Clutch going? No it's much worse...

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Rusty bucket

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My clutch (or maybe not) felt as thought it had been slipping, with some surging it seemed. Made it off the road hearing metal grinding, turns out the chain is now off the rear sprocket and sucked in the primary... Game over ? Chain tension was fine. Old chain, Rusty brain on my behalf.
 
It's still on the trailer waiting to get sometime to cut the chain so I can roll it off and up on the lift. Anyone ever use big bolt cutters on a chain? It's pretty bound up in there and thought it might be easier than an angle grinder.

Worried it's bad bad bad... I'll report back and try and sort the picture thing out here with a membership to make it easier.
 
Buy yourself a chain snapper, you'll need it when you are fitting the new chain. It is one of those thingamies which clips onto the sideplates and you screw the handle to drive the pin out of the plates. Most bike shops should sell them.
 
We call it a chain breaker over here. It just pushes one of the pins out so the chain comes apart. The right tool for the job. The damage may not be all that bad. If the rear chain has wadded up around the countershaft sprocket it may have broken off the back shield part of the inner chaincase. A lot of people will just run it like this.

Just take your time with it when you are taking it apart.

Was just thinking, maybe you can just take out the master link if you're lucky.
 
I was lucky when the chain failed on one of the prototypes. It wound itself onto the track. Since I was doing just over 100 mph with the throttle wide open, the engine didn't fare very well - made a good boat anchor! We moved up from 1/4" chain to 3/8" pretty quick. Why they tried 1/4" I couldn't understand, as the 650SS and the Atlas had been using 3/8" for a long time.
 
frankdamp said:
I was lucky when the chain failed on one of the prototypes. It wound itself onto the track. Since I was doing just over 100 mph with the throttle wide open, the engine didn't fare very well - made a good boat anchor! We moved up from 1/4" chain to 3/8" pretty quick. Why they tried 1/4" I couldn't understand, as the 650SS and the Atlas had been using 3/8" for a long time.
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I can't understand that, lots of much more powerful bikes run 1/4 chain without issues, just look around any race paddock today...
 
Fast Eddie said:
frankdamp said:
I was lucky when the chain failed on one of the prototypes. It wound itself onto the track. Since I was doing just over 100 mph with the throttle wide open, the engine didn't fare very well - made a good boat anchor! We moved up from 1/4" chain to 3/8" pretty quick. Why they tried 1/4" I couldn't understand, as the 650SS and the Atlas had been using 3/8" for a long time.
Click to expand...

I can't understand that, lots of much more powerful bikes run 1/4 chain without issues, just look around any race paddock today...
Click to expand...

The metallurgy is way better now. It was probably a little ambitious to test it in 1967.
 
Rusty bucket said:
It's still on the trailer waiting to get sometime to cut the chain so I can roll it off and up on the lift. Anyone ever use big bolt cutters on a chain? It's pretty bound up in there and thought it might be easier than an angle grinder.
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Center stand intact? Drop the back wheel and let the chain hang off the swingarm while you position the bike. I would hope you would be able to gently extract the chain once you get the primary drive off. Trying to pull the chain out of there without some disassembly will probably chew things up all the more.

Follow link https://www.accessnorton.com/NortonCommando/technical-information.2265/ and go about two-thirds down the page for instructions on how to post images. It's not too much hassle; my doing it is proof of that!

Nathan
 
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Ah yes the chain is bound up behind the primary! Damnit! I need to order a replacement asap and sort this. Not looking forward to removing that stuff, I'm going to try and gently tap on a few areas with a punch and light baby ball peen, if no dice I guess I'm pulled stuff apart.

Any seals in there I should replace? primary gasket replaced with a new starter sprag, but still leaks a fair amount, maybe at he drain or fill plug.
 
Rusty bucket said:
Ah yes the chain is bound up behind the primary! Damnit! I need to order a replacement asap and sort this. Not looking forward to removing that stuff, I'm going to try and gently tap on a few areas with a punch and light baby ball peen, if no dice I guess I'm pulled stuff apart.

Any seals in there I should replace? primary gasket replaced with a new starter sprag, but still leaks a fair amount, maybe at he drain or fill plug.
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Rusty, Hard to tell from the post... just dreading a PITA job? or is this outside your mechanical comfort zone? Maybe you have a mechanic/millwright friend to help? Good luck :mrgreen:
 
You should be able to get it out with a little force, my chain did the same thing last year when it threw the master link and it wrapped around between the inner case and gearbox, but it wasn't a big job to get it out, a large screw driver tapping it with a hammer did the job, I now safety wire my master link, but this was the first time it ever done that in 40 years of owning my Norton, alway expect the unexpected, with any luck it hasn't done any damage to the inner case.

Ashley
 
Ashley, thanks for the advice. I was thinking that might work, lots of GENTLE tapping!

I'm not uncomfortable with wrenching just a bit tired of it! Seems like with all these bikes it's something, either expired tags, bad gas, gummy carbs or a small electrical gremlin. The other aspect is I'm not 100% comfortable with this bike yet. I hate the thought of getting in there and then needed parts thus leaving it open and sitting.

I'm going to try and work gently on this chain. A lift is very very for my busted back.

On the plus side my brother is coming home from Rio and we will be headed to Kennys shop in Jersey to check on the final stages of his built up Commando. Kenny seems like a hell of a nice guy and while we won't see him there we will be spending a little time at the shop and hopefully the adjacent shops as well. I should sort out my lack of photo posting and get some pics up of the bike. It's snowballed into a ground up bike and a rather slick looking ride if I say so myself. Started on the first kick from the video I was forwarded. Maybe Ken will post up pics of he build on his site in the future.
 
Maybe a change in ratio?

Is it me or are these MK3 geared excessively tall? I thought maybe it was poor carb performance with a single 34mm Mikuni but I'll be damned if first gear just seems too tall sometimes, feels like I'm slipping the clutch a bit to get it rolling without a chug and lug.

I may just pull that damn cover and get in this thing deeper on Xmas and replace that front cog, I hate to go more than a tooth at a time. any mk3 guys to a dive on ratios? Bike is bone stock and rather anemic IMO. Cruising speeds for me are low around 55-65. Don't need to pull the ton often!
 
Is it me or are these MK3 geared excessively tall?
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Rusty, yes, the MK3 has a 21 tooth countershaft sprocket, the front sprocket of your rear drive chain, and that makes it a bit doggy off the line.

By contrast, the Combat came stock with a 19 tooth sprocket, great for acceleration and also ease of redlining and whipping crank into bearing failures.

In your case assume your bike is still factor stock in that department and so after all these years that sprocket should be replaced anyway and why not with a nice 20 tooth

that will give you more spirit off the line, and yes the fact is that a single 34 Mikuni simply does not flow enough air to take advantage of your motor's abilities

consider installing new Amal Premiers and 20 tooth
 
My Mk 111 runs the 20 tooth with no first gear bogging down or clutch slip needed. Also no need to speed as the penalties here are severe after 120 kms. per hour if posted 100 kms. Max. 150 can be vehicle siezure ,not good.
 
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