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Old 01-02-2011, 02:29 PM   #68
BergDonk OP
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Joined: Nov 2010
Location: Snowy Mountains Oz
Oddometer: 3,719
Originally Posted by BergDonk View Post

I trusted LukasM on his advice re the steering head bearings, and it works so far, ie keep the Suzuki cups in the steering head and the KTM races will line up. the bearings are sized differently, ie 29 x 50.25 x 15 KTM vs 30 x 52 x 16 Suzi but it seems to work OK. The rollers are in full contact with the cup. A couple of shim washers to lift the top clamp to clear the damper post mount and we shall monitor durability. May end up fitting a sleeve to the KTM shaft and just use the Suzi bearings, dunno.
I also got 2 sets of head bearings, just in case, but as yet unused from ebay for about $100
So after a couple of shakedown rides of about 60 kms each my brother and I met up with Snowy last Thursday and we did about 220 kms. Checking the bike over on Saturday after the ride revealed some play in the steering head bearings. The KTM bearings that came with the triples had a little corrosion on them so I knew their life would be limited, but I thought they would last longer. I pulled it apart after an attempted retensioning revealed that they were stuffed, there were large indentations in the cups of the bottom race.

With a new set of each bearings in the shed as noted above from the same manufacturer, I thought I'd just fit it together again with the new bearings. The new bearings however did not match, ie the KTM race did not match the Suzi cup, the taper being obviously different, perhaps 5 degrees. A close look at the damaged bearings identified that the the taper here was slightly different too, but not as much as the new ones, and perhaps only 1 or 2 degrees hence I didn't really notice it first up.

What to do? 2 options, sleeve the KTM shaft to take the 1 mm larger ID of the Suzi bearings, or pack the KTM cups with a sleeve to match the Suzi steering head, ie 50.25 needed to equal 52 OD. I decided on option 2.

I started out with a 50 mm long piece of 60 mm OD mild steel bar and made lots of swarf. This pic is just after parting off the first sleeve.

Close enough!

Fits perfectly, no adhesives or dimpling required, a bit lucky I guess, as I've never done anything like this before, so I challenged myself.

Just had to change a couple of shims under the top clamp when it all went back together and a short ride to bed them in and check tension and should be good to go.

My conclusion is that its best to have one bearing set or the other, and that different bearings may or, may not, match up. Mine didn't match.

So the one thing I wasn't too sure of has now hopefully been addressed.


EDIT I've changed this a bit, see post 206 by scrolling down here:
shed time IS quality time
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BergDonk screwed with this post 08-20-2012 at 03:01 AM
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