Author Topic: '78 CB750k Engine Bearings  (Read 380 times)

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Offline Gonzo750

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'78 CB750k Engine Bearings
« on: May 04, 2019, 06:41:34 PM »
Hey all,

Does anyone know what type (color) bearings a 1978 CB750k takes for the crank and rods? Or does it depend on the individual engine and I have to open it up first to figure it out? The reason I ask is because I don't want to tear it open only to wait for the parts to come; I want to have them ready to go and do it all at once.

Thanks,

Diego
1978 CB750k - Barn Find

Offline rotortiller

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Re: '78 CB750k Engine Bearings
« Reply #1 on: May 04, 2019, 07:38:16 PM »
have to open it up first to figure it out

Offline jamesw

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Re: '78 CB750k Engine Bearings
« Reply #2 on: May 04, 2019, 07:39:51 PM »
You'll have to take the engine apart.

To get a preliminary gauge, you can use the letters stamped on the case & scored on the crankshaft & rods, and then use plastigauge to get a more accurate measure to determine how tight or loose they are.
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Offline PeWe

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Re: '78 CB750k Engine Bearings
« Reply #3 on: May 04, 2019, 09:33:26 PM »
Or use green shells for crank which work fine in most engines. A method I have heard since early 80's.
Case has stamped letters like B BBBB, crank has very vague marks difficult to see on its side where the chains are fitted that describe thickness of crank journals and for rods.
Easier to measure with a micrometer. CB750 shop manual has all details.
RTFM...  ;)
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