Mammoth
Member
I like looking at all the pics on this forum so I figured I would add some from my collection.
This 5 horse Tecumseh engine came with the Invader when I first bought it. I messed with it a little bit to get some more hp but it still wasn't enough.
Purchased the 420cc and got to work. Noram clutch
Took off the governor so defiantly had to add an aluminum flywheel. Timed it at 30*
Ground 2 angles on the valves. 45* for the seating surface and then 30* to help the gas move past.
Chucked the exhaust valve in the drill press and sanded the 90* corner off the head. This allows the gas to pass by more efficiently. We always gain 2 to 3 percent when this one move is done. Right here.
Welded up the squish band and then milled down the head to get 13-1 compression.
Ported it. Pics don't do it justice. Should have taken them before the valves were installed.
Ordered one of the headers off the web. Did the math to figure out how long the header needed to be on a 420cc engine that is going to run around 6500 rpm and came up with 33 inches. The header was far short of that so I added some length. Its at 36 inches now. Once I get a tachometer on it I will trim it to proper length.
Made an intake tube for a 40mm Dellorto and installed it with the biggest air filter I could find.
This 5 horse Tecumseh engine came with the Invader when I first bought it. I messed with it a little bit to get some more hp but it still wasn't enough.
Purchased the 420cc and got to work. Noram clutch
Took off the governor so defiantly had to add an aluminum flywheel. Timed it at 30*
Ground 2 angles on the valves. 45* for the seating surface and then 30* to help the gas move past.
Chucked the exhaust valve in the drill press and sanded the 90* corner off the head. This allows the gas to pass by more efficiently. We always gain 2 to 3 percent when this one move is done. Right here.
Welded up the squish band and then milled down the head to get 13-1 compression.
Ported it. Pics don't do it justice. Should have taken them before the valves were installed.
Ordered one of the headers off the web. Did the math to figure out how long the header needed to be on a 420cc engine that is going to run around 6500 rpm and came up with 33 inches. The header was far short of that so I added some length. Its at 36 inches now. Once I get a tachometer on it I will trim it to proper length.
Made an intake tube for a 40mm Dellorto and installed it with the biggest air filter I could find.