I installed a mikuni 44 sidedraft and had a very slight bounce in rpms at idle < 100rpm difference barely noticeable on the tach but audible, I just did a master rebuild for my carb I bought from Wolf Creek Racing and confirmed with them all my jetting is correct for a stock port 12a.

I purchased and installed new ngk plugs

New wires

checked spark on each wire... ok

I have a small booster vac leak so I disconected and capped the outlet on my intake to make sure that wasnt the problem (still bouncing)

Set timing from stock up to 24L 16T adjusting mixture along the way (still bouncing)

worked from 3.5 psi on my fpr to 5 psi and back and still bouncing!!!

checked bolts on intake to engine and carb to intake... all tight... bouncing...

I have 83K on my 12a and I baby her... her oil is changed whenever it starts changing color and shes never gotten hot....

I may be nit picky but what can cause this bounce besides what i have checked so far?

Was thinking about sea foaming when I get down to an 8th of a tank?

Any other ideas please let me know.

 

My mikuni does this also. I just took it as normal and lived with it. Plus it gives it a slight BP sound anyway Atl east with a RB Streetport system.

 

funny... thats what i have... an rb streetport system....

guess i'll just live with it also.... thanks

btw... i wish the search function used the same algorithm as the bottom of this post uses for similar threads... it seems to find more acurately.