Gear selection on Mk111

Joined
Mar 6, 2007
Messages
87
Hiya
I need some advice please with my MK111's gear slection problems.

It jumps outta 1st when pulling off from a stand still and it will also jump back into first when coasting to a stop after selecting neutral. This invariably happens just after I've selected neutral and let out the clutch, at very low speed. This is done as neutral CAN be very difficult to slect from standstill, but not alway, sometimes it'll slip right in..
A wee bit of background to the bike. I got it probably less that two years ago and had to recomission as the previous owner had it rebuild by Norman White of Andover, rode it less than 100 miles then left it in his garage. That was twenty years ago.
So after a few months work and upgrades it was running beautifully but the gearbox has never been smooth.
I've put probably a couple of thousand miles on the clock since, no more than that.
Among the receipts I got with the bike was the list of parts and work supplied by Norman White. It was a very comprehensive rebuild including stripping and checking over the box. There are three bearings marked as new on the receipt as follows.

L J 1 ½ 2Z
NF203 C3
L J 5/8
Can anyone tell from these numbers if they are gearbox bearings?

I have the bike up on the bench and the box stripped stripped out with the shell still in situe. The layshaft bearing has definately been replaced with a roller type and my next job is to mount the layshft betweeen centres and check for true, but as it was already done proffesionaly I'm not expecting anything untoward there.
Also supplied and fitted by Mr White were the Primary chain, Rear sprocket and clutch cable. Can't think of anything alse relevant on his list that might contribute to this problem.
I have also replaced the springs inside the gearbox cover and set the ratchet spring (a coupla times) as per the intructions to the point where I'm happy it's correct.
I stripped out the clutch plates and cleaned them up, adjusted the clutch a coupla times but all to no avail.
I've had a look at the camplate and it doesn't feel loose in it's bush but intend removing anyway just to check, along with the quadrant. Also I'll check the camplate plunger to ensure it's not worn flat and the spring length is correct.
I really want to get to the bottom of this before spring as it's ruining an otherwise smashin ride, but am at a loss. I thought about sending it off for a proffessional rebuild would prefer to experience the learning curve so I can sort it myself next time.
Any help and suggestions greatly appreciated in advance.
thanks
millard
 
Joined
May 19, 2006
Messages
1,612
Country flag
It sounds as if you're checking all the right things. Clutch drag is the usual cause of poor neutral selection but shouldn't make it jump out in use. A clutchless change doesn't do that.

An over-engaged neutral lamp switch on the Mk111 can also make things a bit sticky.

Is there any wear / damage on the dogs from first gear ? Was the mainshaft nut tight ? I'm assuming that the quadrant was indexed correctly and not coming up against the aperture in the inner case before selection was complete ?

Have you thought about giving Norman White a ring or taking the box to him for a look ? He's very approachable. I've seen him building boxes and he has a cut-away case for checking engagement so I would be surprised if there was a fundamental problem.

I'm sure that you don't need to go to the extent of paying someone to rebuild the box. It's not a complicated thing and it sounds as if you have a good idea what you're doing.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,759
Country flag
Hello Millard,

(So you finally made it!).

millard said:
It jumps outta 1st when pulling off from a stand still

Yes I've had the same thing happen, and I think this is probably due to a combination of camplate under-selection caused by clutch/gearbox drag from cold gear/primary oil, and/or the clutch not correctly adjusted, and also the left foot versions' gear selection is not as direct as the right foot models, a build-up of slop in the cross-over shaft components resulting in some loss of direct mechanical input to the ratchet mechanism.
This problem only seems to occur on my own MkIII after the first start up and first selection of the day, when the clutch has spun off any excess oil from the plates after pulling away it no longer jumps out of first gear.
Selecting neutral at a standstill can also be a problem at times so I normally find it easier to select neutral before coming completely to a stop, although I've not had the box jump back to first as far as I can remember, but again I would think this is due to the selector mechanism not fully selecting neutral and the camplate rolling back to the previous gear.

Are the bronze plates still fitted? As a change to the more modern fibre plate kits can improve clutch operation. I am still using the bronze plates but I think I will change them this year.


millard said:
L J 1 ½ 2Z
NF203 C3
L J 5/8
Can anyone tell from these numbers if they are gearbox bearings?

The bearing info appears to be incomplete/wrong but suggests they are the gearbox ball/roller bearings.


millard said:
The layshaft bearing has definately been replaced with a roller type

If you mean the drive side one (there is a needle bearing conversion available to replace the T/S layshaft plain bearing) then I would normally expect the 850 MkIII to have had the roller layshaft bearing when it left the factory.
 
Joined
Nov 10, 2006
Messages
1,370
Country flag
Hi Millard,
Check the selector fork, if its bent or sloppy it might give the symtoms you describe.

Hi LAB,
I've worked on a couple of Mk3 boxes and they were all fitted with a ball race, out of interest, when did Norton start fitting the roller?
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,759
Country flag
cash said:
Hi LAB,
I've worked on a couple of Mk3 boxes and they were all fitted with a ball race, out of interest, when did Norton start fitting the roller?

