Brmorgan
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- Apr 22, 2008
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Been thinking about doing this for a while, just had to get up the courage to finally do it. Here it is, $90 pawnshop find last year:
Needed a new fuel line & fired right up. The handle's second mount bar (behind the clutch cover) was broken so I spliced it with a piece of steel bar for now. I have a line on a new one.
Here's the exhaust port before:
And after:
I know it isn't a huge difference, but being my first attempt at this I didn't want to overdo it - I can always remove more later. I widened it by almost 3/16" per side and raised it maybe .020 at most, since I got rid of the head gasket.
I didn't do much to the transfers, just cleaned up the casting irregularities and smoothed out the transition towards the intake port:
The transition at that edge of the transfer ports were ~60° to the wall of the cylinder instead of being nice and smooth. The marks on the cylinder wall are from an extremely soft stone, and can't even be felt by hand but look awful in a photo. I didn't want to go too far towards the intake port though, because the ring ends travel in that area on one side.
Same goes for the piston, just cleaned up the casting in the window:
Once again the flash photography makes it look a lot rougher than it is, though it's MUCH better than before. There were prominent casting lines ~1mm high on the sides of the pin bosses and the whole area was rough in general. I didn't modify the piston at all other than that though.
Needed a new fuel line & fired right up. The handle's second mount bar (behind the clutch cover) was broken so I spliced it with a piece of steel bar for now. I have a line on a new one.
Here's the exhaust port before:
And after:
I know it isn't a huge difference, but being my first attempt at this I didn't want to overdo it - I can always remove more later. I widened it by almost 3/16" per side and raised it maybe .020 at most, since I got rid of the head gasket.
I didn't do much to the transfers, just cleaned up the casting irregularities and smoothed out the transition towards the intake port:
The transition at that edge of the transfer ports were ~60° to the wall of the cylinder instead of being nice and smooth. The marks on the cylinder wall are from an extremely soft stone, and can't even be felt by hand but look awful in a photo. I didn't want to go too far towards the intake port though, because the ring ends travel in that area on one side.
Same goes for the piston, just cleaned up the casting in the window:
Once again the flash photography makes it look a lot rougher than it is, though it's MUCH better than before. There were prominent casting lines ~1mm high on the sides of the pin bosses and the whole area was rough in general. I didn't modify the piston at all other than that though.
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