Norton N15CS Hybrid restoration

A forum buddy asked me to take on a special project for him, which I gladly accepted; it is a somewhat rare
Norton N15CS "hybrid" using an Atlas 750 engine in an AMC frame. Similar hybrids were built in various
conglomerations and branded AJS & Matchless.

This bike is in great shape and my buddy even rode it a couple of years back, nothing much happened to the bike
in between that last ride and last February when he brought it to me at the Roebling Road race track in
Georgia. It is mostly complete, with some of the bits & bobs handed over in various boxes.

As this is a non-typical restoration project, most of the owner involvment will be "behind the scenes" as far as this
forum is concerned. Some of the details are going to be excruciatingly difficult to get exactly right, and some may
never be 100% verifiable; this IS a hybrid, and as such could prove impossible to authenticate due to the fact
that the original documentation for specific bikes from specific dealers may never be found. Furthermore, a few
of the items will be modern replacements (tires, spark plugs, hoses), so perfection is impossible.

Nevertheless, we're going to strive to achieve as near a re-creation of the '67 N15 as is possible given that the
available pile of cash might actually be declared limited at some point!

With that, here is the starting point:

I just got the "Notice To Proceed", as the funding has finally been secured.

For what it's worth, the fenders and original carbs & manifolds are all in a box, not to worry!

Wow,

Am I going to be watching this one or what? My first real bike was a G15CSR, so pretty similar to this.
I did see a few of the hybrids at the Clubman show in San Jose last weekend and talked to a few Norton guys who had them. Somebody had a very similar model to this for sale.

Yep, sombody else I know saw the same bike and was considering it...

I did see one with the same tank and color as my old bike, but it had the full valanced fenders, kind of the touring model.
I would have a real personal struggle if I saw a real CSR for sale that I could afford.
On the other hand I get happier with the featherbed every day. With the new carbs and ignition I'd say it is about twice as smooth running as before at low speeds and far easier starting.
Where did the bike you are restoring come from? Was it an old racer?

I don' know the history of the bike, the client "had it out back for years"...

Paul, I hope you'll be posting photos of the restoration as it goes along. There are plenty of photos of Commando restorations, but not so much o these less ubiquitous models.

Yes, this is the start of the typical project thread.

Teardown starts Tuesday or Weds.

Dave and I are probably some of the biggest hybrid fans here.
I recently found an old Peter Williams article that said the G15CSR was the worst racer they had ever given him. Gee, it did OK for me but I'm sure I wasn't riding it to the level he was!

Cookie, with our strange penchant for hybrid Nortons and Chang Jiang 750s, we must have been twins separated at birth! Notwithstanding the occasional negative reports one reads about the various hybrid models, these are in my opinion some of the most elegant looking bikes of their era and could arguable be described as the 'Super Motards' of their day - not the best for sustained high speed work, but ideal for blasting through traffic and medium speed riding with a good turn of acceleration. I'm hoping that a decent dynamic crank balancing job will render my N15 project rideable without shaking all the fillings out of my teeth.

I'm noticing a lot less vibration since switching carbs and ignition on the old featherbed. I'm not sure how they balanced her when it was rebuilt but I think it will be far more livable this year.
Previously it would walk away at an idle and now it sits there and goes poom poom poom.
I didn't think the G15CSR I had was all that bad for vibration and if you do a good balance job on your engine it should be not much worse than a Bonnie I'd think.
Back when I had the CSR it beat everything I met until the Honda 750 four I raced. By then she must have had 50 drag races on her and the engine was noticeably weaker. I missed a shift against the Honda and never got a fair go at him again as I blew her up a week later.
It is true she was no featherbed in a corner and the closest anybody came to me was a guy called Al Wagner with a modified Bonnie. As soon as the GSR started to chatter with the back wheel you had best let up or she was going to go around. Oddly enough she didn't do that on gravel roads and controllable slides were easy.
The Italians always make exotic bikes that are rarely seen that would have been faster about 1966, but I never saw one, and until the Honda four those hybrids took some beating.
I also think many of them were among the most beautiful bikes ever built, but hey, I'm prejudiced.

Paul, How is progress going with your project, Any chance of some photos?

One thing led to another, and i haven't started yet.

Soon, lads, soon...

Hi Hybrid fans,
I grown so fond of them I'm selling my commando to buy a '67 Matchless G15 cs I've managed to track down. I think they're the coolest looking bike ever! Anyway a couple of questions. First of all, in the period american ads, the G15s usually have no silencers fitted. Would removeing the silencers to the bike i'm buying be detrimental to the engine? Secondly, should i use a monograde oil, say a 40 or 50? Any help/info would be much appreciated.

If you rejetted the engine no. Plan on your neighbors killing you though, perhaps increase your life insurance. Most of those bikes were run in the desert like that and few cactus complained.
Monograde was all that was availabe when I have my G15 CSR, these days I like something I can kick over in the winter too.

...Inquiring minds want to know...Have you started the resto?

Yeah,

I was going to check to see if we should send your wife condolences.

No condolences, no progress.

Sorry.

It was a LONG 5 week contract, working 50+ hours a week at 100% from daybreak almost 'till dark every day and dealing with 105+ temps unloading & reloading trucks and unpacking / re-packing computers.

I need a vacation!

The last time I did that was when I started up the SFO combined shuttle program. Thank God for Coke and pizza delivery.

Well, a few of you lads might be happy to know that progress has begun in earnest.

The bike on the lift with all the bits bolted on to form a complete "before" picture-


This is what the client is wanting to arrive at his driveway in about a year's time-


I almost NEVER use other people's photos in any way, shape, or form, ESPECIALLY without permission,
but I've tried to track this photo's owner down and came up empty. As far as I know, the '66 & '67 N15CS
were the same except for concentric carbs on the very latest ones.