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Steering head bearing fit


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Sew...

Today the front end came apart, and I found what I suspected but didn't want- the steering head bearings are 52mm, and the holes in the frame are between 52.20 and 52.65mm. This thing's had a clunk under braking since I bought it that I couldn't reproduce by hand or rocking, only shows under braking. 
I guess I'll clean it up and see if I can drive it all back together with some shim stock or a speedi-sleeve, or I'll have to use heavy loctite bearing retainer and deal with the results. 

 

Frontend.jpg

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Sew... you have the races out and the bores in the frame are slightly bigger than the outside diameter of the races? And possibly oblong?

Sorry I don't have and advice to contribute, but I'm curious to see how this can be addressed.

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3 minutes ago, Scud said:

Sew... you have the races out and the bores in the frame are slightly bigger than the outside diameter of the races? And possibly oblong?

Sorry I don't have and advice to contribute, but I'm curious to see how this can be addressed.

In a perfect world, I'd completely disassemble the frame, clean it, spray weld the bores and resize them in the machine shop.
In this world, I've put ~15k miles on it as it is and I'm not ready for a complete restoration yet. So the options are *all* sorta backyard shadetree answers. 
I'll clean it up and play around with the bearing races and feeler gauges, to see how much clearance I have in what areas; then I'll average out the clearance, use feeler gauge blades to bring the size back to a reasonable tight fit, put everything back together with a hard bearing bore adhesive loctite product and run with it until the day comes when it gets ripped to the last fastener. 
I'll take the forks to the local KTM/WP center and have them give a look, but these forks may be older than their technicians...nothing wrong with them really so if they can't or the price is too high, I'll renew the fork oil and clean them up myself. The springs as is are good for my weight, and they don't leak so...meh. 

On to the brake caliper rebuild.

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1 hour ago, Pressureangle said:

Sew...

Today the front end came apart, and I found what I suspected but didn't want- the steering head bearings are 52mm, and the holes in the frame are between 52.20 and 52.65mm. This thing's had a clunk under braking since I bought it that I couldn't reproduce by hand or rocking, only shows under braking. 
I guess I'll clean it up and see if I can drive it all back together with some shim stock or a speedi-sleeve, or I'll have to use heavy loctite bearing retainer and deal with the results. 

 

Frontend.jpg

I would expect some variation due to the distortion created by frame welding but yours seems to have more than I've experienced of would expect. Has it ever had a front end crash? I'd just use some Loctite bearing mount and if you ever need to remove them then you can just run a bead of arc weld around them on the inner face and they'll fall out even with the loctite.

Ciao 

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8 minutes ago, Lucky Phil said:

I would expect some variation due to the distortion created by frame welding but yours seems to have more than I've experienced of would expect. Has it ever had a front end crash? I'd just use some Loctite bearing mount and if you ever need to remove them then you can just run a bead of arc weld around them on the inner face and they'll fall out even with the loctite.

Ciao 

There's no evidence of a crash, I've measured the alignment best possible with straights and levels and it all appears to be square. It tracks perfectly, not as if it's had it's rake reduced. Without any specific reason, I'll attribute it to Italian tolerances; the major diameter of the bottom race bore is *not* along the frame axis. 
As you said, I'll take up what space I can with some shimming, and add bearing mount to perfectly clean surfaces. 

With the clunk identified and corrected, and the brakes working properly, perhaps I can keep up with Docc at the Spine Raid. ;)

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10 minutes ago, Pressureangle said:

There's no evidence of a crash, I've measured the alignment best possible with straights and levels and it all appears to be square. It tracks perfectly, not as if it's had it's rake reduced. Without any specific reason, I'll attribute it to Italian tolerances; the major diameter of the bottom race bore is *not* along the frame axis. 
As you said, I'll take up what space I can with some shimming, and add bearing mount to perfectly clean surfaces. 

With the clunk identified and corrected, and the brakes working properly, perhaps I can keep up with Docc at the Spine Raid. ;)

I wouldn't worry about the added complexity of the shimming the Loctite will tolerate that gap from memory and has the psi rating to deal with the loads.

Ciao

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Just musing here, but If the headstock bores are concentric, you "could" have the OD of the races plated so as to match them more closely to the headstock. 

As I said, just musing.

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4 hours ago, po18guy said:

Just musing here, but If the headstock bores are concentric, you "could" have the OD of the races plated so as to match them more closely to the headstock. 

As I said, just musing.

Quite out-of-round. Still I could spray-weld the race OD and make it round with the hammer. But that's no more a true fix than the loctite, and a lot more work and cost.

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It most likely was not bored out of round, so was pounded out of round. I don't suppose that anyone has a hydraulic mandrel handy that would compress the bearing cavity back to spec, so perhaps a machine shop or bike frame shop could bore the steering head out, but then how to find an over-size race? I suppose that you would have to machine a shim and Loc-Tite it into place. Q: Would J-B Weld be sufficiently strong to fill the gap? Even if it failed, it would be no worse than before.

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So there's an official WP service center about 20 minutes from home- the local KTM/Husqvarna/GasGas dealer. I was going to call, but drove over instead; asked 'hey can you do these old WP forks?' he says, 'sure, what are they from? Bring them in' So I bring them in to the counter, he looks weirdly at them and asks again what they're from. I tell him, '97 Moto Guzzi. He says, 'you won't believe this but I have forks and shock apart on the bench in back from a '97 Moto Guzzi.' 

So is there a forum member from Miami who brought their stuff up to Stuart? 

$125 plus parts for the forks, $150 plus parts for the shock (later) He asks, 'You want these cleaned up? We can vapor blast the feet and they'll look like new' Well, surely. Glad I didn't fool with them on my own, anyway. 

...and while waiting, the kid fell for and bought a Svartpilen 401 lol

PHO_BIKE_90_RE_svartpilen-401-my22-90-right_#SALL_#AEPI_#V1.png

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I hope both your bikes are bound for the Eighteenth South'n SpineRaid !!   :race::pic:

So fortunate on the local WP service! :luigi:  :thumbsup:

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That Husky 401 is a seriously fun and crisp-handling thumper. I rode one on a demo day recently.

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