Hey guys having a slight issue that i cant seem to diagnose. Bike starts up and runs fine, but when im going down the road and then left off the throttle, and then give back onto the throttle, im noticing a puff of "white" smoke coming out of my exhaust. I'm not really sure if its blue smoke, but it definitely looks greyish-white (only really way i can get it to do it is going down the road and its kinda hard to see the color of the smoke). I want to say this is a sign of leaky valve seals because i didnt replace my old ones when i did my top end rebuild a couple months ago, but im getting conflicting opinions because my buddy says it could be my carb settings since there is black soot on my taillight/fender on the exhaust side possibly from it running too rich/lean. My coolant levels are fine so I don't think im leaking coolant. I just recently put a new high flow slip on exhaust, I didn't notice it before when i was running the stock exhaust but also during that period i was still breaking the engine in. I've got a 2009 klx250s, FMF powercore 4, dynojet stage 2 needle in 3rd clip with the 132 main jet, no airbox lid, my elevation is around 800 feet.

What could be causing a puff of white smoke on acceleration? It doesn't appear to do it when im taking off from a stand still, only when i let off the throttle at speed and then give back onto the throttle. Not billowing smoke either just a noticeable puff out of the exhaust. Any help much appreciated.

 

Are you checking the coolant level at the rad in the morning before starting the bike?

 

It was the valve seals. After further examining the smoke it was definetly blue. So i pulled the top end and replaced the valve seals. So far no more smoke, lets hope it stays that way