Rear drum

[allankelly1]

Hi all

Went to change my rear shoes today as brake has started to feel not right and found that on fitting the new shoes / brake plate there was a tight spot and on closer inspection the rear drum lining has a very small hairline crack and you can feel a slight bulge to it

So question to all is please

Either does anybody please have a spare good rear hub they were willing to sell or can I get the hub relined  somewhere in the uk?

Any advice most welcome

Many thanks in advance to all

Best wishes Al


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[Nurse Julie]

You can get them re lined. Graham, Trigger, used to re line them for customers and our own bikes but doesn't do it now unfortunately. I'm not personally aware of anyone else that does it now but there must be someone in UK. There was a chap in Huddersfield, Terry I think, be he has retired.

[SteveD CB500K0]

Ask Bryan Jones (BryanJ)


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[allankelly1]

Hi Julie

Thanks for the quick reply

I was thinking there must be somebody who can do this in the Uk but question is who?

Will see if anybody else has a possible lead

Oh well at least it’s getting towards winter so it not got in the way of summer

Thanks again Al




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[allankelly1]

Ask Bryan Jones (BryanJ)


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[allankelly1]

You can get them re lined. Graham, Trigger, used to re line them for customers and our own bikes but doesn't do it now unfortunately. I'm not personally aware of anyone else that does it now but there must be someone in UK. There was a chap in Huddersfield, Terry I think, be he has retired.

Hi Julie

Looks at another thread and I see trigger used a donor brake drum from a motor factor for the repair and then bore out the old cast in ring then turn up a drum sleeve to suit the bored out sleeve and then shrink fit and finally then pin it in place and then do a final bore to ensure it was true

I also see that the brake drum diameter is about 160mm

Just thinking as I am a toolmaker with access to a lathe what donor drum please did trigger use and what was the interference fit etc he used?

Any info you or trigger can share regarding the repair would be most welcome so I can see what is involved should my search not turn up anything

Best wishes and thanks Al


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[Bryanj]

The 400 drum does not crack up as often as the 500 so probably your cheapest/easiest answer is a used wheel from another 400. It was Paul in Huddersfiel, i had several 50's done  but as Julie said i believe he has retired.
If you remove the rim and spokes any decent machine shop should be able to machine it out and fit a liner IF they can find the cast iron to do it

[Bryanj]

There should be a max dia measurement inside the drum

[allankelly1]

Hi Bryan

Thanks for the reply

I think the PO had the bike standing for a long while  and looking at the drum internals maybe water has got between the drum and hub and started to rust as is a nice bulge on closed inspection?




But as winter is on the way me thinks that I should  repair the drum myself and not be a lazy bugger

Got no problem doing this as I am an ex toolmaker with the skills and access to a lathe etc

Also saw how trigger pinned the drum as extra security after

So I have asked trigger what donor drum he used so I can source a drum that is the correct sizes so I can then plan to bore out the old cracked sleeve and then turn up a new sleeve to replace the cracked one etc

Best wishes Al


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[Bryanj]

That pic is exactly what the 500's do.

[allankelly1]

Maybe just maybe



Hub is currently scrap at the moment and it would match my front end brake modifications upgrade I did last year



Just need to design and machine up and fit inside the drum area and secure in placed a custom disc carrier

Looking at callipers themselves a CB750 four would match the front end




And then just need to sort out a caliper hanger and remote master cylinder set up

 Winter is on its way and bike is now off the road till sorted and need another project to go with the 460 engine build during winter hibernation

Happy days

Best wishes Al


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[K2-K6]

"Just thinking as I am a toolmaker with access to a lathe what donor drum please did trigger use and what was the interference fit etc he used?"

Thinking small car drums as scource material, maybe if you've a friendly motor factor to let you see stock items. Or something like trailer stuff,  indespension or caravan drums are in that range.

For disc conversion,  the original Yamaha RD400 (with twin piston calipers,  not floating single) had a pretty neat caliper hanger with brake top and torque arm located in similar area to the Honda drum one, that could give options or design que.

Twin piston for rear is easier for alignment as once designed you don't effectively have to cope with pad wear further on.

[allankelly1]

"Just thinking as I am a toolmaker with access to a lathe what donor drum please did trigger use and what was the interference fit etc he used?"

Thinking small car drums as scource material, maybe if you've a friendly motor factor to let you see stock items. Or something like trailer stuff,  indespension or caravan drums are in that range.

For disc conversion,  the original Yamaha RD400 (with twin piston calipers,  not floating single) had a pretty neat caliper hanger with brake top and torque arm located in similar area to the Honda drum one, that could give options or design que.

Twin piston for rear is easier for alignment as once designed you don't effectively have to cope with pad wear further on.

Hi thanks for the info

Really started to think about the rear disc conversion so for now going to go this way

Just ordered a cb400n disc like I have up front and then when it arrives planning to design and 3d print a prototype disc carrier

If all looks good and the conversation looks feasible by refitting the rear wheel with the prototype carrier and disc in its final place I can then sort out and caliper and torque arm set up again printing a prototype

Then if all look so I can commit to metal parts and go from there

Best wishes Al


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