Newbie

[meerkat]

but I still get the feeling that the wheel is offset to the offside.  Doesn't this suggest that I might still have the wrong swingarm ?

You posted in your first post that the wheels had been rebuilt. It's possible that the rear could have been laced incorrectly. I have heard of instances of this occurring even with professional wheel builders. I would check this first before committing to another swing arm.
You should be able to spread the fork ends by another 5 mm.

[Oldbuthopeful]

No, it has the open fork ends with removal adjuster 'stops'.

[Bryanj]

That rules out it being an "F" swingarm then, Souonds like it might be bent to me

[K2-K6]

For a basic alignment check you can mount the wheel and sprocket into the frame and put a chain on without the chain gaurd, this should give you at least a first level sighting to assess basic wheel alignment to the frame.

Oh and cross check it to the front wheel as well.

If you have to "reshape it" yourself then a trolly jack between the ends should persuade it but you'd have to satisfy yourself of no kinking or structural damage afterwards. As far as I understand it this is not a heat treatable material so should be able to take a small correction with no problems ocurring and the overall structure when all bolted up is a fairly stable and failsafe one so sensible inspection when back in use would give you peace of mind.

[Oldbuthopeful]

Thanks for all the input, guys.
I'll have a look at the spoke lacing tomorrow.  So you're saying it could account for the perceived offset if it's wrong ?  The outfit that did the wheels are more at home with British classics than Jap ones, so who knows  !

Right, so it's not an 'F'  -  that's reassuring.

Finally, I like the suggestion that it'll tweak or spring by 5mm or so.  I can actually move it by hand a bit but of course it springs back.
I've got a hefty bottle jack and will set that up to give it some 'persuasion'.

I like the chain idea to check the alignment, also the wheel check but as yet, the motor's not in the frame, so the chain's a non-starter but as soon as I get the back wheel in I'll set up a long straightedge.

Many thanks once again.  Usual disclaimers accepted.

Oh, talking of disclaimers, can I mention great service I've had recently from Westfield Fasteners for stainless bolts and from UK Bearings for small quantities of shims in various thicknesses.  No connections and usual disclaimers !

[SteveD CB500K0]

Add them to the "REcommended Sources" board - make sure you add links and contact details.

Steve

[K2-K6]

Wheel offset I read somewhere (could be on here, not sure) but the advice when respoking etc was to measure and record offset of original prior to strip-down and the builder should be able to lace to match this spec.

An easy way to get this is to lay the bare wheel on a flat surface and measure surfcae to rim gap for both sides of unit (i.e. flip it over) and compare to known good example.

looks like you've got enough to work through anyway.

[Oldbuthopeful]

Yep.  Bearing in mind I only registered on the site last weekend, I've had so much genuinely good advice that I think I can now see the way forward on my 550 rebuild. 

I put a bottle jack between the swingarm legs last night and tweeked it to 255mm  -  15mm over the required 240.  I suppose it'll spring back somewhat when I take the jack away.  I'll post the result.

I'd like to show some pics but my attempts so far have been dire.  Lost all the post I'd typed last night so went to bed at 1am feeling like I was a failure.  Trouble is, I was born 20 years too soon for this lark and am struggling to keep up !

Anyway, thanks again, guys.  You're stars !

[meerkat]

Trouble is, I was born 20 years too soon for this lark and am struggling to keep up !

You'll get there quicker than you think.
I bought my first pc at the age of 66 after a quadruple heart bypass (quite a few years ago), it's a steep learning curve but manageable and the start of another age.