2015 WR 250 F blowing smoke

I've got a 2015 WR that is starting to blow smoke from the pipe.  it's got about 150 hours and has never had engine open/valves checked.  it still runs great and starts without any issues.  My question is, if this is a ring issue and I have to open the engine, what else should I do?  Is there a new piston design that I should install?  Today, I rode a 2017 KTM 250 XCF and it has noticeably more power.  I want that. I've already got an FMF pipe and GYTR computer with a very strong tune.  Any help or suggestions would be appreciated.   thanks. 

Edited by Tony T
added more info.

Blue smoke?

White smoke?

Black Smoke?

A little more learning and diagnostics needed.  

Blue smoke is oil.  Could be simple as Valve seals, or serious as total rebuild.  A leak down test is needed, then go from there.

White smoke is water vapor.  Also exhaust will smell sweet or like antifreeze.  Leaking head gasket is the reason, new head gasket is the fix.

Black smoke is gas. Mixture is too rich.  Could be as simple as fuel screw needs adjusted in, or is missing.  (yes, we lost two on two different bikes)

12 hours ago, ronbuell said:

Blue smoke?

White smoke?

Black Smoke?

A little more learning and diagnostics needed.  

Blue smoke is oil.  Could be simple as Valve seals, or serious as total rebuild.  A leak down test is needed, then go from there.

White smoke is water vapor.  Also exhaust will smell sweet or like antifreeze.  Leaking head gasket is the reason, new head gasket is the fix.

Black smoke is gas. Mixture is too rich.  Could be as simple as fuel screw needs adjusted in, or is missing.  (yes, we lost two on two different bikes)

it's blue smoke.

As said, if its blue smoke it could be valve seals (@150hrs it is a bit unlikley) or could be a broken ring or scored cylinder from dirt ingress or a blocked breather or even way overfilled on engine oil

 

There is an updated piston which was fitted to the YZ250F from 2014 & WR from 2016 onwards (1SM116310100) and I believe is a straight drop into your 2015 WR

The YZ250F got another new piston for 2016 (1sm116311000), and the YZ250FZ then got it in 2017 but not the WR

Don't know if these are for power or reliability

 

There's the option of a 276 big bore which apparently gives it a lot more bottom end torque if the piston/cylinder is damaged

Edited by GuyGraham

Smoking when hot or cold. They all seem to smoke a bit cold in my experience. 

Do you have the GYTR competition kit installed? 

The KTM is a top end power bike, the Yamaha power is much more usable. 

What tune is your Yamaha running?

Yes they do smoke a little on start up for the first 30-40 hrs then stop

its been blowing smoke every time when starting and I'm getting buddies tell me that they see it when riding behind me.

yes, I have the competition kit and am running the tune pictured. 

thanks again for the help.

IMG_2982.jpeg

Edited by Tony T

I would start your diagnostics with checking the valve clearances. 

Valves in or out of spec aint gonna cayse blue smoke

If your buddies can smell/see it when behind then its timw for the head to come off

1 minute ago, GuyGraham said:

Valves in or out of spec aint gonna cayse blue smoke

 

It could indicate worn valve guides and valve stem seals which seams like it would drop oil into the combustion chamber to me anyway. 

Is there a noticeable amount of oil loss in the sight glass between changes? 

KTM will feel more powerful cause it 'is' more powerful. It's also 20+lbs lighter... 

Sounds like you're burning oil, most likely from a burnt out valve seal. If you search around the forums it seems to be a somewhat common issue with these bikes. 

7 hours ago, Tony T said:

it's blue smoke.

Then you have a couple of options.  You could just do the valve seals and see if that fixes it.  Or you could to the valve seals and put a piston/ring set in.  Frankly, when I do a top end, I don't do just valve seals, but also replace the valves as well.  Expensive, so weight the cost.  If you have more diagnostics available, use them.

13 minutes ago, ronbuell said:

Then you have a couple of options.  You could just do the valve seals and see if that fixes it.  Or you could to the valve seals and put a piston/ring set in.  Frankly, when I do a top end, I don't do just valve seals, but also replace the valves as well.  Expensive, so weight the cost.  If you have more diagnostics available, use them.

Just FYI, I didn't have blue smoke but had low compression on my 2016 KX250F. I was curious on how much for new valve installation, seals, guides, and valve seat cutting. $350 for labor and $350 for parts so it's a $700 refurbished head cost which of course doesn't include the top end. Most riders can do the top end themselves and the parts prices are around $200. 

 

41 minutes ago, shrubitup said:

Just FYI, I didn't have blue smoke but had low compression on my 2016 KX250F. I was curious on how much for new valve installation, seals, guides, and valve seat cutting. $350 for labor and $350 for parts so it's a $700 refurbished head cost which of course doesn't include the top end. Most riders can do the top end themselves and the parts prices are around $200. 

 

For the Yamaha WR/YZ250F 02-05 steel frames, Valves are about $55 ea. (5 for $255, but the last set I bought was $125. Tried an off brand, not OEM) I have not had to replace the valve guides in any of mine.  I have replaced cam chains, sliders, oil pumps, pistons/pins/clips/rings, gasket sets, and shim set to re-shim the cams.  Plan on $850... more if someone else does the labor.

KTM will feel more powerful cause it 'is' more powerful. It's also 20+lbs lighter... 

The ktm will wear out too and easily cost twice what the yamaha does to rebuild. Then you need to ask yourself how they can be 20lbs lighter? Also plan on$$$$ to fix the suspension.
KTM will feel more powerful cause it 'is' more powerful. It's also 20+lbs lighter... 

The ktm will wear out too and easily cost twice what the yamaha does to rebuild. Then you need to ask yourself how they can be 20lbs lighter? Also plan on$$$$ to fix the suspension.
21 minutes ago, motocrotts said:


The ktm will wear out too and easily cost twice what the yamaha does to rebuild. Then you need to ask yourself how they can be 20lbs lighter? Also plan on$$$$ to fix the suspension.
The ktm will wear out too and easily cost twice what the yamaha does to rebuild. Then you need to ask yourself how they can be 20lbs lighter? Also plan on$$$$ to fix the suspension.

OK bud, whatever you have to tell yourself so you can sleep better at night... 

OK bud, whatever you have to tell yourself so you can sleep better at night... 

Please explain whats not true in that statement.

Please explain whats not true in that statement.

Exactly what i expected.

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