The Hodaka Club Forum

I'm doing a post mortem on a 90 motor and found that the primary gear is missing half a tooth. It appears that the end of one of the clutch screws fell off at the wire hole and lodged in the primary. It is a keyed rather than splined type which seems to be unavailable. It continued to work, but something would always bother me if I put it back together knowing that it needed a crown.

So it would seem that I'd have to either find a used keyed gear or buy both the mainshaft and gear new. The other possibility is to use a 5 speed gear set which I have one of. Is the 5 speed a straightforward swap or a no go? I have the shifter as well but the case is pretty ugly; would the 5 speed shifter mechanism go into the 4 speed LH case?

I'm expecting to say 'I didn't think so', but thought I should ask.

Yes a five speed can be installed but requires a little machining. Clarence (someone on here might have a gear)

I will check my stash.

I have the information; contact me, I’m happy to share.
No
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The question I forgot to ask was whether the change from a key to a spline was because the key was prone to failure or just a move in anticipation of more power, or perhaps a production advantage. I'm not planning to get more than the original 8 hp out of it, so if they were fine stock I'm not going to worry.

I think they were fine stock. The involute spline was probably much tighter and early hodaka's were being raced back then. The change was made December 27 1965, changed at engine number 6559. The keyed shaft was part number 904501 and the involute shaft 904501B, the keyed primary gear number was 904502 and the new gear 904502B. What is your engine number. The MK11 was produced august 19, 1964 with 18 major changes including the frame the workshop manual was not available yet . the next big change was January 21, 1966 with 33 changes, just trivia. Clarence