CB350/4 Countershaft bearing.

[Gixxer-18]

Just Curious, is the countershaft bearing replaceable on a 350/4.?  There's nothing wrong with my bearing, and I'm going to reuse it.
 but I can't see how the bearing locating ring can be removed? Has anyone done it?
Is the oil seal surface ring an interference fit on the countershaft? If that's removed it then looks like the bearing and then the gear could be taken off the shaft?
How would you do it? , bearing in mind that a NOS shaft, gear, and bearing assembly is on sale for €229.00! And only four left!
Nigel.

[mike the bike]

Which one is the countershaft, the clutch side or the output side?

[Gixxer-18]

It's the output side, the bearing nearest the final chain sprocket.

[AshimotoK0]

Think it's pressed on like the CB250/350K. On that bike initially,  the bearing and shaft were available separately but laterally only as a complete assembly due to difficulty in replacing the bearing. So, I think it can be done but you would need the right kit to do it.  my problem on one of  my CB250K engines  was not the bearing it was the collar that the oilseal fits onto. Due to a period of not being used, the surface was corroded & pitted. I had the hardness of the collar checked and it had not been surface hardened so I did consider getting it machined down to suit the the next O ring ID size, however, I got a full gearbox off eBay in superb nick for £20 so I never bothered.

[mike the bike]

Do you mean that half a ring that fits into a groove?  That just fits into a groove into the crankcase and the groove in the bearing to keep the bearing in place.
It's not held in with anything as such, once the crankcases are bolted up,  it all locks into place.  Obviously it can't be removed without splitting the crankcases.

Hope this helps.

[AshimotoK0]

Think it's pressed on like the CB250/350K. On that bike initially,  the bearing and shaft were available separately but laterally only as a complete assembly due to difficulty in replacing the bearing. So, I think it can be done but you would need the right kit to do it.  my problem on one of  my CB250K engines  was not the bearing it was the collar that the oilseal fits onto. Due to a period of not being used, the surface was corroded & pitted. I had the hardness of the collar checked and it had not been surface hardened so I did consider getting it machined down to suit the the next O ring ID size, however, I got a full gearbox off eBay in superb nick for £20 so I never bothered.

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You will see below what i mean about the CB250/350 TWINS  gearbox parts:  the countershaft itself, less bearing, was available separately with its own part number but latterly only  combined with the bearing as on the 350/400/500 fours

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[ka-ja]

Hi, In the eighties, Mr Honda dealer  showed me the parts manual and the shaft and bearing was only available as a built-up unit.
     I used the seperately listed bearing from the clutch shaft and used heat on the bush and a puller behind the bearing to remove the bearing and the oil seal bush, on assembly, the seal area bush was "sweated" back on, did the job, but not for the faint hearted.

[Gixxer-18]

 Thank you Ash, and thank you too Ka-ja for your information! I think you're right that it is a difficult job; I didn't think it would not be!
I guess it's a tight press fit and a bearing puller might be the answer to removing the oil seal bushing (Collar) and then the bearing, then the gear, if you can get one to fit between the two! Applying enough heat to "sweat" the collar without destroying the bearing is a consideration too.
If a very rusty/damaged shaft is available, and I mean a real scrapper, like chipped splines etc, I wouldn't mind having a go.
Ash your comment about the collar not being hardened is interesting too, i wonder if the old collar could have been drilled and then split with a nut splitter, the bearing or gear replaced, and a new collar heated and shrunk back on?
One of those Honda brilliant simple designs, but a bugger to repair without replacing the whole expensive assembly conundrums.

Regards
Nigel.

[AshimotoK0]

Nigel. ....I have a scrap rusty collared  CB350K countershaft .. I will try it out,  as we have presses here where I work and a MAP gas torch to heat it , if needed

[ka-ja]

Hi, Slitting the seal bush is a no-no unless you can get another one made, I remember putting it back on backwards to get an unworn area for the seal to run on, and I also put a small spot weld at the outer end to make sure it was secure!

[Gixxer-18]

Well I suppose if we don't try we will never know if it can be done? One day one of us will need to replace that bearing, or the collar, at least the bearings are still available! But the shafts? That's another thing! I guess someone with access to a Lathe and a milling machine and the ability to harden the shafts could if they are inclined re- manufacture parts, but most of us are on a budget and working out of their Garage or a shed if they are lucky, and without access to the skills needed to do that. If you are restoring these bike in the future, with parts becoming unobtainable more of us will need to get creative with how we address these problems.
As a Newbie to this forum, Please don't think I'm looking for a solution to a problem that doesn't exist, my original post was how to replace the bearing without having to buy a NOS shaft assembly, out of curiosity more than anything.
Ash, I envy you having access to all that equipment! If you do go ahead with a dismantling, I'd love to hear how you got on!
Regards
Nigel.

[hairygit]

You will notice from previous problems Ash has encountered he always gives a step by step description of how it was done, with lots of good quality photos along with it!

Sent from my X5 using Tapatalk

[Gixxer-18]

I have noticed how diligent he is when he posts, I'm also following him over on HondaTwins, and always look at both sites to see how he approaches solutions. Without people like him taking time out of their lives to help others the motorcycling world would be a lesser place. I'm pleased to know him, and the other regular contributors to these forums, without them I'd be stuck. Probably on the hard shoulder of a motorway.
Regards,
Nigel.

[Orcade-Ian]

I had this problem a while back on my spare 350/4 engine, which is actually the correct number for the bike.
I set to and made one on the lathe from stainless.
I have described the first part of it on my web site under CB 350/4 and it's part 4.
Click on globe under avatar for site,
Hope this helps
Ian

[AshimotoK0]

I have noticed how diligent he is when he posts, I'm also following him over on HondaTwins, and always look at both sites to see how he approaches solutions. Without people like him taking time out of their lives to help others the motorcycling world would be a lesser place. I'm pleased to know him, and the other regular contributors to these forums, without them I'd be stuck. Probably on the hard shoulder of a motorway.
Regards,
Nigel.

Cheers for the kind comments ..but really I should be putting the effort into the day job. Seriously though ( as I do put in the effort real), I just like messing around with bikes, always have and it takes my mind off any other problems in day to day life. I just wish I could stop procrastinating over my CB750K0 and get it put together ...it's becoming an embarrassment now. Hate to admit it but Ralph  (Bitsa)(RIP)  was kind of right that I should be putting my bikes together and not tapping on the keyboard day and night, bless him