G: Gearbox (Twin) Cracked G4 final drive shaft

Bill Thomas

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I cut notches in mine many years ago, I think it came from Clev Trev , But not sure,
I was going too fast in third once, Wrong side of the road, Narrow road,
Overtaking too many cars and it locked up,
Lack of oil, My fault,
= 2 gears at the same time !!, Don't want to do that again,
I stayed on and didn't hit anything, Pure luck that day.
 

davidd

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Pat Manning had one split. He concluded that it was excessive wear of the Oilite bushing that caused the problem.

David
 

oexing

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What puzzles me is the trace of brass-like remains on the chamfer of the G 4. There should not be any chance for this except there was a lipped/tophat bush that crushed after hammering the chamfer. The remains of that lip could have been gone down with oil changes possibly. Anyone with ideas about these brass traces on chamfer ?
In any case I would not want more than 2 thou play bush- G 3 fit. Same with long bush in output shaft carrying the sprocket. Excessive play there will kill the output bearing by force of chain pull.

Vic
 

Bill Thomas

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I have seen sprockets that are a bit tight from new,
If knocked too much with a hammer, Could start to weaken it there,
You would be knocking those two things together,
Better to push the sprocket on with the nut ?.
As Greg says there should be a space between the two,
Without the clutch on, I like to feel the play by pulling and pushing the main shaft.
You should be able to hear the clearance.
 

oexing

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But the main shaft sits in a ball bearing tightly (hopefully) so you can only feel minimal play in the bearing ?

Vic
 

Bill Thomas

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But the main shaft sits in a ball bearing tightly (hopefully) so you can only feel minimal play in the bearing ?

Vic
The shaft the clutch is on , Is not a tight fit, In the bearing, Never has been,
Doing up the nut with the slots in , keeps it all together,
But if too loose, The thrust washer wears out,
That's why they say , Do it up to the next slot , never go back to the slot before.

If the bearing was a tight fit, It would be a begger to put together,
You would have a job to know if the alloy plate the bearings are in has gone all the way home,
Same with the layshaft bearing.
 

TouringGodet

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No modifications to G4.

Edit - well, no intentional modifications, ha ha

G4_1.JPG

G4_2.JPG

G4_3.JPG
 
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TouringGodet

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The Spares Co lists lead bronze and also Oilite bushings. Which is preferred for the G4?
 
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