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My Norton is taking shape

oldGSfan

Forum Sage
Past Site Supporter
This 66 N15CS was a pile of parts when I got it. It's been an archeology project to figure out what's missing and how it all hangs together, because this bike has a strange pedigree and no frame and body diagrams are available. It's frame is Matchless, as found on G12 and others, with a Norton Atlas 750 engine, Roadholder forks, and the normal Lucas electrics and Amal carbs as seen on the UBMs.

As I put it together like a puzzle, it's turned out to be in very good shape and is mostly complete. The oil and fuel tanks were custom painted by a local sign painter and it's hand lettered and striped. I like it but it's not original. I'll continue the theme of making it look and run great but not try to make it original. I have a disc front off a Commando to replace the drum, for instance.

I just put the swingarm together and Right now I have some old Suzuki GS850 shocks on it as they are about the same length and fit the bike for rolling around. Front yoke (triple tree) and fork rebuild coming up next, as I also tackle the engine and gearbox, full teardowns.

It has a single VM34 Mikuni and 7.6:1 compression pistons, so it's not a firebreather, but should be very tractable and fun.

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Cylinders .040 over and decked to remove spigots, as I have a better non-spigoted head (a protruding ridge to locate cylinder head which really is not needed so Norton ditched it).

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Time to paint the barrels and get all the correct studs and nuts etc. Crankshaft is still being reground, it's been a 3 month wait!

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I made an engine stand from plywood, I ain't paying $100 for some fancy schmancy metal one!

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Footpeg mount is odd, is from a 1946 design or maybe even earlier. Square locating rod is positively located by the transmission mount plates, but the pegs themselves are not! Seems they would have locked the pegs in place as well with a square hole in each side's bracket. Weighs a ton.


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Pushing in the swingarm 'pin' with some all thread and sockets/tubes.

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The centerstand spring will be interesting to get on. I think someone bodged it up with a curved loop to help find it with your foot, but then it appears a hunk is cut out of it. Again, no diagrams whatsoever to show me, just some Matchless YouTube videos I've found. I need a side stand, but people are asking as much for one as I paid for the whole bike (150)

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Great to follow along, Tom.
Like the engine stand.

Not staying original, aren't there repro side stands out there?
Redoing a CB77, complete original side stands are in the $500.00 range. I found reproductions bits for less than half.
 
That looks like a really fun project! Keep going...
 
Thanks Steve, it just came to me to stop looking for Norton (which always seems to have a markup...thanks Keanu!) and check Matchless, AJS, etc. as many Britbike parts are shared. I found one which may be right for only 63$ on eBay, repro from India. It even shows measurements so I will check if it's right. I bet it is.


Great to follow along, Tom.
Like the engine stand.

Not staying original, aren't there repro side stands out there?
Redoing a CB77, complete original side stands are in the $500.00 range. I found reproductions bits for less than half.
 
Thanks Ed it sure is. I'm just finishing up restoring the inside of my '69 Airstream Caravel, so now some time will free up. That took a few months as I basically gutted it. Maybe I will flood the zone with some pics of that, after all this is the 'other projects' section.

That looks like a really fun project! Keep going...
 
Beautiful. Leo Goff was getting his street P11 into the 11s back in the 70s and 80s. That is basically your bike but with the Chrome Moly Matchless G80CS frame. Nortons fast and reliable compared to the BSA Triumph and AJS/Matchless twins.

I had this Atlas in the 70s up to the 90s. I did commute on it, and toured it as as far as a 1500 mile week. Never rode one with a Matchless frame. The Atlas shook a lot.

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I have received most of the parts I need to refresh it all, not cutting corners. Lots of research on fasteners. I have the barrels .040 over with NOS oversize low comp pistons, the crank is ground and I am ready to take on the engine and the front suspension and brakes. New stanchions, fork rebuild kit, and going to a disc brake from a Commando - not terribly strong but beats a drum. I figured it's not going to be stock with that paint and seat, and I got a great deal on the disc setup.

I lost 2.5 months after the parts arrived March 1 as I had to travel north to take care of my ailing dad (RIP). It was quite the ordeal and I'm mentally and physically worn out, but the Norton will provide a welcome diversion. I'll post pics when I get to the nitty gritty.
 
This is the build I've been waiting for since you first showed us the beautiful body parts more than a year ago!

How is Mister T?
 
This is the build I've been waiting for since you first showed us the beautiful body parts more than a year ago!

How is Mister T?

Well, life got in the way and I am finally back home, doing OK considering. Top tip: plan for your eventual demise and don't hoard stuff. What a mess.

The bike is going to be really nice, it had 10K on the clock and by the innards I can tell it's correct. For instance, inside the two piece crank is a 'sludge trap' that was quite clean - I've seen some teardowns online with huge globs of sludge in there. The transmission is really good but I'm replacing bushings and bearings anyway. Those old AMC gearboxes are very robust and smooth shifting. Today I mounted the new shocks and I like the ones I got, no shrouds. I hate shock shrouds for some reason and the rear needed some chrome. I also scrupulously cleaned the fork lowers and will assemble them tomorrow, will post pics as I go along. There are some great tips on making the big twin relatively non-leaky that I'm reading up on.
 
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Here's a pic of the Long Roadholder forks ready to assemble with new springs, stanchions, lowers from Commando with disc brake mount. Bushings and seals were a kit, not terribly expensive. The stanchions are about an inch longer and the mudguard has a bit more clearance for off-roading as compared to Atlas & Commando of that era. I need to decide what tires to mount, it would look cool with something a bit dual purpose but I may just go with tried and trusted Avon Roadholders. I've been seeing modded UJMs with full knobbies, all I can say is wow.

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Crankshaft is bolted back together, with fresh regrind it looks great, too bad it's hidden!

I also put the rockers in, finishing that job, the spindles were in very good shape, all looking good. It's a little tricky putting them in with a spring, they are a press fit so I heated the head to 200F in the BBQ and lightly drifted them in, making sure the oil passage holes to the tappets are oriented correctly.

The crankshaft halves will come together with the proper 'superblend' bearings and I will need. I have made a few of my own tools, the MacGyver is strong in me.. My valve spring compressor is a real hack with a C clamp and a cut spark plug socket :rolleyes:

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That $10 spring compressor is awesome, I love stuff like that.

Well it was all free sorta since it was in the garage. It was about 1mm from not working out. There are several Norton specific tools I might have bought but made using stuff on hand. The right tool makes things easier but what fun is that?
 
Forks rebuilt with new bushings, seals, stanchions and damper parts. It's using stock internals, there are damping and other improvements that can be made but we'll see how it goes. I fitted the lower leg from a Commando with the disc brake. The internals on the N15CS are different and stanchions are longer, but the lowers are the same dimensions thankfully.

I found an inexpensive and very nice Yamaha Vino scooter master cylinder. It has the 1/2" bore that helps the ratio. Norton MCs are pricey and they sleeve them, but 10x the cost. This will work fine and I didn't even need to rebuild it.

Waiting on a new top nut for the yoke, the one I have is 26 TPI and they changed to 28 TPI on the Commando yoke I got for it. Mine was missing and I had a really rare 63 Royal Enfield Interceptor one that wouldn't work - I sold that for more than I got the whole bike for.


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Looking good Tom. It's also good to see your old GS's are still with you. :)
 
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