I want to put this cushman m8 I have into a little bobber or cyclekart im building. Stock, Ive heard they put out about 8 hp. Its a ironblock with appears to be a very study set up, not too sure what the crank and piston rod are made of, has a cam driven sump oil pump for long hauls and has no evidence of a governor. What can I do to build it up to be a little power house, a guy on the hamb said its possible to get 20hp out of one, I dont know how true this is but I want to see if I can at least get a little gain.
dennis carpenter web site is a good place for engine parts and also will sell you a aftermarket carb set up. also do a search on old husky engine build up's.
goodluck....:thumbsup:
Dennis Carpenter Ford Car, F-100 Pickup Truck, Tractor and Cushman Scooter Restoration Parts
http://www.oldminibikes.com/forum/general-minibike-talk/26707-my-pick-find-2010-a.html
goodluck....:thumbsup:
Dennis Carpenter Ford Car, F-100 Pickup Truck, Tractor and Cushman Scooter Restoration Parts
http://www.oldminibikes.com/forum/general-minibike-talk/26707-my-pick-find-2010-a.html
They used these motors in 1/4 midget racing 'back in the day' and those guys got 20 hp and more out of them. But they converted them to water cooling and ran total-loss ignitions with lightweight flywheels. Hardly practical.
I think 12-15 hp is pretty achievable though.
Focus on the intake flow and the compression ratio. You might be able to overbore to 3.00 inches, but the gains there aren't much and you've got a pretty good chance of breaking the cylinder wall.
Strip the block and look at the intake & exhaust ports. Then make the intake port look like the exhaust port. You'll have to fill it with epoxy or brass, then reshape it with a gradual radius. One of Carpenter's oversize intake valves will help, too. A 24mm Amal or Mikuni carburetor will easily give you 15hp. "Relieving" the cylinder isn't necessary at the 15 hp level.
Get one of Carpenter's Super Stock cams.
You may have to remove some material from the head to clear the larger intake valve. Keep it to a minimum to keep your compression ratio as high as possible. Carpenter's billet head is a sexy little number, but not absolutely necessary. Use the thinest head gasket you can afford.
Check this out:
Bob's Motor Page one
I think 12-15 hp is pretty achievable though.
Focus on the intake flow and the compression ratio. You might be able to overbore to 3.00 inches, but the gains there aren't much and you've got a pretty good chance of breaking the cylinder wall.
Strip the block and look at the intake & exhaust ports. Then make the intake port look like the exhaust port. You'll have to fill it with epoxy or brass, then reshape it with a gradual radius. One of Carpenter's oversize intake valves will help, too. A 24mm Amal or Mikuni carburetor will easily give you 15hp. "Relieving" the cylinder isn't necessary at the 15 hp level.
Get one of Carpenter's Super Stock cams.
You may have to remove some material from the head to clear the larger intake valve. Keep it to a minimum to keep your compression ratio as high as possible. Carpenter's billet head is a sexy little number, but not absolutely necessary. Use the thinest head gasket you can afford.
Check this out:
Bob's Motor Page one
