I'm puzzled...............

[farmer58za]

Hi guys
The rear wheel bearings on my '75 KTM 400 are shot so I bought some new ones and whipped off the back wheel. The bits that came out of the hub centre look like what's in the manual ('74 Penton) but something doesn't match up. On the non-drive side, there were TWO bearings, one on top of the other, with the outer bearing flush with the machined hole in the hub. On the drive side there was a single bearing fitted between two circlips. The hub centre axle spacer looks stock and is 64 mm long. Everything fits together nicely in the swingarm. The manual only shows one bearing per side. Did the hub change for '75? There must be something I'm missing here....

Confused David (who wants to ride Saturday)

[Rocket]

David
Do you have a conical rear hub?  From what I have seen here in the states, all the conical hubs have one bearing per side.  The full width hubs, used on the 100's, 125's and the early 175's had 2 bearings per side in the hub and 2 in the sprocket carrier.  Maybe your hub has been modified or??
Rocket

[farmer58za]

The plot thickens:-

I've noticed that the outer bearing of the pair on the non-drive side is a loose fit but the inner one is tight. All I can imagine is that the previous owner noticed the same and shortened the spacer on a lathe by one bearing width before pushing in an extra bearing that would fit tight on the non-worn hub surface further in.

Are these hubs prone to wearing like this?

David

P.S. the hub is stock conical KTM

[Doug Wilford]

Your logic sounds reasonable.   In fact the previous owners modification has probably made the hub stronger.    If it worked for him I am sure you should have no problems, maybe a 1/4 a kilo heavier.  Go ride and have fun.

[farmer58za]

Ok, so this is what i'm doing:-

I've cleaned and roughened up the bearing housing and spread some epoxy around the worn section. I'll rub this back with wet/dry until I get a tight fit for the outer bearing as well, then put both bearings back on that side.

Tomorrow, I ride with my nephew who has a '79 IT 175 which we bought and fixed up. I think they can appreciate the bike more if they've had a hand in the fixing process.

Enjoy the weekend guys.

David (enjoying summer in the southern hemisphere)

[Doug Wilford]

Your logic sounds reasonable.   In fact the previous owners modification has probably made the hub stronger.    If it worked for him I am sure you should have no problems, maybe a 1/4 a kilo heavier.  Go ride and have fun.

[farmer58za]

Ok, so this is what i'm doing:-

I've cleaned and roughened up the bearing housing and spread some epoxy around the worn section. I'll rub this back with wet/dry until I get a tight fit for the outer bearing as well, then put both bearings back on that side.

Tomorrow, I ride with my nephew who has a '79 IT 175 which we bought and fixed up. I think they can appreciate the bike more if they've had a hand in the fixing process.

Enjoy the weekend guys.

David (enjoying summer in the southern hemisphere)