A Norton in a box

My friend has just brought a Norton Commando as a box of parts, the bottom end is all together and frame together with wheels and front end, it looks like a late 750 but one thing that has got me is there is no breather coming from the back of the timing case and it has no breather from the end of the cam where most of the 750s came out, it has a disc front end, F/G tank painted black with gold pinstripes, my friend wasn't home when we looked at its so didn't want to poke around to much.

Here got it for $4,100 which is cheap for a Norton here in Aus. but needs a lot of work, bores have no lip, gear box is all apart but the gear box parts are there and the head looks good, gear box shell and motor bottem end is in the frame with new rear guard, wheel have SS spokes, the seat has the dot patten, next time I go see it I will take pics and post them here.

Ashley

ashman said:

it looks like a late 750 but one thing that has got me is there is no breather coming from the back of the timing case and it has no breather from the end of the cam where most of the 750s came out

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A late ('72 - '73, 200000-on) 750 would normally have the "rear crankcase" breather [46 - 53] :
http://www.nortonmotors.de/ANIL/Norton% ... 04&Part=46

Might want to get the numbers off the cases when you take photos.

You didnt say what colour it was .

Perhaps there is an easy way to restore this basket case to it's former glory ? There was a Three Stooges comedy in which they were working on the engine of a '40 model Mercury. Mo said 'quick the owner is coming', so they look a big shovel and scooped up all the engine parts which were laying on the floor and tipped them into the engine bay, and slammed the bonnet. They then got into the car turned the key and it started.
Might have been this one :

https://www.youtube.com/watch?v=J96zfbwijMs

I've always remembered this and have used the technique extensively when building my Seeley 850. I use a cement mixer to rebuild my gearboxes, you just chuck in all the bits, turn it on for a while, and then tip out a nice new fully rebuilt gearbox.

Black with gold pinstrips :roll:

Well I found the breather, it is at the back of the crank case half way up and inbetween the engine mounts, I have never seen this on a Norton motor, but have taken a few pics










Ashley

Yep and the real Nortoneers tell me they can remove and install Combat baffler or other breather devices in there w/o moving engine or gearbox, just not me is all. LAB says not all cases like that were Combat spec engines above their cranks but not as like as it being a real Combat Bomb shell I love the most. Heck if not a Combat likely still been run till crashed and taken away from us.

The engine number is 2212.. in the box of parts it has a set of 750 pistons as well as a set of 850 flat top pistons, my friend Mark is a mercant seaman and is only home for a few weeks at a time, I have been given the task of rebuilding the gear box and motor while he is away at sea, he will supply all the parts needed.

I am retiring from work in 2 weeks time, my job of 31 years has been made redunded and have been given a very good redundancy pay out as well I can get my Super to retire at 55 years of age, so this project is the begining of my new life restoring a few Nortons in my early retirment.

Here is some more pics of Marks new Norton





This is all I got as my battery went flat.

Ashley

Breather down low between support plates is normal. Combat-style. Better to evacuate crankpressure pulses quicker than previous attempts.

ashman said:

The engine number is 2212..

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22xxxx makes it a 750 MkV so roughly speaking it's a 1973 model, the breather is as it should be for a '72 -'73 750.

Thanks LAB, I had a idea it was, I will have another look today and see if the head is a Combat head, it has 32mm carbie manifolds, he has a few more parts to pick up from the former owner and thats where the carbies are.

I can't wait to get the motor up on the bench, the head and barrels are just sitting on the cases, the pistons are off the rods, but the bottom end hasn't been touched yet, so will be intresting to see if the main bearing have been changed, it has just over 24,000 miles on the clock, but the speedo and taco are in bad shape and needs full rebuild.

This is going to be a intresting project and can't wait to get started.

Ashley

ashman said:

Thanks LAB, I had a idea it was, I will have another look today and see if the head is a Combat head, it has 32mm carbie manifolds, he has a few more parts to pick up from the former owner and thats where the carbies are.

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The presence of that type breather should not in itself be regarded as an indication of it being a Combat model, it's just that some people can't manage to mention that breather without adding the "Combat" part. :roll:

A 750 MkV 32mm head should be either RH5 or RH6.

True,some person here.

Thanks again LAB, I will check the head out and I had a idea it was a 73 model with the disc brake, I don't think the bike has been on the road for sometime.

Ashley

Based on the serial number, the black clutch handle mount, and the long black speedo mount, it should be a Mk V 750 (1973) and the head should be stamped RH6 (high compression) or RH5 (low compression), not a "C".

Thanks Ron, it is a 73 and not a combat, I will get the motor and gear box tomorrow to start on the project, Mark has another week off before he goes back to sea for 6 weeks, he's getting the gear box bearings tomorow and I will get anything else it needs for it to be put together and while he is away I will pull the bottom end down and see what is needed for that and make a list of parts that will be needed for the rebuild.

Ashley

ashman said:

it is a 73 and not a combat

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I have a 235XxX MKV 750 original. 30mm carbs and head is unstamped. Inlet port measures 28.5mm (about).

Never seen a MKV 750 with original 32 carbs. Check inlet port size on the head to see if you have the matching manifolds.

Cheers

Mark

I keep these bearings on hand if it helps.

http://norcomcycles.com/Gearbox.html

Well its been sometime since i got this motor and gear box, the gear box is now fully rebuilt, I started on it first and all the bits were there but had to replace the sprocket, all the bushes where in new condition with no wear at all, the bearing were stuffed from sitting so long, all gears are in great condition but had some rust on the sharfs, have replaced all bearings and roller laysharf bearing, the gearbox went together without any problems.

I pulled to bottom end down as the head and barrels were all ready removed as well as the pistons, had troubles removing the pinion gear but with the right puller on it came off, once the cases where split the main roller bearings were in good shape and will be reused, no marks on the bearings at all, the rods then were removed and the slipper bearings were in good condition with just a slite wear mark on the drive side bearing, have replace the rod bearings and they are standard bearing, there was no wear marks on the crank at all so this motor has not done to many miles, but one thing I did find was a broken ring sitting on the bottom of the crank case in a bit of sluge, but there was no damage at all to the bottom end so I am hoping the ring was broken when they pulled the barrels off and if fell into the bottom end and stuck to the drain plug magnet.

The bottom end is going back together now, the bores in the cylinders have rust marks where the pistons and rings sat with out moving, so this motor has sat for sometime, one piston had a broken ring, but what we did fine was one bottom compression ring is jammed tight in the ring skirt and can't even move it, this piston has signs of running hot, but the other piston is OK, the plan now is to get 20+ oversize pistons and a rebore, I didn't get the chance to see the head as its gone to another person for the head work to start.

My friend wants me to fully restore this bike but I just don't have the room for another bike in my shed till I extend it so for now its just the motor and gearbox on the bench with a box full of other parts.

Ashley