tri z smoke

[jmax857]

Went for a ride today, and we were riding some trails, not really running the bike hard or anything we pulled out on a straight and me and my buddy dragged a couple times and on the last run he told me my bike started smoking at the end out of the run out the exhaust. The snoke was whitish blue ,but it reaked almost like a burning plastic smell not sweet like antifreeze, although I didn't have any coolant and I'm running about 30 percent ccoolant and 70 water. I stopped the bike and let it sit for a minute and it doesn't smoke anymore. Trucked it home and same thingg it doesn't smoke.
The part I think is wierd is that it only smoked for a brief period my coolant is high, and it didn't smell like coolant.
Anytimme I ever blew aa head gasket it smoked after just aas much after it cooled down, I have a vesrah gasket right now and I think I'm going to swtch out to a yamaha anyway,
Besides a head gasket, what else could it be? It juust didn't seem like a head gasket to me but I don't really think it could. Be anything else.
I'm also not running a thermostat, no coolant running out the overflow, and I rebuilt the engine within the last 15 hrs or so.

[shortline10]

I have seen were the tail pipes hold oil and the excessive heat from a few drag races made the oil burn were it normally wouldnt have . Wouldnt hurt to retork the head gasket as well ....

[jmax857]

Would that explain the smell? Kind of like burning fiberglass or plastic?I have a full dg exhaust. Can I still get yamaha oem gaskets?
I would hate to blow my new top end.
Also the exhaust kept bellowing smoke even after I shut it off, to the point I was worried
There was somethhing on fire in ther and I plugged the end of it.

[TimSr]

I've been riding TriZs since 1990, and I have never seen a blown head gasket result in excessive smoke. The cylinder compression is far higher than the cooling system pressure, and the first symptom of a blown head gasket is coolant and steam blowing out the overflow.
My first suspicion based on the continuous smoke after its off is is that you typically putt around trails and have left a nice tar coating throughout the exhaust, and when you decided open it up on a long straight, your exhaust started getting hot, and you started burning off that tar coating, and yes, it will continue to smoke until it cools down, and it will smell nasty. I had the same thing happen when I put my trail machine on an oval track. You can soak and clean the pipe with solvents and get limited results, but I ended up burning mine out. Also, there is a good chance the packing in your silencer is saturated with oil, and needs repacked as well. This is a common side affect from the school of thought that says running 20:1 fuel mix with conventional oil is a good idea without leaning it out enough to actually burn it.

Other causes for continuous excessive smoke - too much oil to gas fuel mix.

Leaking crank seal on the right side which can be intermittent at times, vary with RPMs or be continous.

[jmax857]

Thanks for the info.
I'm running 32:1 with ipone
Brand new crank seal, it sounds reaasonable it could be a seal aswell, I suppose a leakdown test could give me the answer. One thing I noticed is I used aftermarket seals from a member on here and they seemed shallower than stock. Maybe I will keep in mind if it happens again to pay more attention to the smell.
This haappened on my cr a long time back, and the smoke from the bad seal was black? ,

[jmax857]

On a side Note, I have an errratic idle, it goes up And down.
I know thhat is a sign of a bad stator side crank seal. I have a 38mm keihin pj carburetor, and I had this same problem with it before I rebuilt the engine, I assumed becausee the pilot is too fat

[adcotton]

I think surging is from lean running. Hence stator side leak, pulling in air.

[Afrothunderkat]

"my bike started smoking at the end out of the run out the exhaust"

Its a 2 stroke. Last time I checked, smoke came out of my exhaust.


All kidding aside, My RM 250 had a clutch side seal leak. It smelled like old hamburgers, switched it out and no more issues. Now it smells awesome. Got to love KLOTZ!

[jmax857]

Is there only the one vent for the gearbox? The one on the lefthand side at the base of the cylinder, also where should it be routed too?