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[jefrs]

Thanks everyone. Thanks again Ric. The back end didn't feel loose enough to be anything obvious giving it a heave (the rear wheel flexes nicely) but I did get almost a full turn on the nylock swingarm nut on the torque wrench, without which I would have over-tighened until the bike came off the ground

Not exactly loose but enough to indicate it was the probable cause. The little clunk I have felt I previously assumed to be the bike skipping out, which it could still be, but it's an unexpected twitch. I checked the shocks in the process. Likewise the rear wheel spindle was previously done up by me and I'm part gorilla so that's tight (also 7kgm).

An axle turns but a spindle is static. All the 1/2-in and M10 bolts are torque to 7kgm, engine mounts, front and rear wheel spindles, and the swingarm. The swingarm bolt though is an interference fit in its tube/spacers/bushes, it has to be knocked in and out. The swingarm bolt does seem a bit flimsy, it's nowhere as thick as the steel bar on a BSA, at least it can be got out though



I have not tested it yet, whilst I'm happy making a car slide I try to avoid that on a bike. Now I'm fairly sure it's not the tyre I'll just have to run it around to to see if it happens again, before investigating suspension travel. It wasn't bottoming out, that has happened two-up with the springs set weak (Do try two blokes on a Bantam, bottoming out is normal). But it could be the other end of travel (thanks Scaley).



p - the spindle is a long bolt, I had to put sockets on both ends to stop it turning, the big torque wrench on the nylock. The plastic inserts don't look very proper but at only 2500 miles I don't think they can be completely shot yet.

[PeteF]

Sorry Jefrs. Definition of axle from OED;
A rod or spindle (either fixed or rotating) passing through the centre of a wheel or group of wheels.

[PeteF]

"the rear wheel flexes nicely"
????

[Adam]

Could that little ‘clunk’ you felt be the anal sphincter urgently doing its job?

[jefrs]

PeterF, I'm strong enough to flex a perfectly good bike wheel in my hands. Spoked wheels are supposed to flex as part of the suspension, they're springy, and hence we fit alloys for a more rigid wheel. If you grab and heave the wheel to test the swinging arm, expect a spoked wheel to flex.

[jefrs]

Adam, no brown trousers involved.

[Dennis C]

????????.

[PeteF]

As you say Dennis.
Never heard of flexible spokes before.

[jefrs]

PeteF, have you never rebuilt a bike wheel? The rim is suspended from the spokes in tension at the top of the wheel but at the bottom of the wheel the spokes are now in compression from the weight of the bike, the nipple is attached in tension (it's a nut) so it can push into the rim as the rim deforms, it is intended to do that, the rim is a spring. There's an art to lacing spokes up, I'll do it if I have to true a wheel up otherwise I'll throw the job at a wheel builder. As for bending spokes, you don't bend the spokes, they're attached by a hook at one end and a nut at the other, they hinge or pivot on those two points. It takes a fair bit of force to flex a spoked motorbike rim but it is doable.

[Dennis C]

Thanks for that information jefrs, I have rebuilt dozens of wheels both for myself and for other VMCC members and I never knew that. . I wish I was clever like you.