Ok , I was just out messing with the D B , The motor that came with it has issues with idle prev owner told me , BUT I just happen to have a barely used 7 1/2 hp briggs motor kickin around , so tried fitting that in,,no issues as I just have drill 2 holes to mount the engine.....have a 17 tooth cent clutch , bike has 70 tooth sprocket , tire is 16 inchs tall...stock rim . o yeah I need to find a new fuel tank as stock briggs to big. another issue I had was briggs muffler was to tall , so I used muffler off old motor but had to ream mounting holes to briggs motor...( I will be looking for header type exhaust as well as after market breather(filter) ...that's it so far today , go back out after BRUINS game , Go Boston