Sunday, March 22, 2009

Metra 80 Prep

The other day I picked up the Metra80 large port that had been chilling in the display case at Seattle Mopeds. It was a bit dusty, and it had been sitting there for quite a while. I decided to go Metra80 for the magnum for a few reasons.
  • Magnums need big cylinders, no little maxi cylinders
  • Metra80 has a beautiful matching head
  • Metra80 works well with my existing intake for the Parma kit
  • Metra80 will make good power, but not so much power I destroy my 2 speed every few months
So as I look at the dykes ring that rides right atop the edge of the piston, it looks rather large to me. Decided I should measure the ring end gap. To do that, place your ring in the cylinder, and then press it down half way between the top of the cylinder and the exhaust port, using the base of your piston so that it is level. Unfortunately, the metra80 skirt is already trimmed and not level, so I had to get out my caliper and measure down to ensure it was level. With the ring level, insert a feeler gauge into the gap until it fits just inside without binding. My gap was .002 in (.051mm) which I am quite certain is waaaaaaay to small. So perhaps I got a wild ring or something, but I feel if I put it together as is I'm going to snag a ring quite quickly. Once the heat builds up, that ring expands and the ends will push into each other causing all kinds of binding and calamity. So I'm going to do a little research and widen my gap, and I will of course, keep you posted.

1 comment:

Anonymous said...

are you going to la? metra 80 za50 sounds scary but awesome!