08-17-2007, 11:44 PM
got the rods back from the machine shop today. put together the jig to balance them, only to find that the small ends were off by .1 grams, and the big ends were off by .3 grams. total weight the rods are .2 grams apart. Basically, I lucked out, this is the most closely matched set that my extremely experienced (35+ years) coworker and partial mentor has ever seen.
Aside from that, this project is getting bigger and bigger. I found out that we have a few 336 cams in stock, so I put one on hold. The 336 cam is a performance cam made by BMW. They started making them in the early seventies, because sidecar racers wanted a cam to raise the powerband without going with a super-radical custom camshaft. The opening and closing ramps are the same as a stock cam, but it has more lift and duration. Another coworker has a pair of 40mm bing carbs that I'm buying off him for cheap, to replace the stock 32mm carbs. This means I'm on the lookout for a pair of cylinder heads from an R100S, R100RT, or R100RS from 77-84, which have intake stubs for 40mm carbs and larger valves.
I'm going to stick with the stock 800cc displacement though, going to reuse the stock pistons (lightened and balanced, of course).
All of this means that the bike will take longer to complete, but man alive will it be a runner. I'll upload pics next week of the assembled/cleaned bottom end, possibly even installed in the chassis.
Aside from that, this project is getting bigger and bigger. I found out that we have a few 336 cams in stock, so I put one on hold. The 336 cam is a performance cam made by BMW. They started making them in the early seventies, because sidecar racers wanted a cam to raise the powerband without going with a super-radical custom camshaft. The opening and closing ramps are the same as a stock cam, but it has more lift and duration. Another coworker has a pair of 40mm bing carbs that I'm buying off him for cheap, to replace the stock 32mm carbs. This means I'm on the lookout for a pair of cylinder heads from an R100S, R100RT, or R100RS from 77-84, which have intake stubs for 40mm carbs and larger valves.
I'm going to stick with the stock 800cc displacement though, going to reuse the stock pistons (lightened and balanced, of course).
All of this means that the bike will take longer to complete, but man alive will it be a runner. I'll upload pics next week of the assembled/cleaned bottom end, possibly even installed in the chassis.
horizontally opposed>*