Wombat 94 Cush Drive

[Bill2001]

Going thru my new-to-me '73 Wombat 94 I've finally come across a part worn enough to warrant replacement. The ball bearing (part ID 59) in the cush drive hub (part ID 58) in the referenced parts diagram. Bearing has not failed yet, but it's rough as a cob.

Parts diagram "S"
http://www.strictlyhodaka.com/Parts-List-S2-s/2121.htm

I want to get the bike on the road this week, so I'm going to get a local bearing replacement. My parts manual gives a part# of BB6204, which suggests to me a good ole 6204 bearing, which appears to be just a shielded bearing. Grease seal #61 seems to be a triple-lipped seal designed to keep the worst of the mud and water off the shielded bearing. I think I can extract it and reuse the seal til I can get a replacement (if I can't get a local off-the-shelf replacement). With the 6204 bearing I'm inclined to get a sealed (instead of shielded) replacement. Manual is non-detailed about this repair, but I'm guessing pop the seal, remove snap ring #60, heat the hub and tap the old bearing out. Reverse to reassemble.

Sound like a good plan?

Otherwise, the wheel bearings and wheel bearing seals and brake parts look good, though the bearings are in line for replacement next year ( they are 40 year old 6202's and cheap enough not to mess with). Shoes are new, drums are not scored.

--Bill

[socalhodaka]

Yes sounds like your on the right path. I get my bearnings and seals local also.

[Bill2001]

Got the bearing and seal today-- stock items at the local industrial supply. The new seal is single-lipped and 7mm thick but the old original seal is double-lipped and 8.5mm thick. I suppose it will do, I'll be servicing the wheel bearings in a few months and I'll replace this new seal with a double-lipped seal. Or if it's that critical I'll get a double-lipped seal tomorrow.

Yeah, I'm a picky wrench sometimes.

I just noticed this and I'll check it out later tonight: on the entire axle stack-- everything from the right chain adjuster to the left chain adjuster I found an extra washer maybe .040 to .060" thick placed between the left axle collar and the chain adjuster. How much clearance should there be between the R or L axle collar before the axle nut is tightened? I'm thinking that -zero- is ideal but a few-tens-of-thou would be OK.

I like this old bike. First UJM I've owned since I was a kid and I appreciate the marvelous simplicity in the engineering.

--Bill

[Bill2001]

I picked up a double-lip today-- given that this is a dusty. muddy, wet service area a double-lip will work better. 47x28x8mm for the cush hub outer seal. Between the cush hub and the wheel hub is an o-ring, 47mm ID x 3.5 thick. Since the cush hub is torqing back and forth on the o-ring I'd imagine that a dollop of waterproof grease on the o-ring is a good idea.

Didn't get a chance ti fiddle around with that axle/bearing stack on the rear wheel.

--Bill

[Bill2001]

Here is a closeup of the rear sprocket. Odd wear, only on the _inside_ of the sprocket. From the wear on the chain rollers and tooth pockets on the sprockets there isn't a lot of mileage on them.



Not having done much with drive chains over last few years, I'd hazard a guess and say that the rear wheel adjustment was off-- wear on the right side of the sprocket, wheel angled towards the left. Sprocket is still useable.
I've not looked closely at the chain side plates (#428 chain, 5/16 roller width and sprocket thickness) so I wonder if the chain could be compromised? I'd prolly look for loose side plates or evidence of loose rivets.

Old bikes. Ain't they fun.

--Bill