Author Topic: gear selection or not  (Read 2742 times)

Offline spyke

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gear selection or not
« on: 07.03. 2010 21:37 »
Hi chaps,

Just come in from the garage a bit deflated (again), thought I was going to get to gearbox in bike today and only ended up with gearbox still clamped in vice!
Have rebuilt gearbox with new bushes, bearings,springs etc all reamed and just so. Gears ,shafts,forks all look serviceable.Timing dots lined up.
Fitted inner cover and tightened screw then used a screwdriver to move quadrant up and down and managed to select all gears and neutral up and down.
So finally fitted outer cover with selector mech and gear lever etc. now selection seems a bit iffy ,ok going one way but then a bit queer coming back the other.
Are the two pointy ends of the selector fork/plate (67-3341) critical, mine appear to be a bit "blunt" . As do the castellations on the end of the quadrant(67-3347) although I hope this isnt buggered as I dont think its available any more.
Comments or any other ideas very welcome .

Cheers Spyke
A10 spitfire style

Offline muskrat

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Re: gear selection or not
« Reply #1 on: 08.03. 2010 08:41 »
G'day Spyke,
                  "iffy and queer" sure your on the right forum ? LOL.
Those parts should be nice and square, they do round off with wear. Also wear in the quadrant pivot and teeth that engage the cam plate can give problems.
Is the spindle free or is it stiff. The new bushes may have cramped it up. To check loosen the outer case screws and nuts 1 turn and try again.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Rusty nuts

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Re: gear selection or not
« Reply #2 on: 08.03. 2010 09:12 »
Spyke

I've had this problem on plunger boxes.
It's easy to mix up thrust washers the layshaft one should be 0.093" thick the kickstart ratchet one is skinnier 0.07something" I think.
Layshaft washer 67-3203 should go between layshaft 1'st & 3rd gear not placed on the end of the shaft up against bearing.
This is not obvious looking at exploded views.
Of the three boxes I've done two had this in the wrong place.

It sometimes helps to jiggle the mainshaft when testing selection on the bench.
If you get good selection but becomes "iffy" when all bolted up try removing the inner gasket.
If this helps bolt it up without gasket just a thin smear of blue hylomar, assuming faces are good should not leak.
Or you may have to go the otherway & increase gasket thickness though this is unusal & would indicate further end float issues in which case you'll have to try different size thrust washers.

Hope this helps.

Rusty
1949 A7 Plunger
1947 A7 Rigid Star Twin
1969 Triumph T120R
1972 Triumph T120V

Offline spyke

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Re: gear selection or not
« Reply #3 on: 08.03. 2010 20:23 »
Ive tried loosening off the cover nuts a fraction and checked the thrust washer positions and thicknesses, no diff .Again with the gearchange mech in and gear lever on ,but cover NOT ON, gears seem to be able to be selected ok but put cover on even without tightening or even having any screws in at all and gears are iffy again.
I wiped a bit of paint on the gear box cover inside and tried selecting again then took mech out and it has paint on top and bottom.So it seems to me that maybe the mech is not quite being able to travel just enough distance to come up or down the gears as it strikes the alloy of the cover.
The areas  where its hitting is machined flat like its meant to be a stop ,is it? and do you think its worth grinding off a few thou with me dremmel to allow that bit of extra movement.
Cheers Puzzled Spyke
A10 spitfire style

Offline muskrat

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Re: gear selection or not
« Reply #4 on: 08.03. 2010 20:58 »
G'day Spyke,
                  Been quite a while since I've been inside my box and don't know if it's possible. Can you dis-assemble the selector spindle, turn 180 deg and re-assemble to see if it makes any difference.
For me I find gear box probs are more frustrating than engine rebuilds, but usually a silly error on assembly.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline flashblack

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Re: gear selection or not
« Reply #5 on: 09.03. 2010 19:44 »
Hi, if you get stuck, i have a few g/box spares including outer cover, i could bring over to try on yours, to see if you can figure out what is happening. Should be able to suss it out between us.
  all the best Rich.
build it, ride it, live it!

Offline spyke

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Re: gear selection or not
« Reply #6 on: 09.03. 2010 19:53 »
cheers mate very much appreciated

Spyke
A10 spitfire style

Offline trevinoz

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Re: gear selection or not
« Reply #7 on: 09.03. 2010 22:02 »
Spyke,
             The timing dots can be a problem as sometimes they are not quite lined up when the quadrant is in the correct position.
With your outer cover off, select the gears from 1 to 4.
In 1st , there is about 1/8" clearance between the top of the quadrant and the aperture in the inner cover.
In 4th it is around 1/4".
When you are selecting the gears with the box fully assembled, are you turning the mainshaft as you do so?
This usually helps with the gear change.
There is a possibility that you are one tooth out with the quadrant to camplate.
I have done that and although 4 gears could be selected, it was a hit and miss affair.
Trev.

Offline Josh Cox

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Re: gear selection or not
« Reply #8 on: 12.03. 2010 08:53 »
Have had a couple of issues with my plunger box that I believe I have worked through.

1) Neutral was hard to select.
2) When changing back from third to second, sometimes it would require two lifts of the gear selector for the gear change   ( first out of third, second into second).

Adjusted the cam plunger in two turns, and rode it, neutral was now easily selected.

Adjusted the cam plunger a further two turns in, and have just been out riding and both issues now appear resolved.

Any thoughts ?, is it really that easy ?.
Black 1953 Golden Flash Plunger

Online orabanda

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Re: gear selection or not
« Reply #9 on: 12.03. 2010 09:21 »
Yep!

Offline Josh Cox

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Re: gear selection or not
« Reply #10 on: 12.03. 2010 10:15 »
Orabanda,

You may be happy to know the magnet in the bottom of my gear box is clean and staying that way, thank god.

I've fixed my horn, a slight adjustment, said the Bishop to the Actress.

Is the Minister in town ?, did he let you kiss his ring ?.
Black 1953 Golden Flash Plunger

Online orabanda

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Re: gear selection or not
« Reply #11 on: 12.03. 2010 11:34 »
He is here, and has just performed benediction!

Offline Josh Cox

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Re: gear selection or not
« Reply #12 on: 12.03. 2010 11:53 »
Can you ask him to help me, I am an agnostic dyslexic, in search of the one true dog....... *smile*
Black 1953 Golden Flash Plunger

Offline muskrat

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Re: gear selection or not
« Reply #13 on: 12.03. 2010 14:19 »
i'm starting to worry about U 2.

Spyke, how's it looking, any progress ?
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline spyke

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Re: gear selection or not
« Reply #14 on: 12.03. 2010 15:42 »
Nope
A10 spitfire style