Hi guys,

Been frequenting these forums for years now. I am not very mechanically inclined, but I will do my best to explain this issue to you.

Background: Bought a used 2004 GS500F 6 years ago, ran without any notable issues up until the day I decided to sell it because I am moving. Did not start whatsoever, engine tried to turn on startup switch press and immediate loud CLANG and no turn over. Difficult to roll bike with clutch disengaged when it was in gear.

Had shop pick it up and open it up -- some part in/around exhaust valve came loose and fell into cylinder and lodged itself in there. Bought a used cylinder head and had shop replace it with piston and some seals. Bike STARTED without issue after that and all seemed good.

Went to shop to pick the bike up, had a difficult time trying to get it to idle without stalling. Figured it was because of cold Wisconsin weather, kept choke partially on and rode home. Turned choke off after a few minutes. Throttle felt responsive when turned. However, when coming to a stop, bike would stall almost instantly. I would come to a stop from 55 mph, downshifting along the way, and if i did not downshift and engage the drive quickly enough, the rpm would drop and it would stall.

However, this was not always the case. Along the same ride, I would occasionally pull in the clutch and my bike would stay at 3-4k rpm. Giving it some throttle, play with the clutch, shut it off and start it back up, the idle stayed at 3-4k until I came to the next stop and then it was anyone's guess as to whether it would idle high or die out again.

When it would stall even when warm, I tried adjusting idle switch to as high as it would go. It would still stall. However, when it was adjusted that high, giving it a little bit of throttle soared the RPM to 5-7k or so.

Took bike back to shop -- had them check for vacuum hose leaks and clean carburetors. I am a college student; no tools or space to work on things. Carbs cleaned, hoses no leak, rode bike back home again and the exact same issues present.

Brought back to shop yet again; they called Suzuki support and the agent said that some of the stock jets were too small and shipped some new ones over. Bike still at shop with new jets installed and shop tech says the problem still present.

Sounds like he is running out of ideas. Do you have any I can pass along?

Whaaaa that's a lot of near random things ... so -

Ok you have both symptoms of being rich and lean ... how is that possible - yes its possible if you have a sticking float and a clogged pilot jet, that will be lean @ all times except when the float is overflowing ... and please dont tell me they cleaned it ... the first bloody thing you do in any situation is diagnose the problem and have a theory for what could be happening. Even if it is cleaning ... how long did it sit with the dead motor in it ?

They want to change jets cos they are too small, and they ordered some from suzuki ... really, so suzuki sells bigger jets, OK I'll bite, I'd like a part number ? This whole thing sounds like a scam to me, or you're not explaining it right.

I dont trust shops period. But Really the ones that change parts first think about what may be happening later really are scam artists.

Ship me the carbs, I'll tell you what is going on or not going on.

BTW you broke an exhaust valve, that is enough to get that carb drowned in a hail storm of metal ...
Open and clean everything is a must there. I dont think it has to be super clean to work, a nice smattering of carbon is on all fuel system parts on nearly all vehicles. But you dont want metal dust in there.
Then -
How is the air filter ?
Did they wd40 test for air leaks ?

Cool.
Buddha.

Have them do a compression test while you watch -- this can be done without removing anything from the bike so it takes like 2 seconds on the GS (just have to pull the spark plugs--which are right there in plain view).  If it doesn't have decent compression (like over 150psi maybe?) in both cylinders, then they did a lousy job of installing your new piston and/or rebuilding the used head. 

Like Buddha says, the carburetors should be carefully cleaned, too, so we can rule out fueling as a source of the problem. But no good idle and needing lots of revs says low compression in one cylinder, to me.

Quote from: 5thAve on May 05, 2011, 01:22:03 PM
Have them do a compression test while you watch -- this can be done without removing anything from the bike so it takes like 2 seconds on the GS (just have to pull the spark plugs--which are right there in plain view).  If it doesn't have decent compression (like over 150psi maybe?) in both cylinders, then they did a lousy job of installing your new piston and/or rebuilding the used head. 

Like Buddha says, the carburetors should be carefully cleaned, too, so we can rule out fueling as a source of the problem. But no good idle and needing lots of revs says low compression in one cylinder, to me.

Hehe ... he's got an 04 ... takes freaking 45 mins to check if you got an engine under there or a lump of coal ...
BTW I'd leave the plastics out till the bike's running like a top. But then again I'd leave the plastics off period. The bloody carbs are easier to remove than getting to the spark plugs.
Cool.
Buddha.