CM91 white smoke from cylinder head

[jeff kjoller]

So I finally have my CM91 starting on first kick. No more leaks from the carb. Everything is adjusted and it is running smoothly. BUT, after it runs for a minute or so, white smoke starts coming out near the cylinder head. I can't find exactly where but its wisps of white smoke like you would see coming from a cigarette burning.
Is the gasket going bad?

 

[kirrbby]

If the smoke is puffing out with every stroke of the piston, you have a problem. But if it's just oil or something burning off of the outside of the exhaust, cylinder, or head...it should stop after it all burns off. If it persists, you have a problem.

 

[jeff kjoller]

you can sort of see the smoke in this you tube video. It's faint but there towards the right side of the cylinder head. You will need to enlarge the viewer to see it.

 

[69ST]

Very hard to see. As best I can tell, it looks like it's coming from the main oil passage...getting past the sealing washer & acorn nut. That's unusual. Check the crankcase breather. It could be the result of excessive crankcase pressure. Also, if the pressure leak is coming from the stud passage, you'll get an oil leak, too. Don't bet the farm on this, it's just an educated guess based on very little visual evidence...better than nothing and that's about it, for now.

 

[Chrisqa]

Did it come from the factory like this? Has it ever been apart? Under the four head nuts are flat washers. All of yours are open nuts and you may need to put thread sealer on the lower one towards the kick start side. There are four flat washers under the head nuts one is a brass washer and the others are steel. The brass washer goes on the bottom kick start side where the oil pressure is. It's a sealing washer and it looks like that's where your leak is. On one of my overhauls I lost the brass washer so I put a little Indian Head gasket shellac on a steel washer from my parts bin and put it where the brass washer supposed to be. I was upset because I am meticulous but it sealed up ok. I learned all of my Honda knowledge from a man on YouTube named mini motor man he is a virtual shop manual for Honda. He overhauled hundreds of these little engines. He makes it look so easy to do a complete teardown split the cases and the hard part.... Putting it back together and still be a good engine. He would make a good instructor. I took auto mechanics but never tackled a motorcycle but he was very helpful.