bad idle

[coreo19]

1994 fzr 100 exup. will start up fine and idle perfect but after you drive it for a couple miles the idle goes crazy. one time its idleing at 3k then it drops to 1k then jumps back up to 3k. 100% positive the carbs are clean. just put brand new carb boots on there. the boots helped out alot helped out alot but the idle is still going everywhere. ive let it set there and idle for a few minutes and the idle will just keep going up. it started at 3k and rose all the way to 5k and was still climbing before i shut it off. i do have about 1/8 inch of slack in the throttle cables. any idea's???

fyi. i put on a full yosh exhaust the same time as the carb boots. cleaned the carbs when changing the boots out. the idle problem was like this before i put the new boots on. i thought the reason of the erratic idle was bad boots because they were cracked pretty bad

[bikenut]

sounds likea vacuum leak could be the orings on the manifolds where they go to the heads or the boots or carbs

[haro504]

seems like something to do with the choke maybe the passage way is partially blocked and when it warms up it swells restricting the flow of air raising your idel

[sweekster]

I wouldn't say it's a vacuum leak as it wouldn't idle at all (in most cases anyway). I would say that it's probably out of synch carbs along with a mis-adjusted idle set screw. That's just a guess though.

[coreo19]

alright. i synched the carbs. they were a little off. all four carbs synched a little low below what the manual says. now i can take it up to 10k let off the throttle and it will come down fine. but it will stop at 1500 one time and i will rev it again and the idle will drop down to 300 and die??? air fuel mixture screw is 1/4 turn out. i am about 400ft above seal level, so i will go take it to about 1 3/4 to 2 turns out and see what happens

[sweekster]

i have my idle air mixture screws at 3 turns out and mine idles at roughly 1250

[apsolus]

now you have obviously sprayed any suspect areas down iwht carb cleaner to see if idle would change right? that would be the best way to determin if its a leak somewhere

[coreo19]

sweekster got it...carbs were out of synch and idle air mixture screws were out of whack. she is perfect now. thank you all for your help

[kilika2]

sweekster got it

That's a running trend. Glad you got your bike running again.

Chris.