Jump to content
Sign in to follow this  

06 crf250r burning oil? need help!

Recommended Posts

alright well i have an 06 crf250r and i had it fully rebuilt, top and bottom end... i broke it in and it was running good until it randomally started smoking, bluish smoke burning oil... so i have changed the gas,replaced the rings, replaced the valve seals, replaced the right crank seal, and have checked the valves, cylinder, and valve seats and they are all good. seats are sealing perfect... so does anyone have any other ideas what it is? i just got done replacing the right crank seal and thought it was good to go then i started smoking again... also it is mostly just smoking after it is warm when you give it gas....and no i dont have premix in its... so any other ideas of what it could be? im about ready to split the cases to replace the left crank seal if that could be it....let me know what you guys think, i really cant figure this out... Thanks!

Share this post


Link to post
Share on other sites

well the valve seals were the first thing we replaced... and just got done with replacing rings... and it still smokes... also the first time we tore the engine down there was some water on the top of the piston... so we replaced the gasket as well but it still smokes

Share this post


Link to post
Share on other sites

im hearing some people say they think the compression ring could be in backwards, which makes since but why would the bike run good for 20 hours and then randomally start smoking if the ring was upside down? anyone think that the left crank seal could be the cause?

Share this post


Link to post
Share on other sites

List for a smoking engine possibility

First of all, be sure your burning oil, not your coolant.

Coolant gonna smoke white and smell sugar

Oil gonna burn blue

Coolant burning possible cause in order

Wrong head gasket

Warped cylinder head surface

Warped cylinder top surface

Cracked cylinder water pass

Cracked cylinder head

Wrong or missing ORing

Oil burning possible cause in order

Wrong or missinstaled ring (side and alignement)

Scared cylinder liner

Wrong piston

Wrong valve seal

Wrong valve guide

Wrong valve steam

Wrong head gasket

Warped cylinder head surface

Warped cylinder top surface

Wrong piston axe

Cracked cylinder head

Cracked cylinder in oil pass

Clogged PCV hose

Wrong Crankshaft rod

Wrong Crankshaft rod bearing

Wrong Crankshaft cage

Wrong Crankshaft bearing

Cracked crankshaft case

You CAN'T have another reason

Edited by DarkCRF

Share this post


Link to post
Share on other sites
im hearing some people say they think the compression ring could be in backwards, which makes since but why would the bike run good for 20 hours and then randomally start smoking if the ring was upside down? anyone think that the left crank seal could be the cause?

So

Backward install ring is a good guest in our case. Carefully inspect your head and cylinder for crack and really check the contact surface for warpage.

No, your left crank seal can't be the cause.

Share this post


Link to post
Share on other sites

yes it is burning oil. its blue. and the valve seals i know are good, cylinder is good, crank is good, bearings are good, there are no cracks, piston and rings are the right ones. so you dont think that the ring being flipped wrong would cause it? the compression ring?

Share this post


Link to post
Share on other sites
List for a smoking engine possibility

First of all, be sure your burning oil, not your coolant.

Coolant gonna smoke white and smell sugar

Oil gonna burn blue

Coolant burning possible cause in order

Wrong head gasket

Warped cylinder head surface

Warped cylinder top surface

Cracked cylinder water pass

Cracked cylinder head

Wrong or missing ORing

Oil burning possible cause in order

Wrong or missinstaled ring (side and alignement)

Scared cylinder liner

Wrong piston

Wrong valve seal

Wrong valve guide

Wrong valve steam

Wrong head gasket

Warped cylinder head surface

Warped cylinder top surface

Wrong piston axe

Cracked cylinder head

Cracked cylinder in oil pass

Clogged PCV hose

Wrong Crankshaft rod

Wrong Crankshaft rod bearing

Wrong Crankshaft cage

Wrong Crankshaft bearing

Cracked crankshaft case

You CAN'T have another reason

yes it is burning oil. its blue. and the valve seals i know are good, cylinder is good, crank is good, bearings are good, there are no cracks, piston and rings are the right ones. so you dont think that the ring being flipped wrong would cause it? the compression ring?

Yeah maybe, but stop doing supposition and inspect EVERYTHING carefully. Start by the beginning.

Share this post


Link to post
Share on other sites

so im starting to think its the rings/cylinder.. cause i didnt have the cylinder honed and i didnt do the ring gap.

Share this post


Link to post
Share on other sites
so im starting to think its the rings/cylinder.. cause i didnt have the cylinder honed and i didnt do the ring gap.

Pull the head and cylinder and look for a broken ring. Its possible that your ring end gap was too small and broke one or more of your rings. Or possibly your oil rings are installed incorrectly, or you didnt stagger your ring end gaps properly.

Share this post


Link to post
Share on other sites

What Keith said or the exhaust valve guides. The exhaust valve guides are real common to go bad, especially the older bikes with some hrs on them.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×