cb400f

[pubboss1]

Hi all, newbie to the club here but not new to m/cycling. I am rebuilding a 1975 cb400f. Having started to position the crank on the upside down case mains and the primary and countershaft gear shafts into position, I have found unacceptable (rocking) movement on the countershaft low gear. Part no.23420-377-000 runs on a bi-metal bush that is 23mm o.d. by 20 mm i.d.  Now unavailable separately,(bush only)  we are going to have a bronze or phosphor-bronze bush made. It is uneconomic to have one made so would anyone like one earmarked for them. We are looking at having up to 10 made in one batch and putting them out there for maybe a fiver plus postage for each one. No profit in it, but that's not the point. Hope it would help other owners/rebuilders. Please reply through this forum.Thank you. Neil

[exvalvesetdabbler]

I ran into that issue 20 years ago.  If I remember right the bush has dimples on the inside to retain a bit of oil.  At the time I approached a couple of engineering firms to have the gear re bushed.  Their best option was to cut a fine groove on the inside to aid ingress of lubrication.   I wasn't sold on the idea so managed to find a new one at a reasonable price.

Be interested to see what any engineers on here might have to say.

Regards
Dave
   

[Laverda Dave]

I had the same issue recently with Ratty. Ted came to the rescue with a good set of previously enjoyed gear shafts.
Knowing now how hard these are to source now I'll take one please to keep in my spares stash for the future 👍.
Let me know the payment details etc once you know the price and availability 👍.
Cheers
Dave

[pubboss1]

Hi again. As for the oil retention within the microns space between the shaft and the bush, we propose having up to 20 small indents put into the inner surface with a dremmel and small grinding ball, maybe 2mm diamater . It will need a minute touch for each spot and would only take 5 mins. or we could have a counter-clockwise groove put inside for lubrication. Either way we would be happy for further comments. Thanks.

[XS850]

Hi, I also had this problem and found an exact fit with a phosphor bronze bush aftermarket (see photo) - reasonable price I thought (SKF PRM202315 Metric Plain Wrapped Bronze Bush 20x23x15mm; £5.33, Shipping: £1.99, VAT @ 20%:£1.47, Total: £8.79) from Simply Bearings.
Don’t know if it helps!

Cheers - Bruce

[pubboss1]

Many thanks for this latest info. Have found these and ordered last night, seems a perfect fit, great help.