1973 harley Davidson 90x NEED HELP!!!!

#1
I just bought a 1973 Harley Davidson 90x mini bike i got the bike to run and it will switch gears up to second but when i switch it to third it bogs its self out does any one have an idea what it might be
 
#4
Common problems with an X-90 if the carb is jetted correctly:

Weak spark - clean or replace points
Dirty Carburetor - clean
Incorrect oil - use a good quality 2-stroke oil
Oil pump is out of adjustment - readjust to factory specs.
Low compression - replace rings
Plugged exhaust - submerse in heavy duty cleaning agent and inspect closely to make sure everything has washed out.
 
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