Rocky_Motor
New Member
This thread really is just me thinking out loud, but if you'd like to take a read, please do!
While I haven't even built my first 2 stroke motor yet (waiting for the kit to arrive ) I am already planning my build for my favorite engine of all, the 125cc Lifan. It has to be IN-FRAME. Otherwise balance will be off and harder to maneuver going up the mountain. Or down for that matter. Especially because the motor is a wopping 50 pounds!
So these mountain bikes usually have a 30, 60, 90 degree V frame. This means I can apply a little calculus (late pre-calc I suppose) to figure out what size frame I need to get the motor to fit. Sin, cos, tan, what have you.
Edit: Drawing it out I realized that I can just measure it.. But! if you wanted to figure it out exactly you could do it the mathematical way...
Here's how this works:
A classic relatively cheap mountain bike. Front suspension is important. Notice the frame is the triangle I am referring to. If I calculate it or measure it, I need to measure 17" from the seat tube+top tube". On my current bike that leaves 3 inches from the end.
If that question mark can be 9" (might be 11") Then the motor will fit. It's a stretch but a bike with a long top tube could do it. There's also a frame that the bottom tube does not attach to the top tube, but rather leaves a piece of tubing between the two about a half foot depending on the size. This could be even better
Once the motor is fitted and situated, it's only a matter of building the chain part of the bike. For this extra power I can't use the standard spoke grip sprocket. Buying the heavy duty sprocket adapter from ?: SPORTSMAN FLYER MOTORBIKES :? will be perfect. This may change however, as it would be ideal to have some kind of shift kit OR derailer to have a 2-3 speed bike mounted to a former disc brake hub.
Now that the motor is fitted, the chain driving is solid, we need a clutch. Turns out the sexy machine has it all built in with 4 up speeds. Fantastic, problem solved.
Ok.. At this point I should be able to run the motor (adding the parts like kill switch, throttle, ect.. Those aren't the hard parts though. But why stop there?
Let's buy a pit bike body kit!
The cheaper clone version will do, all we really want is the body shape. At this point I think it is impossible to design unless you have it there with you so that you can see how things will fit and what looks good. This does not serve for purely cosmetics though. The sidings will be perfect to make the bike safer. We can put them on the side to prevent any accidental burns on your legs from an accident or just every day riding.
To go even further, we can carbon fiber wrap it! That'll make the parts look much better than a flat black.
At this point I think we generally have the bike ready to rock. This upcoming summer, I'll make this dream come true!
While I haven't even built my first 2 stroke motor yet (waiting for the kit to arrive ) I am already planning my build for my favorite engine of all, the 125cc Lifan. It has to be IN-FRAME. Otherwise balance will be off and harder to maneuver going up the mountain. Or down for that matter. Especially because the motor is a wopping 50 pounds!
So these mountain bikes usually have a 30, 60, 90 degree V frame. This means I can apply a little calculus (late pre-calc I suppose) to figure out what size frame I need to get the motor to fit. Sin, cos, tan, what have you.
Edit: Drawing it out I realized that I can just measure it.. But! if you wanted to figure it out exactly you could do it the mathematical way...
Here's how this works:
A classic relatively cheap mountain bike. Front suspension is important. Notice the frame is the triangle I am referring to. If I calculate it or measure it, I need to measure 17" from the seat tube+top tube". On my current bike that leaves 3 inches from the end.
If that question mark can be 9" (might be 11") Then the motor will fit. It's a stretch but a bike with a long top tube could do it. There's also a frame that the bottom tube does not attach to the top tube, but rather leaves a piece of tubing between the two about a half foot depending on the size. This could be even better
Once the motor is fitted and situated, it's only a matter of building the chain part of the bike. For this extra power I can't use the standard spoke grip sprocket. Buying the heavy duty sprocket adapter from ?: SPORTSMAN FLYER MOTORBIKES :? will be perfect. This may change however, as it would be ideal to have some kind of shift kit OR derailer to have a 2-3 speed bike mounted to a former disc brake hub.
Now that the motor is fitted, the chain driving is solid, we need a clutch. Turns out the sexy machine has it all built in with 4 up speeds. Fantastic, problem solved.
Ok.. At this point I should be able to run the motor (adding the parts like kill switch, throttle, ect.. Those aren't the hard parts though. But why stop there?
Let's buy a pit bike body kit!
The cheaper clone version will do, all we really want is the body shape. At this point I think it is impossible to design unless you have it there with you so that you can see how things will fit and what looks good. This does not serve for purely cosmetics though. The sidings will be perfect to make the bike safer. We can put them on the side to prevent any accidental burns on your legs from an accident or just every day riding.
To go even further, we can carbon fiber wrap it! That'll make the parts look much better than a flat black.
At this point I think we generally have the bike ready to rock. This upcoming summer, I'll make this dream come true!
