock which may be one of the issues, but it doesn't account for the engine running the way that it is. at running speeds it's still doing the pulsing mentioned earlier as well as a lack of power, it's like the bike wants to go but it can't get enough air/fuel to do so. Any additional information that is needed i can provide. I've only had this bike for 2 MONTHS! i just want her running correctly for once. Any ideas would be helpful.
Zach
Oh yea, any pipe and any filter I will jet it to near perfection. Just that with the common setup's stock pipe, or aftermarket slip on or full system, Stock filter, K&N in airbox. K&N lunch box etc ... I can jet it with a mail in and you prolly wont have to touch a thing.
So yes they screwed up, and if they cannot jet it with the baffle partially cut/drilled out, you take a sledge hammer and knock 1/2 their teeth out. Then call back in a week and ask them if they have indeed died of starvation.
BTW I will jet it in my sleep and ride it cross country with what you have told me. Cut baffle = slip on. That's all you need to know. There is enough variation and forgiveness in the bike to have it run like a charm no matter what.
Cool.
Buddha.
Your petcock is bad.That's why it has to be in the PRIme position.You are having fuel starvation issues because of this.See these links for a cure.
Eliminate the petcock vacuum operation.I do this mod.PM me for details.
http://gstwins.com/gsboard/index.php?topic=19363.0
Cheap alternative.
http://gstwins.com/gsboard/index.php?topic=36958.0
Also,any time the air filter or exhaust is modified the cabs must be rejetted and tuned.
Right, what my thoughts are is sure i have a clogged/bad pitcock but that isn't why the engine is running incorrectly. If i put it on the prime position the engine should have no issues running and currently it does. I "think" that the dealership but the carbs back to stock and did not tune them to the missing baffle my pipe so that could be the issue. Not sure, what do you think ?
Quote from: xakeriah on July 03, 2008, 11:00:46 AM
Right, what my thoughts are is sure i have a clogged/bad pitcock but that isn't why the engine is running incorrectly. If i put it on the prime position the engine should have no issues running and currently it does. I "think" that the dealership but the carbs back to stock and did not tune them to the missing baffle my pipe so that could be the issue. Not sure, what do you think ?
Part of it is the petcock.The internal orifice that supplies the PRIme is half the size of the hose fitting.It slows the flow enough to cause fuel starvation.