Author Topic: Mainshaft bearing rings  (Read 705 times)

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Offline Johnny340

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Mainshaft bearing rings
« on: September 29, 2017, 10:45:53 AM »
On the main transmission shaft, I replaced the bearings.  The new bearing came with a full ring and the thin groove does not fit the thicker Honda half ring.  I have read about getting this groove on the new bearings machined wider to accept the Honda half ring but wondered if anyone has simply cut the new thinner ring the right size (half) and used it with the new bearings instead.  Part number 1 in schematic diagram.
1975 CB750F0 Super Sport
1972 CB750K2
1981 CB650
1974 T-500
2003 GSXR750
2006 YZ250

Offline Johnny340

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Re: Mainshaft bearing rings
« Reply #1 on: October 05, 2017, 08:14:29 PM »
For anybody finding this thread and wondering what I did, I ended up buying new bearings (again) but the right ones with the old school large groove in them, found here:
http://www.yamiya750.com/index.php?main_page=index&cPath=246_21_250_52

These guys are great! Hard to find parts at great prices and shipped quickly.  I had them at my door (in Canada) five days later with no additional duty or taxes!
1975 CB750F0 Super Sport
1972 CB750K2
1981 CB650
1974 T-500
2003 GSXR750
2006 YZ250

Offline PeWe

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  • Bike almost back to the 70's 2015
Re: Mainshaft bearing rings
« Reply #2 on: October 06, 2017, 10:52:02 PM »
I ordered all ball bearings just for sure. The bearings with the groove can be hard to find and Yamiya is not expensive either. The 2 needle bearings inside the primary hub is a std bearing that can be found on  eBay for not much.
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