Gearbox Layshaft Issue?

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When I brought my Norton new at the age of 17 I was a skinny 5'8" and 9 stone in weight as I got older and lots of beers my weight got to 115kg and now at soon to be 62 my weight is down to 88kg, never had any problems kicking my Norton from being a light weight to a heavy weight, sometimes our Norton's do some funny things for no reason at all and sometimes a compression lock happens, but not all the time for mine and a well set up Norton should be a one or 2 kick starter, depends on what ignition system you run and state of tune, but as the OP has said his locks up all time when kicking it, just trying to work out if its a problem with his Norton or the way he kicks it, gear box, clutch or kicking problem, did it do it before the gear box was rebuilt or after and how long the OP has owned his Norton might give some answers to why his does it and how much experience he has of Norton's.

Ashley
 
Had the Norton for almost 10 years. No issue with kicking before it was completely rebuilt -- inc. motor & gearbox -- and when it starts it runs like a top. The strange lock up did not happen for the first 2 months after rebuild and then it crept up and increased. I began to think that it had to do with the Boyer Mk3, so I replaced with a Pazon and still have the same problem. Thought it might be a little advanced, so I retarded a few degrees but to no effect.

My kickstart procedure remains just prior to TDC and then a swift motion through the kickstarter. Before rebuild and 2 months ago, it was a quick and easy procedure. We will see if the problem remains once I have shimmed & reassembled.

I am 170 lbs. Never had a problem before.

What do you associate with "compression lock"? It sounds exactly like this problem but I have not seen much about this issue elsewhere on the forum.
 
I am about the same size, shape, weight as you. I have always had to get a good strong kick into my nortons. 1/2 hearted kick never worked for me.

Your kick start mechanism looks in good order.

You mentioned when it "locks up", that it sounds like engaging a starter when the engine is running. That's a puzzle that needs looking into but can't think what it could be. Once the kick starter pawl is engaged in the first gear, everything is solid to the engine from then on apart from a slipping clutch type problem. I can only suggest you look at the clutch, and as others have pointed out, they recommend cleaning it out every so often, so no big deal. [ is this where that noise came from? ]

At least these machines are easy to work on. Making a clutch puller also is a piece of piss.

Dereck
 
I am at a lost in what could be happening but after you put the gear box back together and if it still does it I be looking at the clutch.

Ashley
 
Will do. Shims arriving this week - of course I got rid of my old shims when I went to Mk3 vernier isolastics.

To be continued.
 
Never bothered with shims on mine. Be careful that you do end up with the full overlaps of the kicker starter splines on the k.s shaft.
 
UPDATE: I disassembled the gearbox, inspecting everything, and reassembled with the proper play in the kickstart shaft. No change. The kickstarter still locks up near full compression -- even with the ignition off. The transmission is in neutral, and the rear wheel turns freely.

I took a couple of videos from both sides to illustrate the issue. The sound is more like a starter on an old auto that is already running. I suspect that there may be something amiss in the clutch, as Ashley pointed out. The motor turns absolutely freely and runs perfectly when started, but this issue has become progressively worse -- suggesting that there may be something wearing in the clutch assembly (new Norvil basket for belt drive w/Barnett plates), which I rebuilt along with the rest of the bike.

Any advice/ideas welcome:



 
nomadwarmachine said:
Primary belts are pretty floppy, to be sure. I can rotate at the slack point past 90degrees. What is the proper tension for these, and how could a loose belt cause this?
Click to expand...

IIRC the Norvil advice is that the belt should be able to turn 90 degrees only, not past that, so I’d agree it’s too slack. Norvil actually give really good advice on what the shaft centre distance should be for their different kits which takes away a lot of the guesswork.

It does sound to me like the noise we can hear in the video might just be the belt slackness being suddenly taken up and released?

Its a very easy thing to test for, just adjust the belt, and I’d deliberately adjust it too tight just for a quick experiment, it‘ll certainly rule it out or in.

BTW, certainly looks like you got healthy compression there sir !
 
nomadwarmachine said:
Primary belts are pretty floppy, to be sure. I can rotate at the slack point past 90degrees. What is the proper tension for these, and how could a loose belt cause this?
Click to expand...
with the belt to loose it will try to climb over the pulley and cause all sorts of trouble. i would set to about a 75 degree twist.
 
1) get rid of the dancing shoes, put on boots with a steel shank.

2) learn to kick a motorcycle by first ENGAGING THE PAWL, and THEN put your entire weight on it. Begin just after TDC, use the flywheel inertia (not your kick force) to get it through compression.
Your technique is all wrong. (Don’t be offended, this is nuts & bolts, not feelings.)
Gearbox Layshaft Issue?
 
Last edited:
Watching your second video again it seems to me that the noise you refer to is being caused by your clutch / mainshaft moving slightly after each kick...

And, sitting here with no norton to look at and refer to, all I can think of that can cause that is your kickstart ratchet mechanism...?
 
Torontonian said:
Get those spark plugs out.
Click to expand...
With the plugs grounded if a electronic ignition ?
Surely if it was some form of mechanical issue it would be there with the plugs removed, if not it is more likely technique. (or boosted compression as a long shot)
 
Time Warp said:
With the plugs grounded if a electronic ignition ?
Click to expand...
Or switched off ?!

It would be interesting to see a plugs out video and see if it’s any different.

Look at his second video y’all and look at what I mean about the clutch basket visibly ‘springing back’. That spring back is the noise I believe.

What’s causing the spring back ?
 
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