Scottish apprentice einzylinder mechanic has self doubt

Begonnen von † Norrie, 15 August 2014, 19:53:15

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† Norrie

The bevel box rear drive housing on my R25/3 project was damaged. Dents and chips out of the casing and deep scores on the inner hub side through a wheel lockup. I did have a good replacement housing (same part number) and rebuilt it using my original cover, still sound bearings, crown wheel and pinion, new gaskets and seals and subsequently fitted it to the frame thinking all was well.
In the meantime I had cleaned up the wheel hubs and rims replacing the bearings with taper rollers. I rebuilt the wheels using stainless spokes and having had them checked by a proper wheel builder ground off the protruding spoke ends and fitted new tyres. I was then keen to fit the wheels to the frame/forks and have something that looked like it might, one day, be a motorcycle and anyway a rolling chassis is far easier to work on.
Tightening and slacking the nut on the rear wheel axel made some interesting crunching sounds from the casing area - 'Oh dear!' I thought'. :kopfhau:
Remembering what I had read about the accuracy involved in the initial assembly I thought I was going to have to take the plunger/rear drive housing out of the frame, pull it apart and check everything I've done and possibly fit a thicker shim behind the inner crown gear bearing. I had carefully measured the depth of both casings bearing recesses and was positive everything had gone back together as it should in the good casing.     
I ignored the problem for a while and got on with other jobs. I eventually realised that I could swap the wheels over and see if the noises persisted as an alternative to immediately opening up the bevel box. Before I did that, with the wheel spindle through the hub, I slipped a box spanner and washer onto the spindle and tightened it as you would when on the bike putting tension on the wheel bearings. Those familiar crunching noises reappeared. It was the wheel bearings and not the bevel box! :juhuu:
When I had initially assembled the bearings and spacers in the hub I hadn't tightened the assembly far enough and had fitted too small a thickness spacer ring causing the taper roller bearings to be overtightened in the frame but not so far as to stop the wheel rotating. It was a straight forward job to fit a thicker spacer ring and give the correct tension to the bearings.
Thankfully it isn't always as bad as you first think - but the bike isn't finished yet and there is still plenty of time for me to make more mistakes and or learn more einzylinder mechanics. :schrauber:

Best wishes to all

:respekt:

Norrie

† Norrie


BenW

Norrie,

What a great story of overcoming the obstacles involved in restoring our bikes... ;)

"Our doubts are traitors,
and make us lose the good we oft might win,
by fearing to attempt."

― William Shakespeare, Measure for Measure

Cheers
BenW

Karl

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† Will

Hi Norrie, I know the feeling.
When I bought the R27 it would wheel forward all day long but not backwards. 2 of us pushing could not move it backwards, the front tyre just skidded on the ground.
When I took the wheel out and removed the hub cover I saw that the previous owner had not assembled the bearings and spacers correctly and the adjuster was sticking 4 mm out of the hub locking the wheel.
We need at least 3 machines.
One to ride, one to polish and one to spend lots of money on. At least my hydraulic workbench is earning it's place in the garage!  :)
R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

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