I have what I think is a decent used MC21 crank except for the fact that it is missing the center o-ring (part # 91301-KV3-771)! Assuming I can get this part (a big assumption) or a matching substitute (a smaller, but still significant assumption), does anyone know if the O-ring can be installed without taking the crank apart, i.e., is it possible to stretch the O-ring enough to fit it on in the middle without breaking it or otherwise weakening it? Thanks for any help.
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-Jim
'93 MC21

yes you can fit a new o-ring without taking the crank apart but order a few of them

Yes this o-ring is available.

Be extra careful when fitting it though as they do snap quite easily if you're a bit rough with them. Yes, I've snapped one before

What I do is to gengtly roll the o-ring in my hands for a minute or so to warm up the rubber and then carefully work it over the crankwheels and conrod trying to use the minimun amount of stretch.

thanks guys - I was beginning to think I was going to have another very expensive doorstop - running out of doors! Thanks.
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-Jim
'93 MC21