N15CS Atlas bottom end

If you indeed do have a ball bearing and there is end-float, then the bearing is loose on the crankshaft or the bearing is loose in the the crankcase. You will soon find out. It is common nowadays to use roller bearings on both sides and shims to centre the crankshaft.

My engines didn't need shims but I am thinking I was just lucky.

The factory parts lists for Atlases and N15/G15s are badly illustrated. You are better off using Google (and other web sites) to find illustrations and also the Commando parts book has good engine part illustrations, not much help for the rest of the bike though.

You have not said which year your N15CS you have isas thereare four different parts books for the N15CS from 1963 to 1968. There is the Master Parts book for 1966-1967-1968, and the 1967-1968 with no illustrations. The 1964 N15, G15CS part book or the 1963 Atlas Scrambler one has the illustrations for the Dominator Featherbed models. You can use the illustrations for the wheels, gearbox, clutchand engine, and may be the front forks. The Atlas Scrambler had different fork internals. The only difference to the front forks,on the later bikes arelonger fork stantions andone inch longer dampers. The rest is from the AMC G12 range of bikes so the oil tank, tool box, petrol tank, frame, and the other cycle parts are from AMC. The petrol tank is the 2.2 gallon scrambler one from the AMC range of bikes. Use the Superblend main bearings, of the NJ306ETN or the later Commando ones, and fitthe 3/8 head bolts by the spark plug holes, and the later Commando flame ring head gasket if you have the earlier 5/16 head bolts.The 5/16 head bolts were notorious for blowing head gaskets.AMC or Norton Matchless Divisionnever ever published an illustrated parts book for the N15, G15, or the AJS 33, only a parts book with part numbers and some of those are in the wrong place and a washer part numberis really a nut. I have been looking for any factory illustrations since 1970, and I have only found illustrations, or picturesin the workshop manual. I have tried all over America and even Berliner never had any thing or so I was told.

This barrel and cylinder head can be up dated to the 3/8 bolts, by drilling out the cylinders heads to a larger size, and also getting the thread holes changed in the barrel. This can be done for you by any engineering company as I have had it done myself.The barrel can have the spigot machined off, and a spigot ring added, and the flame ring head gasket used. This is what Norton did in 1966 to their twin engines both the cylinder head castings and the barrel was also changed to effect these changes.Those parts books are available fromNorton dealers, and the one you require would be the green covered 1964 one, as this has your heavy front and rear mudguards, with the large dual seat, and scrambler front forks. The workshop manual the large A4 green Nortonone does have some G15, N15 pictures in it. There is also the Haynes Norton twin manual, as well as the American Clymer, and Chilton manuals that may still be available to buy. You may also want to add the smallhexagon stud that connects the rear of the chain case to the engine plate as this stops the chain case moving up and down. The chain case on the earlier models is onlyheld on by three screws on the drive side of the crankcases. The front forks have the G80CS damper internals and the fork springs spring are of the out side type that were changed to internal springs in 1966.

For the hex stud try Steve Surby of AMC Classic Spares and send him the part number as most of the G15, N15 series uses the AMC part numbers from 00, 01, 02, and the 03 number came out in 1967. The 03 number she does not have that many of. The earlier inner chain case does not have a hole drilled for the later hex studs location, so you will also have to do this and also add this hole to the rear engine plate.I did not import any Royal Enfield's only P11's and N15, and G15 models, but I nearly did import a RE Constalation back in the 1990's. but I bought a 1973 Triumph T100R Daytonainstead.I wrote an article about the first 200 Norton Atlas Scrambler's that were dispatched in October, November 1963, from 107388 to 107587 a few months ago and it was published in Roadholder. Your 1964 N15CS has many different features to the first 200 that were dispatched in 1963. There is also Russell Motors who can also supply these small parts for you. The spigot is the ring or the extension of the barrels liner and this fits into the cylinder heads small location in the combustion chamber. When this spigot ring is machined of these early cylinder heads, then the space has to be filled with a spigot ring infill. The 3/8 bolts torque is 30Ft lbsand the 5/8 bolts are torques to 20 Ft lbs. I did start to write and N15, G15, AJS 33 book but the P11 book sort of took over.

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