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Puff of Smoke


GDD

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Hi,

My '03 RT blows a puff of smoke after starting if I have not ridden it for a week or so. Is this normal (my first BMW) or should I be worried?

Regards,

Grant.

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Yup, pretty normal. Particularly if you use the side stand most of the time. A puff-o-smoke is a character trait of the boxer motor as a small amount of oil can sneak past a valve guide or the rings because oil just sits there in a flat motor. On the side stand the left calendar is down hill allowing oil to pool in the head and flow up the cylinder wall past the rings. /5 Airheads were some of the most effective yard insect foggers ever created. eek.gif If you want reduce, or possibly eliminate this, try using the center stand almost exclusively. No worries mate thumbsup.gif

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Yup, pretty normal particularly if you use the side stand most of the time. A puff-o-smoke is a character trait of the boxer motor as a small amount of oil can sneak past a valve guide or the rings because oil just sits there in a flat motor. On the side stand the left calendar is down hill allowing oil to pool in the head and flow up the cylinder wall past the rings. /5 Airheads were some of the most effective yard insect foggers ever created. eek.gif If you want reduce, or possibly eliminate this, try using the center stand almost exclusively thumbsup.gif

 

Thanks very much, I'm relieved.

You are absolutely correct, it's on the side stand all the time.

Great forum, a wealth of knowledge. thumbsup.gif

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Yup, pretty normal. Particularly if you use the side stand most of the time. A puff-o-smoke is a character trait of the boxer motor as a small amount of oil can sneak past a valve guide or the rings because oil just sits there in a flat motor. On the side stand the left calendar is down hill allowing oil to pool in the head and flow up the cylinder wall past the rings. /5 Airheads were some of the most effective yard insect foggers ever created. eek.gif If you want reduce, or possibly eliminate this, try using the center stand almost exclusively. No worries mate thumbsup.gif

 

I take some exception to Paul's comments here....

 

While smoke at cold start is frequent, it is NOT normal. Oil seeping into the downhill cylinder when overnighted on the side stand can cause minor smoke at cold start. This might mean your oil is no longer holding up regarding viscosity.

 

I would question the oil grade and brand you are using as well as oil change intervals.

 

Do you know when the oil was last changed? What brand and grade were used?

 

Also, check you spark plugs for deposits. If the oil is not getting along with the engine, it may show up on spark plugs.

 

Sorry but, I would investigate a bit further.

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Jim VonBaden
Yup, pretty normal. Particularly if you use the side stand most of the time. A puff-o-smoke is a character trait of the boxer motor as a small amount of oil can sneak past a valve guide or the rings because oil just sits there in a flat motor. On the side stand the left calendar is down hill allowing oil to pool in the head and flow up the cylinder wall past the rings. /5 Airheads were some of the most effective yard insect foggers ever created. eek.gif If you want reduce, or possibly eliminate this, try using the center stand almost exclusively. No worries mate thumbsup.gif

 

Spot on!

 

The oilheads, and K-bikes can all puff a bit of smoke. K-bikes much more than a puff.

 

I too use my sidestand nearly exclusively, and even on my new 12GS occasionally get a bit of smoke if the bike has been sitting a few days.

 

No worries at all.

 

Jim cool.gif

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No_Twilight

Sidestands are not all created equal. My R1100RS leans WAAAAAAAY over on the sidestand. I cured the smoke problem by keeping a piece or 3/4" thick wood on the floor to land my sidestand on. It still leans over more than some bikes but that was enough to keep it from smoking. If you try this make sure you don't overdo it making the bike unstable away from the sidestand where it could fall and damage the paint or worse land on someone you like.

 

--Jerry

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I take some exception to Paul's comments here....

...and I take some exception to yours! grin.gif

 

While smoke at cold start is frequent, it is NOT normal. Oil seeping into the downhill cylinder when overnighted on the side stand can cause minor smoke at cold start. This might mean your oil is no longer holding up regarding viscosity.

First, since this is something that all boxers and flat-4 K-bikes do from time to time, it has to be considered (by definition) to be "normal".

