Twin Gearbox questions


Well Known and Active Forum User
VOC Member
Hi all,
I´ve just opened the box on my D shadow as it constantly jumped out of first gear under load (increasingly less load as the problem increased).
On inspection of G9 & G10, the dogs in G10 are completely rounded off, whilst the dogs on G9 show chamfering on the drive side of the dogs.

From what i have been able to find in the books, drive in first gear appears so:
1.) Clutch carrier (C3/2) drives the clutch mainshaft G3
2.) Constant mesh pinion G6 is keyed to G3 and drives the constant mesh gear G7 which is splined to the layshaft G5
3.) G10 is also splined to the layshaft G5 and with 1st engaged, G9 is pushed into G10 and G10 drives G9 over the engagement dogs
4.) G9 drives the large gear on G11, G11 being splined to the final drive shaft G4 = drive to the gearbox sprocket.

Am i correct in my asumptions here?

I think what is happening when first jumps out is, as soon as load is applied to G9 through G10, the worn dogs are causing G9 to be pushed back out of engagement. Is this plausible?

On further inspection of the various components, i have also found:

1.) I have a lot of play between the large bush G16 in the final drive shaft G4 & the clutch main shaft G3. How much axial movement should be present here? Can i find measurements anywhere?
2.) I can rock the camplate on the camplate spindle. How much axial movement is allowed between the camshaft spindle and the camplate bevel?

I would appreciate any help anybody can offer me here. I have read every vincent book i have, but can not find tolerences or measurements relating to gearbox shafts/bushes or the camplate spindle etc.



Well Known and Active Forum User
VOC Member
You will probably find that it has never been in first gear, ever. Assemble the box, put it in first gear, take out the spring and detent, look to see if the notch in the camplate is central with the hole. If not, that tells you that the bevel gear is against the stop pin in the case, and will not allow the camplate to rotate to it`s nesting position. Usually caused by the bevel gear in the camplate being badly machine. PM for answers.