Norton Commando kickstart & gearbox query?

[headfullofsnakes]

Hey I have a problem maybe someone can give me some advice on...

I have a MKII 850 Commando and when I accelerate away from a complete stop the kickstarter pulls itself down. It comes back up almost straight away, and doesn't do it again when changing through the gears.

I have just completely rebuilt the gearbox and it's all good, all the bearings are sweet etc.

Also it only does it when it gets nice and hot. So after a good 20/30 minutes riding.

A bit lost as to what to do next!?

[FJRider]

I had an old Honda with the same issue ... the kick-start return spring ... had not been set with enough tension.

Or it's lost its tension strength ...

[Voltaire]

I too have a Norton Commando and would reccommend you go to Access Norton forum, The guys on there know lots about Nortons.

[headfullofsnakes]

Cool thanks for that, will check out the spring and will try the Access Norton blog. Didn't know about that.
Cheers,
HFoS

[Grumph]

The layshaft pilots in the kickstarter shaft so when you release the clutch on takeoff you're loading the kickstarter shaft which then turns.
Was the bush inside the kickstarter shaft renewed ? - It may be a tad tight.
Alternatively yes, the return spring may not be installed correctly.

[Dodgyiti]

The Access Norton; Commando Forum is pretty good. Whenever I have a question I search it on there and someone has always asked it before:yes:
Hopefully it is the return spring, it will be a hassle if the shaft is a bit tight:facepalm:

Or Blast from the Past group on KB has an ongoing thread 'Norton Natter' you'll learn nothing there:laugh:

[Voltaire]

Or Blast from the Past group on KB has an ongoing thread 'Norton Natter' you'll learn nothing there:laugh:

Mainly its just some former Westie banging on about the perceived coolness of Moto Guzzis with double pumpers........:innocent:...and more lately fuel economy... :killingme:

[ntst8]

The original layshaft bearing has a name for not being up to the task, and can result in that symptom when it is on its way out. Hopefully not the case if you are happy with the bearings but worst case it can lock up the gearbox if it fails.
On the other hand i had a similar symptom on an older style Norton gearbox and it turned out just to be a weak return spring.

[headfullofsnakes]

I ordered a new spring and pulled the old one out yesterday. I haven't ridden it yet with the new one in, but I can tell already that it ain't the problem. I couldn't perceive any difference between my old spring and the new one!

Looked on Access Norton and yeah there's a similar problem comes up a couple of times. They always say the same thing; bearing or bush... or the shaft itself. A friend put the shaft on a lathe for me when we had it apart and said it was only about two thou out, which he thought was fine. But the fact it's only doing when it's hot surely means it is a clearance issue eh???

[Paul in NZ]

I ordered a new spring and pulled the old one out yesterday. I haven't ridden it yet with the new one in, but I can tell already that it ain't the problem. I couldn't perceive any difference between my old spring and the new one!

Looked on Access Norton and yeah there's a similar problem comes up a couple of times. They always say the same thing; bearing or bush... or the shaft itself. A friend put the shaft on a lathe for me when we had it apart and said it was only about two thou out, which he thought was fine. But the fact it's only doing when it's hot surely means it is a clearance issue eh???

Yeah maybe but its the whole box that heats up.

Um - I'm mr Anally retentive about this stuff but if it was me I'd pull the box and go through it super carefully with a special look for cracking around mainshaft and layshaft bearing / bush holes. With the few norton and more amc boxes I've done in the past I like to assemble them with just the shafts and make sure the spin OK as I had a terrible job with an AJS box because the layshaft bush wasnt in square.....

Point is - with the Commandos extra stomp (and make no mistake a good combat 750 can honk) the old Norton box was getting to its limits in that chassis and they can lock up and very bad things can happen...

One things for sure...

these guys

http://www.norvilmotorcycle.co.uk/

WILL know and they do a gearbox rebuild 'kit' cheap as chips....

[Dodgyiti]

That's a good link thanks Paul:niceone:
I thought Norvil sold only the kits to make Norvils but 129 Squid for the full AMC reco kit including the springs is pretty good value.
I would have to spend a bit of time adding up the parts from the British Spares catalogue to be sure though. Everything seems cheap for these Nortons, and more importantly...avaliable. Once you cough up the initial purchase price for one it is not too scary keeping them on the road.

[Paul in NZ]

Norvil can build anything up to a brand new commando in various guises. Once the trademark / brand issues were sorted there was no stopping them.

I think the way they have produced those 'kits' is brilliant and for the gearbox its well worth doing it right.

A decent Norton would be one bike I'd swap the Guzzi for but I've ridden some horrors. My mates old combat is the one I should have purchased, I've never ridden another that had so much stomp apart from my modified Atlas but it was ridiculously and stupidly hotted up by a punk kid with too many dreams and too little cash (me) so it didnt stay together very long..... sigh...... (fun while it lasted though) Funnily enough, it was a lot faster in the corners when I fitted the std Atlas engine bits after the big blow. so much easier to ride.

[Voltaire]

I've had my Combat for a few months and I'd agree that they can " honk". They spin out quickly.
Mine needs a new clutch as its not releasing cleanly....winter jobby.

[Grumph]

back to the original query....no one's mentioned oil yet.

Some of the modern gearbox oils don't work particularly well with bronze bushes.
What are you using ?
As previously asked, was the bush in the center of the kickstart shaft replaced ?

[headfullofsnakes]

Using Castrol EPX 80-90.

But there was a time, briefly when I first got the bike, that I had an HP oil in it I think?

No the bush in the center of the kickstart shaft wasn't replaced. Will try that next?

[Grumph]

One other possibility which came to mind is the case gaskets.
If it had gaskets originally between the case and the sandwich piece, and you've simply used RTV or similar - as people do, not condemming - then the layshaft is going further into the kickstart shaft which means it's running on a small area of unworn bush. This could well account for your symptoms.

[Redmoggy]

Once fitted, make sure the bush is reamed to size or you could have the same problem.

Roy