Engine smoke on startup

[KBear]

Hey guys. 2016 RC with less than 3,000 mile on it. A couple times now when I start the RC after I haven't ridden in a week or so it smokes on startup until it warms up. This has happened twice now, but not in a row. One day I started it to ride and no smoke a couple weeks later I start it to ride and it smokes until it warms up. Any thoughts? Now, at the very end of last summer I had a KTM mechanic check my oil level while at the shop and I think he over filled it. I haven't ridden the bike that much since then. Could this be the issue? I check the oil often and it doesn't look over full to me. Not sure why it would smoke on startup this summer. This has not happened before. Any help or ideas would be great.

 

[ReidMcT]

Are you sure it is smoke and not water vapor? Vapor disappears soon after leaving the tailpipe; smoke hangs around.

If it is smoke, and it is blackish, then it indicates a very rich mixture. Unlikely in a computer-controlled, injected bike.

If is bluish white smoke, then it is oil burning. Such smoke happening only on startup and only after sitting for a good while indicates bad valve stem seals or worn valve guides; unusual in a bike with so few miles, but not impossible.

Are you certain you are checking the oil level according to the user manual instructions? You seem a bit vague in your statement about that. The level should be between the upper and lower marks when the bike is upright on a level surface about a minute after shut-down.

 

[KBear]

ReidMcT - Yes, I do check the oil on a regular basis and I do have enough oil showing in the sight glass per owner's manual (maybe too much I think at times). The smoke is whitish blue (more white than blue) and yep it's smoke. I can smell and see it on initial startup. This has only happened a couple times thus far and it's not happened before. I don't ride this bike hard that's for sure, I baby it. I have other bikes I ride much more often. Just seems sorta odd that smoke would be coming from the exhaust considering how well I take care of this machine. Different to me.

 

[ReidMcT]

I do have enough oil showing in the sight glass per owner's manual (maybe too much I think at times).

That's what I was hung up on: It sounds as if you may have too much oil... but you're not sure. The level should be between the marks, neither above the top mark nor below the bottom mark. Best is right in the middle.

Anyway it does sound possible that you have bad valve stem seals. Parts do sometimes fail early.

But it also could be that an overfilled crankcase caused an unusual amount of oil to end up in the airbox via the crankcase breather. That's why I asked about the oil level.

Have you checked the airbox drain? The tube with a plug in it. The maintenance schedule calls for it to be checked at least annually.

 

[KBear]

That's what I was hung up on: It sounds as if you may have too much oil... but you're not sure. The level should be between the marks, neither above the top mark nor below the bottom mark. Best is right in the middle.

Anyway it does sound possible that you have bad valve stem seals. Parts do sometimes fail early.

But it also could be that an overfilled crankcase caused an unusual amount of oil to end up in the airbox via the crankcase breather. That's why I asked about the oil level.

Have you checked the airbox drain? The tube with a plug in it. The maintenance schedule calls for it to be checked at least annually.

You could very well be right. I may have too much oil. I will check the airbox drain today for sure!! Yes, I did check the airbox drain Spring of last year but did not check it Spring this year I was in the middle of a move. Now that things have calmed down a bit I have more time to do that.

 

[KBear]

Okay, started the RC up this afternoon and no smoke. If there was it was very very little. Checked the airbox drain as well, nothing, bone dry. One thing I did notice today. Condensation coming from the weep hole at the bottom of the exhaust pipe. Now, I live in a pretty arid climate but the humidity has been a bit higher for the last few days and I did ride the RC yesterday so that could have been from the ride yesterday.

What has be baffled is one mid morning on startup it will smoke. A day or two later around the same time on startup no smoke. I started it yesterday and smoke. I started it this afternoon no smoke. I'm not understanding this one.

 

[KBear]

I'm convinced the RC has too much oil in the crank case.

 

[m3hl]

I'm convinced the RC has too much oil in the crank case.

I have the EXACT same symptoms on my bike. Almost always smoke on start up. Since its a track bike, it only gets ridden rarely. I suspect valve seals, but my bike only has like 5k miles on it also.