Hi all
Any observations appreciated.

Coming back from Arnhem on the M20, found I could not find neutral, changing down slowly from top to bottom first gear a bit clunky, but would not go into neutral even at slow speed coming to a stop, managed to jiggle it into neutral by hand.

Unable to get neutral at standstill, lot of jiggling by hand would find it.

Changing up through gears no problem, changing down to second no problem, first a bit metalic and clunky.

Clutch not slipping, pulling ok at 45 to 50 on main roads.

Stripped clutch at home bit grunge about but not a lot, all fibre discs measure 3/32 thickness, no wear apparent, fibre discs are the type with flecks of brass.

Cleared up all metal discs and baskets of burrs.

Assembled clutch leaving out one fibre and metal disc just in case it had been dragging, tightend up clutch nut using brass drift on last turns, bike would not even kick over because of clutch slip!

Reassembled with missed out disc and plate, bike kicked over ok, no slip.

When the clutch plates and discs are held together in the hand they measure 1" 1/32 in total thickness

Will give bike a run out tomorrow to test gear change?

Any observations appreciated.

John B
North Yorkshire

The M20 box can get 'notchy' and stiff to operate when the oil level is too low...Have you checked that?...

The oil level can drop to excessively low levels in just a few hundred miles if no sealed bearing is fitted...Ian

Thanks Ian
Will check that in the morning.

John b
North Yorkshire

Neutral tends to hide behind a dragging clutch. you'll have to start looking for it!

John there must be something wrong if your clutch slips with the two plates removed. 3/32" is the correct thickness for new plates. (I have seen after market plates that are thicker). I'm far from alone who run all the time with two plates removed. My M20 is running a 600cc engine and My V twin Indian/BSA special is also running with the same set up. Neither bike slips. Apart from the much more comfortable lighter clutch, It also gives more room in the clutch basket for the plates to separate and help stop drag......Which in turn should make it easier to find neutral Ron

email (option): ronpier@talk21.com

I agree with Rons comments regarding clutch slip....

Also check that you have sufficient free play at the clutch operating arm, the cable is free, lubricated and routed correctly and that the clutch operating arm is set correctly to give maximum lift...

It should be vertical when the handle bar lever is pulled in fully...

There is a lengthy piece in the 'technical section of the website ref. clutch slip/drag/setting up....Ian

Hi Ian and Ron

I was wondering the same about the removal of a fibre disc and a metal plate, in that it would make the clutch easier to operate and give more room in the basket.

As I mentioned the thickness of the whole amount of fibre and metal discs when held in my hand and measured is 1" 1/32", does this give any indication where things a possibly going wrong.

When putting the clutch together and tightening the spring I use a spanner then a brass drift to really tighten it.

The clutch rod rotates whilst in place and the operating rod ball bearing just say touching, when the clutch lever is pulled in, the operating arm is in the vertical.

I've ridden the bike a short distance on the drive, am able to get neutral when coasting to a stop, also able to get neutral at stand still.

Will take bike for test run tomorrow.

I noticed that while the bike is stood still on tick over, if I touch the gear change lever slightly, just a small movement upwards I get a grating noise as though part of the selector mechanism is hitting the gear box dive shaft somewhere, could a spring be gone in the selector or is that normal.

Ian I topped up the gearbox oil as well!


Any advice before taking clutch off again and gearbox

John B

North Yorkshire

John I got your email and here is your clutch for any scrutiny.
I have never measured a full stack of plates. But if you add up 7x18G and 8x3/32" it does indeed come out at about 1 3/32".
It makes me wonder if your clutch main spring is buggered. It should be very difficult to assemble a clutch without some sort of compression tool.
The free length of your spring should be 2 3/8" and condemned at 2 1/8"and should require a pressure of 240/250 lbs to compress it to 1 1/8" condemned at 215 lbs. Ron

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email (option): ronpier@talk21.com

Hi Ron

I used a compression tool to get the spring started, I think the spring was the right length, but could dismantle and check.

Is there a difference between the Cush drive spring and the clutch spring, could a cush drive spring have been put on instead of a clutch one.

As I mentioned after cleaning up the clutch basket and plates that has improved thingas a lot.

I have noticed that there is very weak spring resistance against the gear lever ( in comparison to my other bike) you only have to touch the gear leaver slightly upwards and a grating noise happens.

Is it possible that one of the clutch selector springs has bust and that is part of the problem as well.

Out comes the gearbox today!!!

Those awkward bolts on the rear of the outer cover, is there any off the shelf bolts to put in that can be taken out in situ?

Oh happy days

John B

The shock absorber spring and the clutch spring are a different diameter as well as a different length...

Check that the clutch pushrod slides easily in and out of the mainshaft, they can get tight with rust or have restricted movement if bent...

You should have 'free play' between the clutch pushrod adjustment screw ball and the pushrod, not a running contact, so that there is no chance of them not separating fully when the clutch handlebar lever is released....

Check this free play at the pushrod end, not the handlebar lever end...

Wear in the bronze handle bar lever pivot holes can give a false impression of how much free play there actually is at the other end......

You can fit studs into the outer gearbox cover which means you only have to undo the nuts to release the cover. However, it is harder to get the nuts back on afterwards...

Personally I prefer, and use, bolts for this reason...It is much easier to get the bolts in and out if you remove the outer (return) oil pipe first...

This isn't too messy as there is little oil in the return pipe and the contents of the tank won't drain out when it is removed...Ian

....You can fit studs into the outer gearbox cover which means you only have to undo the nuts to release the cover. However, it is harder to get the nuts back on afterwards...
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For that reason I reduce the studs over a short distance, enough to let the nuts slide over them. Then it is easy to engage the thread...

email (option): viaconsu [at] planet [dot] nl

Good idea Hans...Though wouldn't you have to have slightly longer studs to maintain full thread engagement?...

The thread of the studs or bolts into the cover is 1/4" Whitworth by the way...Ian