Topic: CB350 fron drum steel liner replacement

[AshimotoK0]

Got three of the CB250/350 K front drum hubs with the extra 'blind' spoke holes in, specific to K0/K1 models plus one later one. Problem is one K0 one has a cracked liner. Anyone know how to remove the cracked one and is it possible to swap them, as the later front hub one is fine. I do have access to a lab oven that goes to 450 degrees Centigrade . Other alternative it to CNC the 'blind' holes in the later one.


library picture of 'blind' hole drum attached

Ash

[754]

Generally. Not removable...it can be done but because of the huge liability issues, some that can..will say they won't..
 Is it worth it? Better be a pricey hub..

[AshimotoK0]

I suspect that the hub was cast onto the liner as there is alloy flash on the exposed circumference of the steel liner, so not really an option to swap but there are several guys in the UK who will machine and shrink in a new steel liner. (it was also a problem on the CB500/4 I believe). These K0/K1 parts are fairrly cheap & plentiful in the USA but like rocking horse poo in the UK and because they are rare UK sellers demand I a high price. Plus a lot of front wheels on the CB250K0 & early models suffered liner cracking, I experienced it 'back in the day' on my K2. Shipping and customs and tax plus handling fee over here usually makes buying from the US a very expensive option now.

We do have a CNC milling machine here so I think I will get a cutter ground and attempt to machine the blind holes myself in the later one. It's for my JDM replica anyway so a bit of a longer term project.

Ash

[754]

I think you could probably machine til, most of the cast iron came out, and you have a relative flat surface...then cut about 6 or 8 1/2 round notches further in..about maybe 5 mm.
 Them measure the major dia,  add a few thousand for press fit.
 Use that dia for the machined band of cast iron,  with the halfround projections on it to machine the hub... Lots of work..