Not sure what it is about my 360s, but they have both blown the right side crank seal. It actually bends the steel retainers. None of my other bikes have done this. Just the two 360s. The symptoms are unmistakable. It suddenly runs like crap and literally pours white smoke out the exhaust.
The first occurrence was due to a backfire while trying to start it. The bike had CDI issues and I decided to convert it to points and condenser with parts taken from DT250B. Put in a new seal, straightened the bent retainers, and it has been fine now for several years.
The most recent occurrence was on my "new to me" 360 and it happened while riding it. I don't recall any backfire situation. It just simply fell flat on its face and fogged my entire yard to the point where you couldn't see thru the smoke. I should've taken a video because it was unbelievable.
If this everbhappens to you, don't make the mistake of continuing to ride thinking you might be able to clear it out with a good thrashing. Doing so will leave you low on crankcase oil. Don't ask me how I know.....