Tapered bearings leaving little thread for the head top

[Winterfield]

Hi all,

I'm progressing with my ground up rebuild, and I am tantalizingly close to having a rolling chassis.

I've replaced the steering head bearings with tapered bearings (All Balls I think).

The problem I'm having is that I suspect I didn't clear up the frame well enough before pushing the bearing sleeve in. This left approx a 1mm gap you can see in the photos.

This is causing the thread top to have very little thread to turn onto. It's turning approx 360 degrees before it's tight.

My question is: how important is it that this part is torqued down? Does the steering nut provide the torque to tighten everything up? Or does the head top thread need to torque down more than 1 turn?

What's the proper technique for pushing these bearing sleeves in?

[Winterfield]

Aha, yes, I was wondering.

I followed the advice of a forum post somewhere and used the larger spacer. Of course, now I can't find the post to confirm.

I'll knock the bearing off the yoke and try the thinner spacer.

[SumpMagnet]

Are those bearing seats both the same height? Looks like the lower one is recessed right into the headstock and the upper one sits proud.

I suspect you have been advised on using a spacer as you might get clearance issues.

But....correct torque on that lower nut is critical for steering. Too loose, and it will wobble.. too tight, and you will get weaves and low speed steering issues.

[Winterfield]

I can definitely see that the torque on the lower nut is critical, and that's what worries me. In order to get a couple of the threads to bite I have to torque it down a fair bit (i.e. even just a 360 degree turn of the nut).

I suspect that if I have this gap between the frame and the bearing seat on the bottom, then I can compensate by using a thinner spacer on the yoke (assuming it doesn't bind against the frame. Trial and error may be the way forward here.

[Sprocket]

I had exactly the same issue at the weekend! Same kit, same fit. I followed the instructions in the kit and measured the stack height of the bottom race. If you have a thinner washer in there it will definitely bind at the bottom of the head tube - so that's not the answer.

I thought about not using the bearing seal, then not using the washer that sits above it, then getting a thinner c-spanner nut.

Eventually settled on using the original c-spanner nut with the shroud ground off, upside down, directly onto the kit seal. It's not ideal, but I'd estimate there is a thread in the entire nut. Certainly enough to properly torque it down.

I've not completely reassembled yet (got the wiring in, just need to put the brake, mudguard and wheel back) and then I'll follow the Haynes procedure to adjust the tension on the head bearing.

[K2-K6]

That looks to be fitted incorrectly to me. In every kit I've ever fitted the seal went at the bottom not the top, the shroud on the C spanner nut provides the protection for the upper race. Normally the seal would go on the bottom yoke first and then maybe a spacer and then the lower race. If you look at the seal you can see it's lipped around the edge which would seal against the frame tube when it's fitted, doing nothing there on the top yoke.

Agree with above,  that rubber lip seal inside the bottom frame aperture to prevent ingress of weather into bearing space.

They where "spaced" one way or another with that seal included to let it sit inside the frame tube,  plus give clearance for the fork yoke to not interfere with the frame. 

The top track on these new one's appear to sit too high in the frame from the photos.

Originally I think the bottom one was made from a Timken bearing that fitted the fork stem but was oversized for frame dimension,  and had to have the outer track machine ground to give a bespoke fit. 

It doesn't look correct with these posted now as it shouldn't be bringing the top yoke up.

[Sprocket]

Regarding the bottom races and seals, yes, it goes washer > seal > race. In my pic you can see the seal up top, but they do make a good internal seal to the race that's difficult to see sideways on. If I'd known I'd need a pic I'd have taken one!

All told, *my* setup (your mileage may vary) puts the top yoke at exactly the same height as was with the standard bearings. I made a specific note of checking the shoulder of the top of the fork tube was in the right place, prepared for it being a weenie bit high or low, but it's exactly right.

[Sprocket]

Sometimes I love being prepared, photo attached....

Top seal, bottom seal (note the internal diameters) and two different thickness lower race washers (should be called shims, but I'll let that slide....) and one upper.

Because Saturday night Sprocket is an absolute rockstar you can see the instructions with this kit that tell you about the lower race too.

[Winterfield]

Taking the top seal off would likely give me the clearance I need. I was using the thinner shim on the yoke, but I tried without the shim and got the binding on the frame as expected. Unfortunately, I mangled the bottom seal while experimenting.

Sprocket, you wouldn't happen to still have the packaging with the product code for just the bottom seal would you? I couldn't make it out from the pic.

[Winterfield]

Looking at the original Honda parts list, there's a bottom dust seal, and no top one. Shame I mangled my bottom seal when all I needed to do was remove the top one.

[Sprocket]

Sprocket, you wouldn't happen to still have the packaging with the product code for just the bottom seal would you? I couldn't make it out from the pic.

Well yes! Trouble is I also have the packaging for the top seal and they are both empty! They are 33-1024 and 33-1007 (Think this is the bottom one, larger ID, on the left of my photo)

[Winterfield]

That's great, thank you. I'll see if I can find a UK supplier who will send me just the seals.

[Erwin83]

Just installed new bearings on my 350f (All-balls kit) last weekend, and this link was very very helpful. Thanks for sharing!

I used the smaller spacer (of the 2 options) at the bottom after measurement of the bearing, spacer and seal stack as described in the link.
At the top, I was able to use the seal, spacer (as All-balls manual describes) and top nut with the curved down cover attached.
Agreed, there is much less thread left than originally, but still a comfortable 1,5-2 full turns. Enough to properly tighten it down.