Cash,
I don't have any actual production number when the roller was fitted from, and I must admit I've always thought (from the general info available) that the roller bearing was fitted from somewhere around the start of '75 production? Although as you have pointed out this may not actually have been the case (apologies to Millard, as the original bearing could have been a ball after all?).

The roller bearing now generally supplied by Norton has the same part number as the 1975 parts book bearing (067710) the 040100 (earlier ball bearing part) listed as a "maker's or superseded part number" alongside it.

The MkIII factory manual also lists the layshaft bearing as a ball bearing, but again I have always assumed that this was another technical oversight (one of many) maybe many early MkIIIs did have the layshaft ball bearing?
I have a vague recollection of seeing a production number printed somewhere(?) a long while ago regarding the layshaft bearing change, and if I find out any more detailed info then I will post it up.
 
Joined
Mar 6, 2007
Messages
87
Hiya.
Thanks for your replies.

79x100 I'm taking your advice and going down to see Norman White Friday morning with everything but the shell which is still in the frame.

An over-engaged neutral lamp switch on the Mk111 can also make things a bit sticky.

Once I got inside it all I realised that the reason the neutral light doesn't work is that the plunger isn't making enough contact so I doubt if that's a cause.

Is there any wear / damage on the dogs from first gear ? Was the mainshaft nut tight ? I'm assuming that the quadrant was indexed correctly and not coming up against the aperture in the inner case before selection was complete ?

Dogs look OK to me but I'll take Norman's advice on it.
Mainshaft nut was tight.
Quadrant was indexed OK.


(So you finally made it!).

Yeah I was a bit slow off the mark Les, sorting other bikes which took my eye off the ball wi the Commando for a while.


clutch/gearbox drag from cold gear/primary oil

it happens hot or cold


but again I would think this is due to the selector mechanism not fully selecting neutral and the camplate rolling back to the previous gear

I suspect your on the right track here Les. Hopefully just a question of narrowing it down.

Are the bronze plates still fitted?

Yeah, but might not be after tomorrow's visit to Norman.


then I would normally expect the 850 MkIII to have had the roller layshaft bearing when it left the factory.

Wasn't aware of that, I thought they were all balls :)
But then I'm new to Commandos and still on the bottom few rungs of the curve

Check the selector fork, if its bent or sloppy it might give the symtoms you describe.

Had a look at the camplate and quadrant bushes tonight Cash and they're nice and snug.

I'm hopeful that with Norman's input tomorrow I should be able to reassemble over the weekend with the probs put to bed.
I'll let you know how it goes.
Thanks for your advice and any more ideas would be gratefully received.
cheers
millard
 
Joined
Mar 6, 2007
Messages
87
we must have posted about the same time Les. Mine was posted just as your second reply was in the pipeline, so thanks for the clarrification on me balls :)

millard
 
Joined
Dec 22, 2006
Messages
6,650
Country flag
My MKIII jumped out of gear when I first got it. It had quite severe clutch drag when cold and neutral was hard to find. It would usually jump out of 1st for the first and second startoffs and would stay in gear from then on.
On the clutch drag problem, someone told me to switch to ATF in the primary, the idea being that the thinner ATF would reduce clutch drag.

I emptied the primary and filled it with Mercon ATF. It reduced the clutch drag a little bit. The bike continued to jump out of first when cold, and neutral was still hard to find.

A member of the local Norton club informed me that Mercon ATF was not ideal, better to use the type F. He said that for some reason the Type F ATF cleans the plates up and just makes the Norton clutch work much better. I switched to the Type F and after using the bike a bit, the clutch drag disappeared. That was several thousand miles ago and I have not had the bike jump out of gear a single time since the clutch drag disappeared due to the Type F.
I guess the clutch drag was preventing 1st gear from fully engaging.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,759
Country flag
worntorn said:
On the clutch drag problem, someone told me to switch to ATF in the primary, the idea being that the thinner ATF would reduce clutch drag.

I did the opposite, going from ATF back to engine oil (as others had recommended elsewhere) because it was said that ATF didn't allow the hydraulic MkIII primary tensioner to work correctly, and after changing over there was certainly less primary chain snatch at low speeds/revs and the primary also seemed to run more quietly.
I didn't notice any difference in the clutch action though.
 
Joined
Dec 17, 2005
Messages
24
Country flag
Hi !

I used to have problems with my gearbox jumping out of 1:st gear!
The problem grew worse over time and was a real pain.The solution in my case,was an advice from a "oracle", that made me feel for axialplay on the kickstarteraxle, and if there was excessive play,he adviced me to shim it down.
I fabricated a washer of correct dimensions and fitted it between the kickstarteraxle and the lower gearboxaxle reducing play to a minimum.This tightened up the stacking and made 1:st gear engage in a better way.
The problem with jumping out of 1:st was history,..... and still is,twenty years later!!
My bike is a -72 Interstate, maybe the same cure applies to a Mk 3 Commando!??

