Saturday morning: a mini milestone

After months of painstaking work (or fanny about, if you prefer), the rear suspension, wheel and drive were finally reunited in perfect harmony. That means she can be rolled around again, albeit in minimalist stripped-down form.

Well, OK, that might be a bit of an overstatement but still it was a big moment for me to be able to wheel wonderful Wuby awound again.So, to celebrate, I did a couple of little walk-around movies.

From the left:

and from the right:

Beautiful smooth running drive chain action:

It's amazing how light a big bike can be .... when half of it isn't there!

Utterly horrible

I'd meant to post 'before' pictures of the drive sprocket and its housing with the 'after' pictures from my last post. Externally, things weren't too bad. Underneath the slight patina of age that adorned the sprocket cover, it was a whole different story.

 

Removing the sprocket cover revealed an utterly horrible sight: years of sticky chain lube plus road dirt and metal particles from the terribly worn sprocket, all packed tight around the chain and clutch pushrod.

I scraped all the muck out into some old newspaper, with judicious use of a large screwdrive. I swear, it must have weighed a kilo - like a generous portion of fish and chips.

The sprocket was loose on the gearbox output shaft - the lock washer was the only thing that had stopped it coming off altogether. Nasty. At least I didn't have to fight to remove it.

Although I've seen pictures of teeth in worse condition before, I'd never come across a sprocket with more wear than this myself. The teeth were no more than a third of their original width and distinctly hooked. More like barbs than teeth. Here's a repeat of an 'after' picture for easy comparison.

Reassembling final drive

I decided to gear the bike up for a lazier ride. So I got a 19 tooth gearbox drive sprocket, one tooth larger than standard, and a 42 tooth driven sprocket. 

It is impossible to torque up the gearbox sprocket nut to the required torque of 132NM without being able to stop the sprocket from rotating. I have found the best way to do this is to put the gearbox into first gear and to hold the rear brake on. That way, the gearbox sprocket is held still by a combination of engine compression and brake pressure. So it was time to fit the rear wheel.

Mushroom type spacer on right
of wheel. The wide end butts up
against the rear brake bracket

Rear wheel spindle, spacer, rear brake
bracket, bush and wire retaining clips

The rear wheel fits onto its axle between a small alloy spacer on the left and two spacers on the right.  The right-hand spacers are a large, mushroom type spacer that fits into the rear wheel, and a large aluminium bush that fits into the centre of the brake bracket.

The rear wheel, fitted with sprocket carrier and small, left-hand spacer, has the chain looped over its sprocket pushed well forward to maximise chain slack. The eccentric chain adjusters should also be turned so they are aligned to the same marks on the swingarm and pushed slightly outwards from the centre of the bike before being nipped up with an Allen key. This makes the gap for the rear wheel as wide as possible to help you get the axle through. It's easier to see what's happening this way.

The rear wheel spindle needs to be fitted from the left because it is isn't easy to manoeuvre the wheel into place, and the sprocket carrier side is the heavier of the two. I put a wooden block under the wheel to help support the weight.

Greasing the large aluminium
bush for the centre of the rear
brake bracket

Axle right through, bolt being
wound home. The gap between
eccentric adjuster and brake
bracket is visible here. 

I used plenty of Castrol LM on the mating faces of all the spacers, the brake bracket bush, and the axle itself. With a  bit of wiggling and the assistance of a rubber mallet, the axle through each of the components in turn.

The right-hand bolt is wound in with at 12mm Allen key, pulling the swingarm legs together against the spacers. I nipped up the axle bolts at this point before slackening off the eccentrics to adjust the chain tension, and to allow them to move inwards to their correct position.

132NM of torque for the gearbox sprocket

I refitted and bled up the rear brake and then was ready to torque up the gearbox sprocket.

It worked a charm but needed a steady hand and my largest socket (36mm). That just leaves the flattening of a tab on the gearbox lock washer  - that done, job's a good un.