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Author Topic: RE: Are CB750 cranks interchangeable?  (Read 594 times)

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Offline chewbacca5000

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RE: Are CB750 cranks interchangeable?
« on: June 08, 2016, 10:21:26 AM »
Are CB750 cranks interchangeable?  Reason I ask is I want to take a nicer cleaner crank from one motor and put it into another.

I know the case has markings for the bearing shells, but I don't see anything stamped on the crank.
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Offline chewbacca5000

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Re: RE: Are CB750 cranks interchangeable?
« Reply #1 on: June 08, 2016, 10:39:52 AM »
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Offline PeWe

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Re: RE: Are CB750 cranks interchangeable?
« Reply #2 on: June 08, 2016, 10:49:48 AM »
One guideline I heard back in the days as well as earlier this year: Go with green shells as a general rule.
I changed crank that I gave new shells to. I measured with plasti gauge and found my almost new green to be a lttle bit over the limit. Brown made the clearance a little bit tighter.
I could have used green as the experienced racing guys recommended. Service limit is tripple the max clearance.

I think that my well used cases have become wider when the crank journals were really wide. I read a post were Hondaman wrote about widened case by use.
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CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: RE: Are CB750 cranks interchangeable?
« Reply #3 on: June 08, 2016, 04:05:06 PM »
Not likely you will see any 'stampings'. Just scrawled on there. Match the crank etchings with the case stampings as a start. Plastigauge to be sure. This means you could be placing a second bearing order.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)
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