CB72 Engine serial #'s

rrietman · Post by **rrietman** » Mon Aug 02, 2010 12:30 am

So I'm sifting thru some engines, looking for a good one to rebuild for my 62 CB72. I find one with engine # CB72E- 930 not 5 digits, not 6, just three digits. the crosshatching in the # area is intact and looks very original. I have piles of these engines, 305's & some 250's but have never seen a 3 digit serial # ? anybody else? I did find a 62 250 engine here but the crank bearings have been pounding the case so I'm thinking I'll go with this #930 case as it looks very good.
Thanks
Randy

teazer · Post by **teazer** » Mon Aug 02, 2010 9:43 am

I have a set of 61 cases -112157 with breather tower and 62 - 212477.

Maybe your -930 is a 59 or 60 set. Are they identical in every detail to any other cases you have there?

rrietman · Post by **rrietman** » Mon Aug 02, 2010 9:18 pm

This case is post breather tower, looks identical to some other62-64 cases. has a 6 plate clutch with not two but three wire retainers in place. I'm not the first one in this engine so I'm not assuming anything about original parts. but the serial # is weird.
Randy

jensen · Post by **jensen** » Tue Aug 03, 2010 2:08 am

Hi,

Nice found, and seems to could be a 59 engine, the number starts with a 9.
Is the cylinder head (top) cover original to the engine ? Does it have the holes for the condenser ? (it should be attached like a dream, on the cylinder head cover).

Does it future a 360 degree crank ?, or a 180 degree crank ?

Jensen

rrietman · Post by **rrietman** » Tue Aug 03, 2010 6:51 pm

180 crank, no condenser mount holes, it has a primary chain tensioner. anybody know if new, un numbered replacement cases were available in the day? I only ask because the vintage aircooled cars I also work on DID have such a thing.
Thanks
Randy

teazer · Post by **teazer** » Tue Aug 03, 2010 7:20 pm

yes, replacement cases were available. AFAIK originally they were die cast, the same as production items and later on they were sand cast and much thicker and stronger.

Yamaha supplied crank cases with no numbers in that crucial number pad area. Honda cast cases were also blank but I can't speak for the die cast cases. Probably teh same.