XR600R cam

I'm thinking about putting a new cam in the XR. Anyone have any ideas on which one/types are best? Don't want to go too crazy, as I plan on keeping it on 91 octane. Eventually, it'll get punched out to 628, so I'd like to keep it compatible with that. It already is jetted, snorkel removed, FMF pipe, and UNI air filter. Also, has anyone used the header wrap tape and gotten good results?

Hi Nate,

Changing the cam shouldn't make any difference with respect to the

octane rating of the gas you run. That would change if you increased

the compression ratio. Just remember that if you have too much valve

overlap, your engine won't want to idle very well.

Good luck,

Bob East

I worded that wrong. I meant not too crazy with the compression, or engine as a whole, which would necessitate the higher octane. Going with the Hot Cams stage one kit.

Hi Nate,

Yes, that might necessitate the use of higher octane gas if the

compression ratio goes above what it currently is. I don't know

what the upper limit compression ratio is for an air-cooled engine

with respect to using 92 octane gas. I do know that a water

cooled engine can be successfully run at 10.5:1 because that's

what my Porsche 928's stock compression ratio is. It tends to

differ with air-cooled engines because the heads run hotter than

liquid cooled heads. For example, the airplane I used to own had

a compression ratio of 8.7:1 and was considered "High compression."

It wouldn't run on 87 octane gas. It was air cooled. The head

temperature during climb-out, at full power, would be at least 300° F.

Anyway, it sounds like you'll have a real handful once you finish

with the mods.

I, on the other hand, only want my bike for cruising the logging

roads, in the national forests, and a couple of ORV trails where there's

some excellent mule deer hunting. I'm too old for that hardcore



Bob East

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