Exhaust smoke on warm ups???

I recently noticed that while my 03 wr450 is warming up, with "choke" on, that the bike occasionally blows white smoke out of the exhaust. (oil?) Its not constant, it only does it four or five times, for a second or so, while that choke thing is engaged. When I take choke off and idle normally it doesn't blow any smoke, but when I crack the throttle it does. After a couple miles of riding, it doesnt do it at all anymore, idling or cracking the throttle. Only happens at the very beginning ater starting it.

Whats going on here? Am I screwed? I know that I need a valve adjustment in a little bit, its not bad at all yet. Could that be it?

White smoke is water vapor

Blue smoke is oil

Black/gray smoke is fuel

Probably some condensation burning off. When you shut the bike down the exhaust is hot. Humid air flows in the exhaust and then the water vapor condenses on the metal and is absorbed into the packing. Heat it up by starting the bike and the water turns to vapor again...

White smoke is water vapor

Blue smoke is oil

Black/gray smoke is fuel

Probably some condensation burning off. When you shut the bike down the exhaust is hot. Humid air flows in the exhaust and then the water vapor condenses on the metal and is absorbed into the packing. Heat it up by starting the bike and the water turns to vapor again...

Oil smoke doesn't always look blue, white smoke could be oil either the valve stem seals or rings.

You really think its that simple? just water vapor? I hope thats it haha

And I hope its not rings.

What do you guys reccommend I do?

It only does it at the beginning. And its not the whole time while warming up. just goes in short spurts, maybe 4 - 5 times for a quick second.

You really think its that simple? just water vapor? I hope thats it haha

And I hope its not rings.

What do you guys reccommend I do?

It only does it at the beginning. And its not the whole time while warming up. just goes in short spurts, maybe 4 - 5 times for a quick second.

Take the can off and try it...see if you get anything coming out of the pipe itself....or put another can on.

It could be that since the piston is still cold it hasn't fully seated into the cylinder and so a little bit of oil is allowed past it and burns up? Just an ideal.

come on its a 03, its probably a combination of piston/rings valve seats, valve seals and valves. When was the last time it was rebuilt with piston/ rings and valves? ...... exactly.....

Take the can off and try it...see if you get anything coming out of the pipe itself....or put another can on.

I will try that..... Thank you!

It could be that since the piston is still cold it hasn't fully seated into the cylinder and so a little bit of oil is allowed past it and burns up? Just an ideal.

Interesting...... could be since it is like 30 degrees where i live right now and has been pretty cold. Never noticed it in the warm months.....Thanks!

come on its a 03, its probably a combination of piston/rings valve seats, valve seals and valves. When was the last time it was rebuilt with piston/ rings and valves? ...... exactly.....

Hey come on now, be nice!! I dont want to hear that stuff haha. I cant afford to have it rebuilt right now! Your right, it is an 03 and I know its old, but its never given me any problems besides the electric start so I'm hoping its nothing too expensive like what yer saying...... Im having the valves looked at and adjusted very soon so we will find out I guess. And the bike has never been rebuilt as far as I know. But it barely gets ridden and not hard either. I'm easy on her....

The smoking is happening at a time when the Vacuum is very high (closed throttle and high idle) and the engine is cold which means the piston and ring tolerances are farthest apart.

This is a classic sign of wear. Don't panic ride it. just start planning a top end rebuild.

I was a betting man I would bet you that your spark plug is dark brown indicating oil consumption.

The smoking is happening at a time when the Vacuum is very high (closed throttle and high idle) and the engine is cold which means the piston and ring tolerances are farthest apart.

This is a classic sign of wear. Don't panic ride it. just start planning a top end rebuild.

I was a betting man I would bet you that your spark plug is dark brown indicating oil consumption.

I'll have to check my spark plug to see but you are probably right! Thanks!!

Valve seals!

Valve seals!

Really?!!!? How bad is that on the pocket book? having it done at a shop that is......

I know for sure it's oil and not water vapor. smells like oil.

My '98 does that; I've checked the valves, but no rebuild. Since I'm old and slow, and it has more power than I can use.

It seems to me that you are worring too much and that this is giving you a lot of trouble. I think I can solve most of it. Here's what you do:

1. Find the title or create a bill of sale.

2. Crate the bike (don't forget to drain the fuel).

3. Send everything to me.

No more worries on your end and I'll upgrade. :excuseme:

My '98 does that; I've checked the valves, but no rebuild. Since I'm old and slow, and it has more power than I can use.

It seems to me that you are worring too much and that this is giving you a lot of trouble. I think I can solve most of it. Here's what you do:

1. Find the title or create a bill of sale.

2. Crate the bike (don't forget to drain the fuel).

3. Send everything to me.

No more worries on your end and I'll upgrade. :excuseme:

Hahaha nice!! Thats the easy way out! I think I'll have the shop do the valves and make sure everything is good there. If that doesnt fix it then I'll crate it up haha.

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