OK, after rejetting, everything seems fine, runs great, but if I blip the throttle I get a small backfire, sounds like it is coming from around the carbs.

20, 62.5, 137.5
UNI Drop in
Wileyco

What is causing this?

Anybody?

A little popping is typical when you open up the exhuast to be more free flowing.

Dgyver, hes backfiring through the intake.

Sounds like maybe a valve problem? Mine did that when i bent two valves.

Did it run ok before the rejet?

Ill wait for srinath to comment here.

Yep, ran fine before the rejet. It runs fine now too, now it doesn't do this everytime I blip it, only occasionally.

same here...It happens around 1400 rpm,when you close off the throttle.

i found it to happen when its not that warmed up.

Sounds like it might be loading up, a little rich at idle.  Thats my guess.

What if the slides are coming up to quickly. I know that on an HD if you get too lean of a shot on throttle application you will get a backfire through the carbs. Also does it on automotive engines. Seeing as how the little Baby does not have accelerator pumps I would think this could be plausible. I love my freshly washed Baby and this forum.

C.......