August 5, 2010

Got a chance to work on my Zuma today.

I put im a new contra spring. a blue polini spring. I have two alternative choices, a white spring was 3.74 mm x6 turns and the blue was 3.84x6 turns. I miked the stock spring. It was 3.99 x 4 turns.
The ID of the springs are 44.5 mm and the free length is 68mm for stock and 110mm for the aftermarket springs. I didn't measure the compressed length but would estimate it at 55 mm.

I am not versed on spring constants. I think it would be safe to say that the stock spring has more force but less preload.

I put in the blue spring as it was thicker than the white.

The bike runs better, I am still running the 4gram x6 weights and the bike picks up faster at low end and doesnt flatten out at 30+ mph (before pulling to 50) like it did before. I would say that at low rpm it had more force keeping the rpm higher. I didn't get nearly as much rpm drop off at higher rpm at around 30 mph.

It is irritating to see the speedometer go to the peg and hear the rpm continue to grow.

My compression is pretty low as my cylinder was raised and the head was not machined equally yet. My squish is entirely too fat.