Motorcycle Repair: My Sons 07 PW50, vent hose, yeah buddy

Question
Hello,



I'm new to working on bikes and don't know a whole lot about working on them.  Only what I have read from the Internet.  So hear it goes.



I bought my son an 07 PW50 about 2 months ago.  After one of his riding sessions I washed off the dirt.  When I went to start it up a few days later I could start the bike and let it idle with the choke on.  However as soon as I released the choke the bike would not idle.  So I did my some research and ended up taking apart the carb and using carb cleaner to clean it.  I fixed the idle problem. I took my son down to the park and it seemed to run fine.  Yeah buddy.

Anyway,  we went up to the Mountains last weekend, about 7600FT, and his bike would start fine and it would run for about 10-15 feet then the bike would lose power and would not take him any further.  When he released the throttle he was able to get power again for another 10 feet when he applied the throttle again.  Any idea of what is causing this?

Answer
It sounds like it is not getting enough fuel.
Does it keep running with the choke on?
Make sure the air filter is clean, the air is thin
in the mountains. Remove the gas cap to see if
any pressure has built up due to a plugged vent
in the cap, also make sure the bottom floatbowl vent hose
on the carb is hanging down freely. If this hose was
accidently plugged a vacuum can starve gas flow.
Check for gas coming from the tank and lastly
recheck the middle main jet in the carb for obstructions.
It sounds like a fuel problem, but it might not
hurt to replace the spark plug also.
Since it is relatively new, I would not suspect
a plugged exhaust system.

Hope this helps :)