batrider
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- Joined
- Aug 9, 2008
- Messages
- 2,360
I purchased a 1" dial indicator and magnetic base from Harbor Freight on sale and was playing with it this morning. The numbers agree pretty closely with other better quality measuring devices I have (a couple old Starrett micrometers that my grandfather had and good digital vernier calipers) so it isn't really all that terrible, just cheap.
Anyway, I decided to measure cam lift. The head is off right now. For a Combat the manual says .346" exhaust and .390" intake. I'm getting .344" and .386" on the left side and .339" and .388" on the right. I took the lowest reading and made that my zero and then took the highest reading as the lift. I measured each lobe several times and repeatability was good.
Now I'm wondering how close the cams were to the written specs when new. If the cam was originally case hardened then it makes me worry a little about the .339" lobe. The bike has about 35K miles on her and the cam is original. Cam lobes looked OK and similar to each other just by eyeball. How much variation should I expect?
Anyway, I decided to measure cam lift. The head is off right now. For a Combat the manual says .346" exhaust and .390" intake. I'm getting .344" and .386" on the left side and .339" and .388" on the right. I took the lowest reading and made that my zero and then took the highest reading as the lift. I measured each lobe several times and repeatability was good.
Now I'm wondering how close the cams were to the written specs when new. If the cam was originally case hardened then it makes me worry a little about the .339" lobe. The bike has about 35K miles on her and the cam is original. Cam lobes looked OK and similar to each other just by eyeball. How much variation should I expect?