Idles rises and lowers can't figure it out

[jeremiah]

Hello smart people I am having problems and I don't know what it is. It idles up then goes back down to where it should then rises back up. Could it be a VACUUM leak I am clueless, I cleaned the carbs and set the float heights and everything was looking good. ANY IDEAS I AM WILLING TO TRY ANYTHING!!!! THANKS

[IndyGunner]

check the idle mixture screws?..... gotta drill the caps over em and then seat them... then 2.5 turns out

[forsaken]

carbs need to be synced or you have a vac leak
if you had the carbs apart it could be either
get a can of carb cleaner and start spraying with the bike running and see if iffle increases dramatically.
common vac leak areas.....
carb boots on the head and airbox
vac caps
vac port o rings
airbox drain tube aka puke tube
im betting on needing a sync though

[starion88esir]

carbs need to be synced or you have a vac leak

airbox drain tube aka puke tube

Should this one be capped off?

[jeremiah]

I'm going to try and synch them because I cleaned the hell out of them and set the floats and got all my hoses hooked up right THANKS to ARSENIC and the diagram he sent me I really hope thats it. I also set the idle air screws out to 2.5 and thats good to not running rich or lean. Thanks bro's

[Newbie2it]

Should this one be capped off?

Yes

[kjcorduan]

I had idle issue, #4 spark plug was shot, replaced and it runs better. Just a thought, have you checked your plugs?

[jeremiah]

Yep I check my plugs very often only thing i havent done is synch the carbs and I dont have a tool to do it so I gotta come up with some cash and take it to the shop. ALSO when I hit the rear brakes my brake lights come on but when I hit the front no luck. I know there is a front brake switch or relay but where is it?????

[loudnlow7484]

What year and size is it?

For the front brake switch.... follow the only two wires going to your brake lever. The switch gets crudded up sometimes. You might be able to just clean it out pretty thoroughly and make it work again. If it's outright broke, just get another one.

And for your idle issues........ welcome to the wonderful world of carbs! Definitely either invest in a synch tool, or make one. It can make a big difference if it's off. If you are ABSOLUTELY sure that the carbs are 100% clean, then I won't tell you to take them off again just yet....... but it wouldn't hurt..... you could use the opportunity to replace the bowl screws with hex headed ones (or socket headed, however you prefer to call them).
Another thing I would check, is to look closely (probably with a flashlight) at all your carb boots, top and bottom, with them installed. Sometimes when you push the carbs in, a boot can bend, and sit funny on the carb, giving you a big vacuum leak. All this is just a shot in the dark though. Figuring out carb problems is often just done by checking, and rechecking everything until you find the problem. Looking for vacuum leaks is a good start. The little o-rings for the vac ports are easy to lose, and can cause some running issues. Hope all goes well.

[jeremiah]

Thanks for the good info I will check all that you listed, and thats a good idea to replace those soft easily stripped float bowl screws. I will look around on a couple more threads to see how to make a synch tool because that would save at the least $50 bucks.
I just came in for a ride and the thing idles around 2500 to 3000 RPM's and occasionally jumps to 4000 so I would turn the idle screw down to about 1000 RPM's and then it will just konk out when stop giving it gas. Then I will idle it up just half a hair and it will jump back to 3500 RPM's. Theres no fine line when I get it where I like it to idle it don't want it, it wants to be at 3500 and thats too high!!! When I let off the clutch it snatches the drawls clean off me!! Any ideas??? ohhh yeah its a 93 kat 600

[DumbLuck]

clean, re-clean, and re-re-clean the idle circut an pilot circut. then do the carb sync. and keep lookin for peskey vac leaks. a hose can look perfectly good and yet have a crack or crappy end that's leakin. the sync port caps are notorious for this too.

[jeremiah]

Man I sure hate to take those darn carbs back off!!! I have been riding all day and I really need to fix that problem sometimes it idles perfect then it will rise to 2500 RPM's, its not going to 4000 RPM's no more. But it seems like the more I rode the better it got. I'm not complaining because this is my first bike and the best $200.00 I ever spent and loving it!!!! Guess i'm going to pull them back off and clean house AGAIN!Thanks again I appreciate all the info you all give me!!!!

[kevin2502000]

I always use compressed air after cleaning to dry and blow out any crap. If you have access to air compressor do that too. Don't feel bad about carbs, they are very sensitive to any dirt and I have had clean my again after I thought they were clean. Give them a long soak.