Blue Smoke

[steele_07]

What would cause blue smoke upon startup and first little bit AFTER it has sat for a few hours AFTER being ran and warmed up.  It doesn't smoke at all on the initial start up from cold.  I drive it approximately a mile first thing of a morning and it sits for 3-4 hours, and when I start it up after that is the point at which it smokes.  It is a 2012 Bennche Bighorn 500.  

[Travis]

What make engine is it?  Is it a fuel injected system?

[steele_07]

6 minutes ago, Travis said:

What make engine is it?  Is it a fuel injected system?

Hisun 471 cc and yes it is

[Travis]

I would say it's burning oil since it's blue smoke. But how you described it, after the 2nd start up it only blows the smoke, that's what confuses me.

It's not Diesel is it? If it is diesel, blue smoke means your injectors are bad/going out.

 

[steele_07]

16 minutes ago, Travis said:

I would say it's burning oil since it's blue smoke. But how you described it, after the 2nd start up it only blows the smoke, that's what confuses me.

It's not Diesel is it? If it is diesel, blue smoke means your injectors are bad/going out.

 

No it's gas.  My thoughts are that the oil needs to be warm to seep past the valve seals.  The only confusing part about that is the fact that it is warm when I park it for the night, therefore it should smoke on start up in the mornings, but doesn't.  And now that I think about it, the smoke on the 2nd start up actually doesn't start, or at least isn't noticeable, for a few seconds.  Then, it will smoke for 2-3 minutes and it's gone.

[Travis]

Hmmm,

 

4 hours ago, steele_07 said:

The only confusing part about that is the fact that it is warm when I park it for the night, therefore it should smoke on start up in the mornings, but doesn't.

Yeah, that is confusing., but it seeping past the seals, sounds likely.

 

[steele_07]

So what would be a ballpark estimate on getting those replaced.  I know I can get the parts for $9.  What would I be looking at labor wise?  I know it will vary by region, but i just need an idea.

[kenfain]

I wouldn't jump to a conclusion about the valve seals being the problem. Obviously they are a prime suspect, but if you're going to let a mechanic fix it...then let a qualified mechanic diagnose it also. When you tell a mechanic that you need new seals, then that's what you'll get. Even if that's not the problem. What if it's a cracked ring? Or a head gasket? 

   Have you pulled the plugs, and checked each one?

[Travis]

This sounds Similar to another thread on here, yet the other was a Kawi. But the smoke patterns seem the same. anyway, the problem was fuel getting into the crankcase.. MORE THAN LIKELY THIS IS NOT YOUR PROBLEM.

 

[steele_07]

2 hours ago, kenfain said:

I wouldn't jump to a conclusion about the valve seals being the problem. Obviously they are a prime suspect, but if you're going to let a mechanic fix it...then let a qualified mechanic diagnose it also. When you tell a mechanic that you need new seals, then that's what you'll get. Even if that's not the problem. What if it's a cracked ring? Or a head gasket? 

   Have you pulled the plugs, and checked each one?

That's a good point, but if you take it to any mechanic around here to diagnose, 2 seals will turn into a complete engine rebuild, new rearend, fuel pump, and tires.  

A head gasket or fuel in the crankcase would produce a different color smoke rather than blue right?

[kenfain]

Yes, I can understand how some mechanics can inflate a problem. But I'm just pointing out that the proper diagnosis is everything. Just replacing suspect parts will only lead to frustration. I've been there before.

   You can certainly follow a gut feeling, and replace what you think the problem is. Leaking valve guides seems reasonable, considering the symptoms. You might get lucky. In answer to the time it takes to change out the valve seals. It should be about three hours or so. That's assuming he's pulling the head, to change them. Some people have used air pressure to hold the valve in place while changing out those seals. I've also heard of stuffing rope down in through the spark plug hole to accomplish this. It's a less invasive approach, and saves money on parts. 

 

[ChadSummers]

I have a similar situation with a Massimo 500 that I recently bought used... Didn't realize it smoked (blue) when I purchased and now notice it does so primarily under load. In low gear or running hard.... Other than that, cranks easy and runs good. Checking compression today... Any ideas?

 

Thanks

[Dan B]

9 hours ago, ChadSummers said:

I have a similar situation with a Massimo 500 that I recently bought used... Didn't realize it smoked (blue) when I purchased and now notice it does so primarily under load. In low gear or running hard.... Other than that, cranks easy and runs good. Checking compression today... Any ideas?

 

Thanks

If it's blue smoke all the time (sitting at idle & while driving), it's most likely the oil control rings.  A compression test won't expose that problem.  But if the oil control rings are bad, it's likely that the compression rings are also bad (might show low compression).  If only under heavy acceleration, it's the valve stem seals.  The vacuum created under heavy acceleration can cause oil to be drawn past worn valve stem seals.  This info is from many websites on automobile engines.  ATV/UTV engines aren't much different.

[ChadSummers]

Thanks. It does seem to be primarily during load or heavy acceleration.  Also seems like after the engine got hot it got much better. 

[Travis]

@ChadSummers   Do you know what Compression specs are?

[ChadSummers]

This is what I got from service manual 

standard : 188.31 psi

minimum: 163.57 psi

maximum: 210.5 psi