Gearbox work

RoT · Nov 23, 2004

ok I was having a bit of trouble with 2nd gear slapping during deacceleration so ive decided to take a crack at dismantling the gearbox from my mkII 850 commando. I removed the gearbox outer and inner covers according to the manual without any dramas, and I can see clearly that the 2nd gear cog has lost 2 adjacent teeth. It doesnt look like it has caused any other damage. Before I go any further I need a bit of advice. To actually remove this gear(or gear set) is it necessary to dismantle the clutch and stator etc, I am on a low budget and cannot afford to buy pullers or other specialised tools. Does the whole mainshaft have to come out to replace this cog? Any workarounds, tips or advice welcome thanks.

nortonfan · Nov 23, 2004

no special tools required, just a bit of common sense.

When i pull mine apart, I lay the top set(mainshaft) all in order on my work bench, so they go back in the same way.
The bottom set of gears (layshaft) i lay in order also but to the right hand side of the others.

the two forks inside are held in position by the rod that is threaded into the chaincase side of the case. the "forks" are easy to remove but need a bit of a "fiddle" to get back into position on reassembly.

If u had the workshop manual all would be revealed for reassembly as u do have to have the gearbox "camplate in a certain position etc.
If I can pull one apart & put one back together & it works....anyone can.

hope this helps.

Anonymous · Nov 23, 2004

nortonfan said:
no special tools required, just a bit of common sense.

When i pull mine apart, I lay the top set(mainshaft) all in order on my work bench, so they go back in the same way.
The bottom set of gears (layshaft) i lay in order also but to the right hand side of the others.

the two forks inside are held in position by the rod that is threaded into the chaincase side of the case. the "forks" are easy to remove but need a bit of a "fiddle" to get back into position on reassembly.

If u had the workshop manual all would be revealed for reassembly as u do have to have the gearbox "camplate in a certain position etc.
If I can pull one apart & put one back together & it works....anyone can.

hope this helps.

so you dont have to dismantle the primary and clutch to get them out?
just remove the forks

nortonfan · Nov 23, 2004

If u r only replacing the 2nd gear, u don't have to touch the primary.
Once u have a bit of a look inside, it is a piece of cake.
U will see.

RoT · Nov 23, 2004

nortonfan said:
If u r only replacing the 2nd gear, u don't have to touch the primary.
Once u have a bit of a look inside, it is a piece of cake.
U will see.

cool, thanks

Anonymous · Nov 24, 2004

RoT,
If you have gone this far you may want to check the layshaft bearing located in the far side of the shell case. This is the weakest point in the teransmission. If it is a single row ball bearing replace it now or else wait for it to explode sooner then later.
Ride On
Dave

norbsa48503 · Nov 24, 2004

The first gear bushings and the layshaft bearing update are "got to do" when your in there. Poping off the clutch to put in a fresh circlip behind it is also minimal requirment for a well used beast. I always buy three clips at a time and never reuse them. norbsa

Gearbox work

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nortonfan

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