Pullstart/roto back plate's are 1 BIG air leak....I would suggest getting a starter box and ditching the pullstart set-up in favor of a sealed back plate...not only will the motor run better but will tune easier and overall make a little more power due to the 1 way not being in there.
the exhaust pipe Wont burn through the line but having your fuel tube resting on the pipe heating the fuel isn't a smart idea.
