120R cam change

[Hilly13]

Thanks Robin, it is a bit above my pay grade but I understand what you say there, I would love to see the 57 and 37 mapped out, I ran both of those in the same bike with no other changes except to tune it, 97" 4" stroke, the 37 was better, I don't know why, the 57 just felt off in the higher rev range where the 37's sung.

[Hillside Motorcycle]

Here we go checked with the owner and the piston kit is a TMan 124 kit with 4.5 cc pop ups.So that makes it 11.25.I like the 662-2PS2 but am concerned about detination as this is a carbureted machine

On a carbed bike, we like to hold the ccp in the sub-200 zone.
195 is our threshold.

[Timinator]

There are several cam measuring machines out there, the old Cam Dr, for one. Those can usually be had used for a Grand or so. They  measure to a ten thousandth of an inch and a tenth of a degree. That's plenty  for anyone not engaged in the business of cam grinding, and even some I know of that are.
A degree wheel, lathe, pointer, and 1" travel dial indicator is all that's necessary to measure lift, duration at advertised, duration at .053, and at .200, and lobe centerline. If you are careful you can get very good results of the cams ramp rate too. The shorter the degree difference between advertised, .053, and .200 gives you the ramp rate. Those are the most important, non changeable characteristics (to the end user) of a cam. With an offset sprocket you can change the advance or retard of the cam. There are several good cams out there that are made better by retarding them 4  degrees.
We won't buy any cam from anyone that doesn't supply those specs, as many are simply reboxed versions of an off the  shelf cam with a lot of added hype. I learned that 30 years ago when I bought my first cam analyzer...  TIMINATOR

[Sunny Jim]

At 10.8:1 I used Tman 660sm. All day arse kicker in a 120r with good manners.
The old Crane HTC 296-2 wOrked well also.