 

Second, oil viscosity has nothing significant to do with the problem. The problem is caused when the motor stops and oil that has puddled in one of the cylinders (usually as a result of being on a side stand) is SUCKED past the rings, because that piston happened to stop at a point where the valves were closed and some suction was created. It is also influenced by the ring gap; if the gap is at the bottom, oil can more easily get past the rings (normally, all rings rotate slowly when the motor is running).

 

Newer K-bikes (I think starting at the 4-valve K's) had their oil rings pinned so the gap could not be at the bottom. This reduces the possibility of sucking oil past the rings. I don't know if they did this to boxers.

 

I would question the oil grade and brand you are using as well as oil change intervals.

This makes no significant difference. For example, my K-bike occasionally puffs oil when starting. There is no difference whatsoever in the amount of smoke, or the frequency that it happens, whether I have just changed the oil, or whether it has been in there for the better part of a year. Similarly, the viscosity of oil I use makes no apparent difference to this either.

 

Also, check you spark plugs for deposits. If the oil is not getting along with the engine, it may show up on spark plugs.

In total, there is VERY little oil actually consumed. In any event it will easily be burned off once the motor is running, and no matter what is on the plugs, it won't have any affect on how much oil is puffed out when starting. Spark plugs and oil burning are not connected.

 

So, in a word... "They all do that"

 

Bob.

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I take some exception to Paul's comments here....

...and I take some exception to yours! grin.gif

 

While smoke at cold start is frequent, it is NOT normal. Oil seeping into the downhill cylinder when overnighted on the side stand can cause minor smoke at cold start. This might mean your oil is no longer holding up regarding viscosity.

First, since this is something that all boxers and flat-4 K-bikes do from time to time, it has to be considered (by definition) to be "normal".

 

Second, oil viscosity has nothing significant to do with the problem. The problem is caused when the motor stops and oil that has puddled in one of the cylinders (usually as a result of being on a side stand) is SUCKED past the rings, because that piston happened to stop at a point where the valves were closed and some suction was created. It is also influenced by the ring gap; if the gap is at the bottom, oil can more easily get past the rings (normally, all rings rotate slowly when the motor is running).

 

Newer K-bikes (I think starting at the 4-valve K's) had their oil rings pinned so the gap could not be at the bottom. This reduces the possibility of sucking oil past the rings. I don't know if they did this to boxers.

 

I would question the oil grade and brand you are using as well as oil change intervals.

This makes no significant difference. For example, my K-bike occasionally puffs oil when starting. There is no difference whatsoever in the amount of smoke, or the frequency that it happens, whether I have just changed the oil, or whether it has been in there for the better part of a year. Similarly, the viscosity of oil I use makes no apparent difference to this either.

 

Also, check you spark plugs for deposits. If the oil is not getting along with the engine, it may show up on spark plugs.

In total, there is VERY little oil actually consumed. In any event it will easily be burned off once the motor is running, and no matter what is on the plugs, it won't have any affect on how much oil is puffed out when starting. Spark plugs and oil burning are not connected.

 

So, in a word... "They all do that"

 

Bob.

 

First, since this is something that all boxers and flat-4 K-bikes do from time to time, it has to be considered (by definition) to be "normal".

 

No they don't. I have routinely left my '01 boxer on the side stand for weeks. I have never experienced so much as a whif of oil smoke at start up.

 

Also, I disagree that rings rotate in their grooves as the engine runs.....I have dissassembled many engines only to find the rings in the identical orientation I had installed them in.

 

The cylinders in BMWs are Nikasil plated....a very hard cylinder surface that takes many miles to thoroughly bed in.

 

A BMW engine with less that 10,000 miles will use oil due to the scratch honing BMW applies to the walls. After the engine is thoroughly bedded in, oil has no path to the combustion chambers if valve guides are in spec.

 

Spark plugs are the only thing that can tell you what's going on the the cylinders during combustion short of a tear down. Plugs tell you about timimg, mixture, ring condition, too much heat and too cold....about the only thing a sparkplug won't do is talk to you.....that's why you have to read them.

