Posted on Sunday, March 23, 2003 - 01:14 am:

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Peter said: If that is a 'D' grind (it will be stamped on the lobe with a number), then it will also have a colour on it. If you are able to buy the single cam, try to get the same colour. If you can't, then go smaller in gear size colour, not bigger.
(big) black, yellow, green, white, red, blue, brown (small)

If it has '15' stamped on the lobe with another number, then you have X1 cams which are what we get in M2's in Europe. They don't have different sizes so you don't need to worry about sizing. They're just noisy.

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Aaron said: Hey Bill ... this is a 2000 model M2?

Hate to be the bearer of bad news, but looking at my '00-'01 parts book, they don't list separate cams. You have to buy a whole set of 25193-00A.

That part number is the "high contact ratio" set, meaning that it's got a different tooth pitch from '99 and earlier cams. They don't have to be fitted to each individual motor the way the old ones did, it's one size fits all.

By comparison, in a '99 and older bike you could buy individual "D" cams and each cam gear was available in 7 different sizes, except the #2 cam which was available in 49 different sizes since it has 2 gears. Also there were 7 different sizes of pinion gears, the new HCR cams again have only one size pinion gear. The number of different possible combinations in a '99 or older motor is mind boggling.

Now, you really want to get confused? I'm not at all sure your motor is fully high contact ratio now. I believe 2000 was a transition year, and only the pinion to #2 connection is HCR, and they didn't go HCR across the board until '01. My guess is that your pinion connection has a noticeably finer tooth pitch than the other connections, no?

The *easy* thing to do is to just buy a new set of cams, but it may be possible to change just one, if this hunch is correct.

Which cam is it that shows the wear?

If it's #1, 3, or 4, and it's not HCR, you *may* be able to buy the individual cam. Give me the color code and I'll look up the number and we'll find out if it's been discontinued. Sometimes they discontinue out-of-production parts if they have an alternate service solution, which they do in this case, they can make people buy a whole set of HCR cams.

If it's #2, that bastard 2000 cam with an HCR drive gear and a coarse tooth gear for connecting to the adjacent cams is not available individually. However, notice how the HCR drive gear is just pressed on there. It's not difficult to remove that gear and move it to a new #2 cam, I've done it many times, I'll even do it for you if you send me the stuff. Again, let me know the color code on the current #2 cam and I'll look up the number.

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And Aaron later said (God bless him!): 25666-91 - cam gear, front exhaust, black

A little birdie told me about that awhile back. I've had 2 other 2000 model motors open and they both were that way, HCR on the pinion connection and the old style gear cut between the cams. So I had reason to believe yours was probably that way, too, it was more than just a hunch.

The XB has high contact ratio just like the 01-02's, so there's no fitting. Yours is the last year of that cam fitting stuff.

I've been told that the old style cam gear teeth is a stronger setup, I have no idea if that's true or not though. I haven't seen widespread failures of the HCR's so I'm skeptical. Obviously each tooth is stronger in the old design but you've got more teeth engaging with the HCR, right? Blake could probably do the math for us

Be forewarned, that part number I gave you is out of the '99 parts book. But if my understanding of what-they-changed-when is correct, and I believe it is, it'll go right into your motor. Just be aware that if you ever have to replace your #2 cam with a '99 model, you'll have to move that drive gear from your old cam to the new one. But it ain't hard to do.

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