Holy Smoking Breather!!!

[fishmeok]

So we took the GS850G to the Minnesota State Fair yesterday- the first time I've really been stuck in traffic with the GS (heading for the motorcycle parking on Como Ave- those of you in MN know what I'm talking about...). After about 45 minutes of freeway riding and 10-15 minutes stop and go the bike started smoking like a mofo- I thought at first I had sprung a leak and was dripping oil on the exhaust. I'm sure the people behind me thought we were on fire...
I pulled over onto a side street and found it was all coming out the breather on the airbox. Since we were within 7 blocks of the fairgrounds I just parked it and we walked the rest of the way (which probably saved about 10 minutes- we beat the cars on Como to the entrance). After we returned several hours later the bike started fine and we rode home with no problem.

So I'm sure I was overheating and breaking down the oil, but has anyone else run into this? I was very surprised at the amount of white oil vapor the came out. My petcock doesn't leak (anymore) and I'm going to do an oil change this morning on general principle, to check for gas and burned oil. Any comments/suggestion?
Cheers
Mark

[mark]

I severely overheated my Honda 750 once in stop and go traffic. The smoke was incredible.....and very white......but it came out of the exhaust, not the breather tube. I was pumping oil, you seemed to have developed blow-by.

In my case, once the engine cooled down there were no more problems and at least from what I could tell, the bike ran as well as before.

Someone else might have better things to check, but I'd change the oil for sure and would double check valve clearances and maybe do a compression test to make sure everything is O.K. with the motor.

[Nessism]

Very strange story, both of them. I had no idea something like this could occur from overheating. It seems to me that in order for the crankcase breather to smoke so much there must have been massive blow by. In order to create such an event the rings must have been binding and not sealing properly. I agree with Mark in that a compression test is definitely in order to find out if there was any serious damage.

[49er]

So we took the GS850G to the Minnesota State Fair yesterday- the first time I've really been stuck in traffic with the GS (heading for the motorcycle parking on Como Ave- those of you in MN know what I'm talking about...). After about 45 minutes of freeway riding and 10-15 minutes stop and go the bike started smoking like a mofo- I thought at first I had sprung a leak and was dripping oil on the exhaust. I'm sure the people behind me thought we were on fire...
I pulled over onto a side street and found it was all coming out the breather on the airbox. Since we were within 7 blocks of the fairgrounds I just parked it and we walked the rest of the way (which probably saved about 10 minutes- we beat the cars on Como to the entrance). After we returned several hours later the bike started fine and we rode home with no problem.

So I'm sure I was overheating and breaking down the oil, but has anyone else run into this? I was very surprised at the amount of white oil vapor the came out. My petcock doesn't leak (anymore) and I'm going to do an oil change this morning on general principle, to check for gas and burned oil. Any comments/suggestion?
Cheers
Mark

Have a close look at the breather tract inside your airbox. After years of heavy condensation (many short trips), the narrrow tract rusts to such an extent as to eventually close itself off. When this happens, your engine starts to pressurise the crankcase forcing oil out of all sorts of places, including past the piston rings. Your tract may still be passing some air, hence the reason that it didn't smoke once the engine had cooled down!
This may be the cause of your smoke. I had a white vapour leaking out around the carbs/airbox area when my 850 had this problem. I cleaned the tract out with a piece of 1.6mm welding wire and plenty of patience.

[Regent]

So we took the GS850G to the Minnesota State Fair yesterday- the first time I've really been stuck in traffic with the GS (heading for the motorcycle parking on Como Ave- those of you in MN know what I'm talking about...).

I'm headed to the fair tomorrow, and I'm not familiar with the motorcycle parking area. What cross street is it near on Como? First year with a bike, and we usually just head up Snelling and get parking as close as we can.

[fishmeok]

It's usually right on the south side of the fairgrounds on Como Ave by the pedestrian bridge near the shuttle bus stops- you should probably check on line though, I think they moved it this year.
Cheers
Mark

[Guest]

If it's not the breather as 49er has suggested I would say your rings are a bit worn and getting sloppy at higher temps.

[fishmeok]

I'm thiunking it must be the rings as well- I cleaned out the breather and it had a bit of debris but wasn't blocked. My cylinders all get to about 120 within three compressions (50,75,120) but I don't have a leakdown tester to find out for sure.
Cheers
Mark

[Nerobro]

it's normal for engines to smoke a bit when they get hot. :-) Just change your oil, it'll be fine.

[bonanzadave]

It's usually right on the south side of the fairgrounds on Como Ave by the pedestrian bridge near the shuttle bus stops- you should probably check on line though, I think they moved it this year.
Cheers
Mark

Looks like its still there....



How was the Fair ? My grandson said Sunday was hot.

How was the oil level in the Bike ? Ive seen that happen with too much oil or if ya get some gas in the oil.