 Re: Sprocket/chain drive help
this is how i made some of my first 1/2 inch bike size drive sprockets to fit the tranny i used to motorize my bikes . if you need a drive sprocket to fit the shaft of the chain saw motor you need whatever is attached to it now . remove it . and use that for start . go to the bike shop and tell them you want an 11 t 1/2 bmx cog . its a steel very small chainring they have them in 11t 12t 13t get the 11t . get a hole saw that fits inside the llt cog perfectly . the hardest part will be centering it . you can use a grinder also . draw the circle on it first so you will have something to guide you . now you have to weld the 11t onto your blank that you just made . this is not an easy project you are undertaking . but if you can make this drive gear , you can do the rest . also , you might rethink the chainsaw motor . that has a ton or torque and with no tranny could rip your bike apart . some better motors you could find around the house or shop . are rototiller motors two strokes , blower motors , check Craig's list for a broken scooter , with a fifty dollar scooter . if the motor runs , that's a great start to a motorized mountain bike . with that scooter you will get your gas tank, motor , throttle trigger , throtle cable , kill switch , and a 5 to 1 tranny . lots of time people sell there scooter because the frame is broke , but ll the stuff you need is still there . the zooma scooters and others use the gas tank mounts under the motor to mount the engine to the frame and these are prone to breaking because they were not designed to be mounted in that way . and they break from the torque of the motor . that is great for you . good working motor but no good for a scooter anymore . but it will mount to a bike . and please while working with metal and hand tools PUT ON SOME GOOD EYE PROTECTION .have fun  | 
