G15CSR

[bell]

Would it need to be dis-inclined to fit ? , anyone tried it . regards Richard

[itma]

I would be dis-inclined to try

[bell]

"why" , regards Richard

[John Donne]

When the Atlas engine was fitted into the G12CSR frame to build the G15 series the drive side of the engine was machined to take the large spacer, and three extra screw holes were added for the alloy AMC primary chaincases, to be fitted. The stock Atlas only has the three holes for the press steel chaincase. The earlier Commandos or Atlas Mark 3 as the then Norton Villers or Matchless then first called it, has a different timing cover - the one with the revcounter drive - to the standard Atlas. Even though they look the same, the difference is the hole where the pressure relief valve is located, and also the part number would be different. This i found out when i bought one of those covers for one of my N15, G15 models. The balance factor for the crank of the Commando would also have to be change to 84% as the Commando is rubber mounted, and the G15 is solidly mounted in the frame. The Commando i think has a balance factor of 57%. The G12 frame was also altered to accomadate the Atlas motor, as the front frame mounting lugs were changed to fit the engine. The timing cover would then have to be changed for the stock Atlas one, as the motor would now be fitted in an up right position in the G15 frame. As small point but vital for your oiling if you did not know about it. Make sure the bearing are the NJ306ETN type or the Superblend ones.

[itma]

plus you would need the Commando gearbox and clutch.
Commandos were famous for destroying gearboxes.
The AMC clutch is not up to the output of the Commando engine which is a lot more than the Atlas.

[John Donne]

If you fit a belt drive then this would not the be a problem, as the clutch would handle the power. There is also a gearbox conversion that that is made by Seve Maney called a Gearbox Outrigger, if you are running the longer mainshaft. This longer mainshaft always gave problems when the Commando was raced, hence the Steve Maney fix. This was £95 for the outrigger, and £14.98 for the sealed bearing. There is also the Quaife reinforced gearbox shell, that would also help.
That is if any one wanted to do this conversion. Just get a G15 set of crankcases, and put the correct type of motor in the G15 frame, so then there would not been any problems.

[33CSR]

John,

A few years ago the Spares Scheme had a few original rear brake pedals for G15 + Model 33 CSRs - I have one fitted to my 65 33 CSR on an improvised pivot arrangement. It may be worth a call as I doubt the demand has been great.

Good luck - the parts search for these models is always challenging!!

Regards

Roger

[John Donne]

I shall ask Mike Partridge of Walridge Motors in Canada,when those G15CSR rearset type rear brake pedals are going to be fabricated, and who will be making them. My own 33CSR does not have the earlier rearset brake pedal, but the later street srambler type rearbrake pedal. My 33CSR was fitted with the CS type rear sub frame. I only found out when i counted the holes on the rear sub frame assembly This may be an option if you can not find that brake pedal. I was also told that the G15CSR rear brake pedal was a converted AJS 7R one. Russell Motors used to have them and may still have them in stock. AMC added an extra block of metal to the side so the brake pedal stopped at the footrest. The brake pedal spindle i think came from Domiracer, or Accessory Mart in Cinccinate. You may be able to imput the part number on their web site or send them and email, as they may have it in stock, plus the other footrest parts that you require. A large amount of G15CSR's were exported to North America going by the factory dispacth records, so North America may be a place to look for the those rear brake parts. Some of the those parts would have come from other models in the AMC range, as the footrest look very much like the pillion footrest fitted to other AMC model twins and singles. Some of those footrest came painted in blue, as well as sump guard clips, so i suspect the factory fitted these to their G50CSR, or as the factory called it a G50CS.

[GOLDSTAR]

John your information on the early commando/atlas engine is very informative and welcome, I have a very early commando no 127748 I'm told about 1500th made this has the atlas engine and very little information about this 'change over' model can be found thank you. kind regards

[John Donne]

The first Commando's or Atlas Mark 3's started at engine & frame number, 126125, so that would be a simple subtraction. Norton Villiers issued, silver sales brochure of 3 types, plus a workshop manual, and a hand book. All these i have original copies of. There was a lot of factory issued written literature issued from Plumstead at that time. I found my workshop manual at Kempton Park, on the Don Mitchel stall. I thought that it would be very funky to have it. I also have a collection of those factory handbooks, that covers that earlier Commando. There is also the Haynes manual, the American Chilton, and Clymer publications. Those earlier Commando's are now highly prized, and sought after, so it is a shame you do not have the whole bike. Try to get a set of G15, or N15 crankcases, as they are readily available in North America. That engine does have many different modifications to the other Atlas engines made at that time. The earlier series of the Commando stopped at 128646 or 10 to 20 before that number, as the next numbers were for the P11A Ranger 750's. A large amount of the earlier Commando's were dispatched to Berliner in Hasbrouck Heights, New Jersey, USA.