just bought a 99 600 f4 and it runs rough its hard to start some times and some times cranks right up and dies every time I try to give it any gas unless I roll back very slowly and work it up to a higher rpm not sure where no tac then seems pretty smooth. any ideas on where to start? Is it I need to clear my carbs or is it a syncing problem? thanks for any help new to carbs my last bike was fi

 

I would give your plugs a shot before you start blaming the carbs. When my carbs were dirty on my old Katana I was able to put seafoam through a vacuum hose and that cleaned it up pretty well. Though be careful because sea foam can foul plugs too. If you can get it running decent, run the seafoam through a line AND change your plugs and see if it works.

 

Sounds like fuel starvation at small throttle openings, which is usually a sign of blocked pilot jets. Another cause cold be that the idle mixture screws are incorrectly set. Screw each one in gently until they bottom out then back them out again about one and a half to two turns to start with and see if that helps the idle speed. If you manage to keep it running after that turn each mixture screw by the same amount in or out to achieve the smoothest tickover. A blocked or dirty air filter won't help either so check that as well. Plugs could do with a clean as suggested by another member so have a good look at them and check the gaps while you're at it.

 

thanks guys. well pulled my carbs today and cleaned them and got alittle better so I might try the plugs didnt really think that that would be it but you never know and got no air box on right now so dont think that has anything to do with it. and where are the idile mixture screws at? kinda silly but like i said never messed with carbs before. thanks for the help guys!!

 

Do you mean the air box hasn't been on while you have been having this problem? If so the answer is right there! Put the airbox and filter back on and see if things go back to normal. Having no airbox and filter will mess up the carburation no end! Hope I read your post correctly?

 

no no air box didnt have one on when i bought it but i have allready got on on ebay hope it gets here in a few days. hope that btween that and the plugs should do the trick if I havent got them to far out of sync messin with it!

 

When you pulled your carbs and cleaned them, can you provide any detail on what you did and how you cleaned them ? Did you take them apart to the point that there was nothing left to be taken off them, or you just removed the bowls from the carbs and cleaned the jets and outside ? There are some really teeny tiny holes that specifically deal with the throttle exactly where you're describing. If they're not clean, you're going to have problems. 3 little holes right by the base of the butterfly.