I put a new slip on on my bike this past year. It runs fine when but when I'm stoppped at a stop light the RPMs jump up and down. Usually from 1200 to right around 1500-1700 than back down. Someone told me that I might need my carb rejetted if you put on a slip on. It's a 98 CBR 600. What'd you think?

 

Sounds kind of like a vac leak. If so you can find it with carb cleaner. The carb cleaner will mix with the air leaking in and cause the motor to rev up.

In Honda cars the fast idle valve can cause this also. I'm not sure if this is also true on the bikes.

 

mapping might be off now b/c of the slipon
might need carb synch

like CRF said put some carb cleaner

 

I had the same thing, I just got a manual cam chain tensioner and it made it much better, it still jumps like 50 rpms but it is a lot better then +/- 250 but it probably is partly carb synch as well

 

what if i wanted to find a vacuum leak on an FI bike... would FI cleaner work too

 

Yeah, it will work with any vac leak.

 

Is the carb synch a do it yourself type thing or taking it to the shop?

 

totally do yourself!