Re: Brand new to MB's and need some info..
the 42cc runs faster than this old man feels safe with. Frankly I have never had it wide open except going up hill. But then my china kit is the same I don't open it up except going uphill. I don't have a speedometer on it.
My builds are friction drive so they have a little less power than the kit engines. Mostly shows up going up the hills. Some it sails up some it struggles but that is true with the china bike as well.
I would guess the 42cc friction drive is about 80% of the china kit. That is just a guess.
Take a look on ebay at chainsaws. There are some brands that are okay some are over priced for a bike build. Mine is a 42cc craftsman and a 33cc poulan.
On the tensioner I have had three different ones and the only way they ever worked for me was to set the bike up for the motor chain then use the tensioner on the bicycle chain since the pedaling is easier on it than the motor it works fine.
My posts have entertainment value only. A bike ain't yours till it has your blood on it. Then it owns you.