Benton
 
Joined
Nov 10, 2006
Messages
1,370
Country flag
I'd put my money on the end float, I'd forgot I had to shim on my own Mk3 12 years ago.

The clutch drag is most likely to be caused by gear oil seeping along the clutch pushrod. Fit a seal and you'll have a no problem finding neutral or have any clutch slip. Norvil sell Dyno Dave's seal.
Another solution might be stop the gear oil getting into the mainshaft drilling in the first place. Perhaps, fit a LJ 5/8 ZZ and remove the inner shield.The clutch actuation mechanism would need packing with grease to replace the lost oil supply.
I'm going to try it one day.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,759
Country flag
cash said:
The clutch drag is most likely to be caused by gear oil seeping along the clutch pushrod. Fit a seal and you'll have a no problem finding neutral or have any clutch slip. Norvil sell Dyno Dave's seal.

I fitted the Norvil pushrod seal, and I didn't notice any difference in clutch operation (no easier neutral selection etc.) although I would agree that the conversion is probably a good idea.
 
Joined
Mar 6, 2007
Messages
87
I took all the innards and the clutch and primary drive components complete, except the shell to Norman White yesterday.
He pronounced everything in good order and was initially at a loss as to why it should be jumping in and out of gear. Until I mentioned that neutral was difficult to find sometimes. "Only two reasons for that" says he, “first is clutch drag and the second is the neutral switch wound in too tight"
And when he looked at the cam plate there was the evidence. The dimple on the rear which engages with the switch plunger had a grove worn in it because the switch was too tight on it. Norman ground it off and it should be fine now.

A couple of questions I raised with him during the course of the hour he spent inspecting things.

Primary oil, Norman reckons to use 120cc of 10w or 20w fork oil topped up with a little engine oil as it's not a very good lubricant.

In all the time he's been working with Commandos (I think he said 38 years) he's only had to shim 6 boxes due to layshaft end play.

He can't remember if the MK111's were fitted with ball or roller races on the layshafts.

He reckons the bronze plates are fine and doesn't see the need for any other type.

I'm taking the bike back to him sometime over the next coupla weeks so he can adjust the isolastics for me. I've never been happy with the vibration and he reckons that not only is the manual incorrect in how to adjust them, but most people don't know how to do it properly anyway.

It was interesting to hear Norman chatting about rear Commando hubs. His casual remark along the lines of "I'm embarrassed to say that I was responsible for that being adopted" was like a direct link back to Norton Villiers all those years ago and very poignant.

All in all he spent about an hour with me and I didn't think about it until later, but he didn't charge for his time and all I bought was a couple of new gaskets. He even talked me out of buying a new swinging arm and bushes as he reckons they should be OK and correct isolastic adjustment will take care of the slop at the rear end.
I'm going to pay him for that hour when I return and in future if I need parts he'll be my first port of call.

I'll be throwing it all back together over the weekend so I'll let you know how it goes.
Thanks for all your suggestions.
millard
 
Joined
Nov 10, 2006
Messages
1,370
Country flag
The bronze plates do last forever, however, once you get a completely dry clutch they do snatch a little, well mine did. I found the snatching was a bit of a pain as my Mk3 is well over geared. Since fitting Surflex plates I haven't had a problem, and the slight increase in stack thickness has given me a girls clutch.

LAB,
It's strange you are still getting clutch drag after preventing gear oil contamination.

Next time you have the clutch apart degrease the plates and check they are flat. I think another cause could be the loss of pushrod movement if the clutch gear box lever isn't kept at the bottom of its stroke while setting the clutch up.
Cash
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,759
Country flag
cash said:
LAB,
It's strange you are still getting clutch drag after preventing gear oil contamination.
Cash,

Yes that is a little strange and I cannot be 100% sure that it actually is clutch plate drag as with the engine not running, in gear with the clutch lever pulled there appears to be no clutch drag whatsoever.

Possibly this drag is not coming from the plates but maybe elsewhere in the gearbox? I have thought maybe oil drag between the sleeve gear bushes and mainshaft could possibly be the actual cause? Once underway this slight drag coupled with the initial 1st gear selection problem disappears.

Millard,

Regarding the neutral switch adjustment causing the neutral selection problem (as with T160s etc.) I would think that over-adjustment could cause bad neutral selection regardless of whether the engine was actuallly running or not? Is that what you have experienced? As with my own MkIII with the engine not running the box will easily select neutral and my switch is only screwed far enough in so that it only just works, once the engine is running neutral becomes more difficult to select when the bike isn't moving.
 
Joined
Mar 6, 2007
Messages
87
update

Well just to let you all know that it appears to have been the neutral switch causing the problems.
I finally got it all reassembled today, for the umpteenth time (don't ask) and went out for a short run. The difference is dramatic to say the least. It selects 1st celanly from standstill and no longer jumps outta gear on take off, also it no longer jumps back into gear when rolling to a halt after selecting neutral.
On the whole it's VERY much improved.
Thanks to you all for your suggestions, specially the one about taking the box to Norman White :).
cheers
millard
 
Top