 

Modern oils with ZDDP tend to form a glassy deposit on surfaces, especially under the extreme heat of combustion. Reading your plugs can tell you volumes regarding engine conditions and about the quality of the oil in your engine.

 

Finally, there is no circumstance where there is suction in the cylinder of a 4-stroke engine that is at rest.

 

But, I do agree with you that the oil smoke at start-up is of little concern....every see a big P-W radial aircraft engine at cold start........they consume as much as a quart of oil as they fire.

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There is a very easy and cheap fix to this 'issue'. With the engine off, mount the bike. Place key in ignition and switch on. Ensure bike is in neutral, side stand up and clutch pulled in. Engage cold start lever and press starter, ride off, releasing cold start lever after a few minutes.

This does not stop puffs of smoke, you just never see them as they are out of sight, so you don't worry about it.

 

Andy thumbsup.gif

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There is a very easy and cheap fix to this 'issue'. With the engine off, mount the bike. Place key in ignition and switch on. Ensure bike is in neutral, side stand up and clutch pulled in. Engage cold start lever and press starter, ride off, releasing cold start lever after a few minutes.

This does not stop puffs of smoke, you just never see them as they are out of sight, so you don't worry about it.

 

Andy thumbsup.gif

 

Andy, you've got it right. Thank you.

 

Good weekend to all....

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Without trying to beat this to death....

Also, I disagree that rings rotate in their grooves as the engine runs.....I have dissassembled many engines only to find the rings in the identical orientation I had installed them in.

And I have found mine in different locations. But neither of these matters. BMW wouldn't have pinned rings if they don't rotate. Anyway, my source for this information was in one of my old mechanical engineering texts so I put my trust in that, I guess.

 

Bob.

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Without trying to beat this to death....

Also, I disagree that rings rotate in their grooves as the engine runs.....I have dissassembled many engines only to find the rings in the identical orientation I had installed them in.

And I have found mine in different locations. But neither of these matters. BMW wouldn't have pinned rings if they don't rotate. Anyway, my source for this information was in one of my old mechanical engineering texts so I put my trust in that, I guess.

 

Bob.

 

Bob,

 

Isn't it great that you and I can agree or disagree across a medium where 1000s of folks can view our debate and weigh in or not if they feel so compelled.

 

I respect your wisdom and now, face the north and sing "Oh Canada" (I'm married to a Canadian gal so, I am compelled to show due respect to all Canadians.

 

Fare well...good weekend. I bow to your wisdom.

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I respect your wisdom and now, face the north and sing "Oh Canada"

Step slowly away from that podium!! Don't sing that! As a Canadian, I can say that to me, this is the silliest anthem I've heard (at least that I've heard and can understand the words of).

 

I bow to your wisdom.

Assuming, of course, that I have any.

 

Bob.

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No_Twilight
There is a very easy and cheap fix to this 'issue'. With the engine off, mount the bike. Place key in ignition and switch on. Ensure bike is in neutral, side stand up and clutch pulled in. Engage cold start lever and press starter, ride off, releasing cold start lever after a few minutes.

This does not stop puffs of smoke, you just never see them as they are out of sight, so you don't worry about it.

 

Andy thumbsup.gif

 

Unfortunately, I usually start my bike as I'm backing it out of the garage so the first I notice it is as I roll into the plume!!!!

 

Cheers,

Jerry

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There is a very easy and cheap fix to this 'issue'. With the engine off, mount the bike. Place key in ignition and switch on. Ensure bike is in neutral, side stand up and clutch pulled in. Engage cold start lever and press starter, ride off, releasing cold start lever after a few minutes.

This does not stop puffs of smoke, you just never see them as they are out of sight, so you don't worry about it.

 

Andy thumbsup.gif

 

Unfortunately, I usually start my bike as I'm backing it out of the garage so the first I notice it is as I roll into the plume!!!!

Right! In that case, add the following to the instructions....

"First, don gas mask".

 

Bob.

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