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1965 Honda CP77 — Ulsan Metro City, Rep. Korea
Restored with original parts — Owner: J. Doe
cam bearing clearance
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prodigal son
- honda305.com Member
- Posts: 14
- Joined: Thu Apr 10, 2025 8:26 am
cam bearing clearance
As long as the motors apart, the cam bearing do spin nice. If I was to replace them, what clearance are the original bearings? Are they CN or C3 ? Thanks, Gary
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Tim Allman
- honda305.com Member
- Posts: 526
- Joined: Tue Dec 02, 2014 9:25 am
- Location: Guelph, Ontario, Canada
Re: cam bearing clearance
I've never really thought about this although I normally replace them if they are old or their age is unknown. The parts book just calls for 6004 bearings, which implies CN, so that's what I have used and I have never had a problem.
I found some guidance here:
https://tflbearing.com/blog/understandi ... rance.html
which leaves me thinking that CN should be used unless there is a good reason not to. In particular, the bearings are not press fit and I think the top of the head is unlikely to get much above 100℃, especially near the ends of the shaft which are in the air stream. That said they also make a pretty good case for C3 as they suggest them for motorcycles and electric motors which are unlikely ever to get as warm as a motorcycle.
It seems that you have a choice but I'm not worried about my bike with its CNs.
I found some guidance here:
https://tflbearing.com/blog/understandi ... rance.html
which leaves me thinking that CN should be used unless there is a good reason not to. In particular, the bearings are not press fit and I think the top of the head is unlikely to get much above 100℃, especially near the ends of the shaft which are in the air stream. That said they also make a pretty good case for C3 as they suggest them for motorcycles and electric motors which are unlikely ever to get as warm as a motorcycle.
It seems that you have a choice but I'm not worried about my bike with its CNs.