Z1A Front Wheel spacing

[MrDavo]

I can’t post photos until I get on the office PC, but I have a problem with my front wheel. Basically I got two front wheels, with speedo drives and axles with the kit of parts I’m building my Z1A from. One is the original, one is from an Z900 A4, which I know is a different hub.

The original speedo drive is seized, though spending tonight soaked in penetrating oil. I have managed tonight to get a tyre and the twin discs onto my newly built wheel, but because of the seized drive I used the one from the A4, along with the spindle. It was all a struggle, the bikes sat on a box at the moment so I can’t lift it clear of the front wheel yet.

My question is, are the spindles, spacers and speedo drives interchangeable? Something isn’t right. When it’s all together the spindle ends aren’t flush with the outside of the fork leg as, it’s all a bit short. It’s only a few millimetres but I know something isn’t right. Also the spacer isn’t hard against anything, again there’s a gap.

I’m sure when I’ve built the callipers I’ll see it’s out of line, but that’s a long way off.

[MrDavo]

Even more confused now, as looking at Dave Marsden’s book, the Z900 had nuts on the spindle, outboard of the fork legs. I think I’ll take the spindle out again, so I can measure and compare the two I’ve got, and the speedo drives.

[Philippe]

Hi MrDavo

the parts are not interchangeable. They're all different, even the lenght of the spacer on the right hand side is different.
Make sure that you use the correct parts or the front wheel won't fit properly between the fork legs. The brake rotor will squeeze against the caliper and the wheel won't turn freely..
Good luck
Philippe

[MrDavo]

Thanks Phillipe. I took it all apart again and compared what I’ve got. I have two identical spindles, 2 identical speedo drives, and one spacer.

I swapped the spindle and speedo drive (the better one now unseized after a night soaked in penetrating oil), exactly the same problem. If I put the wheel hard against the spacer on the offside, I have a 4mm gap between the shoulder on the speedo drive to the fork leg. I could split the difference to 2mm each side, but I know it’s not right. The forks should be parallel, I’m definitely using a Z1 bottom yoke, with the hole for the steering damper, and the top yoke and mudguard fit easily.

This is the sort of problem I was warned about, when you didn’t take a running bike apart yourself and you just trust that spindles, fork legs etc are correct for the bike.

The one variable as far as I can see is the spacer. Mine measures 27.10mm. Can someone take a known Z1 spacer and measure it, just so I know I’m trying to line things up using the right one? Thanks.

[z1bman]

when fully tightened the 2 x 27mm axle nuts do not clamp against the outside surface of the lower fork leg there is a gap. make sure you speedo drive & spacer are flush against the inside surface of the lower fork legs

[z1bman]

this is a z900a4 spindle & nuts

https://www.ebay.co.uk/i/331834749822?c ... gLwOPD_BwE

this is a z1a spindle

https://www.ebay.co.uk/i/311254634998?c ... gJsPvD_BwE

[MrDavo]

What I’ve got is definitely Z1, no nuts on the outside. Maybe the fork legs are the problem, I certainly hope not.

My spacer looks like Z1, not the A4 one with the step, I’d still like the measurement to be sure. Things could be put right with the right washers perhaps, but I’d still like to get to the bottom of what’s wrong. Also even if I split the difference evenly to 2mm each side, I’m still going to have a problem lining twin callipers up with the discs.

[z1bman]

personally i would say the spacer is too short or not correct for the bike pictures would be a help ?

[MrDavo]

The spacer looks exactly the same as in your links, and came on the spindle. The witness marks from the oil seal look to be in the right place too. However I measured the length, that’s why it would help if someone with a Z1 in bits could measure theirs for me.

I’ve been wondering about fork alignment. There are now two cable guides between the fork leg and the mudguard, could that make a difference? They do go between the mudguard and the fork leg, yes? Either way I might try taking the mudguard off, then tightening up the fork caps. The other thing I can try is putting the lower yoke bolts in and tightening them. They are in a box of parts about to go off for chroming, possibly tightening them only needs to pull in each leg 2mm towards each other and the problem will go away. I can do up the wheel mounting and then take the bolts out again as we are ready to go to the chromer.

[Gus]

If it's any help

Z1A



Z900



Gus

[MrDavo]

The first picture all looks the same as what I’ve got. Bearing 4 is hard against circlip 3, so in the right place and defines the gap from wheel to fork leg.

Here's a photo of the gap, between the spacer and the fork leg, this is with the shoulder on the speedo drive hard against the other leg, obviously I can move the gap across, or halve it and have a bit of a gap either side. The polish marks on the spacer seem to be from when the chrome cover was fitted, rather than a second disc.



I'll tighten up the yoke bolts tonight, with the mudguard removed, and let you know what happens.

[z1bman]

its a possibility the fork is slightly bent

[MrDavo]

See my thread in 'projects' - Phillipe has come up with spacer measurements, mine is 3.5mm on the short side. Mystery solved, by the look of it

Now to find the right part 41069018 according to the parts book. Johnny's in the US has them if I can't find one nearer. Thanks again this board is a mine of information.

[z1bman]

try john browse in wrexham


11 Poyser Street
Wrexham
Get Directions

m.me/JBrowseMotorcycles

Call 01978 355556

[MrDavo]

I just went in the garage for a look, as well as the spacer issue, when I put the speedo drive shoulder hard against the fork leg, the thick ‘stub’ doesn’t seem quite long enough, the outside end isn’t flush with the outside of the fork leg by a few mm.

I’ve decided to bite the bullet and ordered a complete used Z1 axle, spacer and speedo drive set from D&K. Even though I’ll then have 3 Front spindles and speedo drives, I should be able to remove doubt by using parts known to fit.I've found their listings to be reliable in the past, I guess the secret is to label parts as they break the bikes for parts. I can always sell the left over parts if I advertise their dimensions so buyers can work out for themselves if they’ll fit their bike.