Loss of high RPM spark?

When you have a gasket leaking at the cylinder base you will see an oily ooze coming out of it as the engines crankcase is pulsing form pressure changes as the piston rises and falls. Usually a leak on the base gasket of the cylinder will be clean oil/fuel. If you have a leaking head gasket it will be nasty black oily stains same for the exhaust pipe and if the exhaust leaks it will get noisier as the leak gets worse and black oily crud will get all over. The exhaust leak most of the time will not make it run poorly. You could run it with no pipe but you will soon need hearing aids as it very loud. Your spark plug will leak at times leaving a black oily crud. If you have a crankcase seal leaking it sometimes will be clean oil/fuel or it can also be black oily/fuel oozing out around the crankshaft behind the mag rotor or behind the small gear on the clutch area. Your intake leak will not show up you need to spray something on this area if its leaking when you spray this area it will make the engine change its speed either speed up or slow down and sometimes die.
You might try this on your carb. Try this, take the carb off the bike take off the float chamber turn the carb upside down while its upside down look at the 2 tangs are they level or sticking up a little or sticking down a little? Try to make them both set level by gently bending them so they both are the same. Hold the carb upside down and get both tangs level. If you need to then adjust the carbs float from now on gently bend it where i showed in the carb post. If fuel runs out all the time the float will need to shut off sooner so while holding the carb upside down bend the fulcrum arm so the tangs are say 1/8" higher than when you started. This will lower the fuel level you are going to have to play with this. Bottomline if you can't get it to work let me know I'll PM you my address I'll get the carb to work on my bike and return it to you. Another thing if your engine is new or close to it its going to run kind of crumby until its broken in.
Norman

Pablo I have no idea why I didn't think of this sooner, but you can test any joint for gasket or air leak by simply spraying carb cleaner on the joint while the engine is running at idle. If you spray any joint and the engine speeds up, you have a leak there. You could test them all for a bucks worth of cleaner and be absolutely sure it isnt a leak. Or even a crack in the head that way. Just get it warm put it on idle and shoot the engine one spot at a time to be sure.

Sometimes I think I have alzheimers. I must have done that with a dozen carb gaskets over the years. It will work at any joint even the bottom of the cylinder pot.

Then it can't be an air leak. If you cut off the oxygen, and it doesn't change then that can't be the problem. I'm totally stumped. When you get your new carb send the old one to norman see if he can figure it out.

very cool. You should be able to find it by switching out parts.

awwesome. now that is service. let us know how it runs

Yes that is good service and do let us know

looking forward to hearing you bicycle engine is running like it is supposed to

I'm wondering when your buddy shows up change out the cdi/coil box and see what happens. I'm thinking something is going to **** in your ignition when it gets warm. I still wonder about your carb but it should run if you haven't drilled the main jet or anything like that. If the cdi doesn't help change the carb out. something is screwed up.