Blowing Blue Smoke

Hey guys I ran into a new issue with my bike.

I've been running my 08 490 big bore all of the last week but the other day blue smoke started spitting out of my exhaust... it ONLY does at when i let off the throttle.. not when i am on the throttle.

I'm running 91 octane premium fuel and there is no way that it could be mixed with oil in anyway before filling my bike up.

I just cleaned my air filter and re-oiled it a few days ago, is it possible that i over oiled it and filter oil can be getting in through my intake?

Is it safe to assume that i need to replace my piston rings? I do not know how many hours are on the piston itself but I did have it replaced just over a season ago maybe a season and a half.. I do not race my bike i ride it leisurely but I am hard on it i don't putt around when I ride. Is it safe to say that while i'm pulling my top end apart that i might as well and replace my piston and rings together? And if that's the case then I want to replace my timing chain while i'm in there so where is the cheapest place to go for a new timing chain?

The bike is parked until I can diagnose my issue and order parts.. frustrating to say the least but I hope I can get this fixed right away so I don't lose the beginning of summer for riding.. what do you guys think?

Are you talking about blipping the throttle on a relatively cold motor, in your driveway, or at the end of a ride?

Blue smoke means it's burning oil.

Your description sounds more like valve guides than piston/ring.

Those symptoms do not sound catastrophic, so I wouldn't park the bike...

Your simplest diagnosis is to do a leak-down test.

If you don't know how many total hours the motor has on it, make an educated guess, and follow the manual's best-case service intervals.

+ 1

either rings arent seated or valve seals are leaking oil from the head

No not when the bike was cold started. . When it was warmed up and ready to go. But my buddy who was riding with me when the problem started just told me that it was not blue smoke but white smoke

So is it possible that I simply just blew my head gasket and anti freeze is getting into my head?

I'm going to spray water around my head and see if I can find any leaks to confirm and I'm going to do a compression test one of these days so i'll let you guys know how those go

If you blew a head gasket, your exhaust would be sweet (if you use antifreeze) and your oil would be milky.

It won't leak out, it will leak in.

If your exhaust is white, that's usually excess fuel, from for example, a stuck ring or worn out rings....and blow-by.

Okay got it.. looks like i'll be ordering parts in the next couple weeks... I surely hope I can get my bike back up and running right in june.

Where's the best place to go for a timing chain?

Try E Bay

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