MKII (a?) basket case

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Jan 1, 2009
Hi from Brooklyn NY,
I'm 38, work as a graphic designer (for now) in Manhattan.
I'm new to bikes (last year I rebuilt a 76 Honda 550), but I have been wrenching on things all my life. Years ago I had a 67 Impala SS, that I still pine for. I have always loved Nortons, and finally got one.

I bought a 74 850 commando basket case,
frame/case number 312365,
I think this means it's a MkIIa, made in March 1974.

Supposedly it was hammered by the PO until it threw a rod bearing, he then bought a 75, and when it broke down, he salvaged parts from the 74 and sold the left-overs to a bike shop in NY, where I got it.

It's been powder coated, and had some fixes and new parts, so I thought of it as a project on the uphill,

but it's also missing quite a lot, and I didn't take it apart,
so I'm still in the reading phase, puzzling over parts lists and one big pile of bolts and bits.
I hope to put together a parts order next week, and with luck it will start to take shape in February,

Hopefully I'll be able to add some pics as it comes together, here are a few of it fresh out of the basket,

MKII (a?) basket case

MKII (a?) basket case

MKII (a?) basket case

The Emgo pistons came with the bike, I'm pretty sure I should get new Hepolites, but does anyone have experience with these?

MKII (a?) basket case

MKII (a?) basket case

MKII (a?) basket case

MKII (a?) basket case

MKII (a?) basket case

The last pic is the interior of the cases, I was told that the rod bearing dug into the case and that it was repaired. My first concern is that the cases are now missaligned, because the camshaft does not turn freely. If i could afford it I would send the engine to CNW, but that might jhave to wait till next year.

Does anyone know a place on the east coast that can sort out the cases?

This year I just want to get it together and running, to see what it's like. I spent $2.5k on it, and I figure to spend another $2k this year in parts. Then $4-8k over the next couple of years. Hopefully I can get a rough looking but semi-dependable (no oil issues) ride together by summers end.

thanks for all the great posts,
noco said:
I bought a 74 850 commando basket case,
frame/case number 312365,
I think this means it's a MkIIa, made in March 1974.

Welcome Noco,

I think could just as easily be a MkII model?

The II and IIA models were produced alongside each other, as the MkII models primarily went to the USA, and the noise emission MkIIAs to UK/Europe during the early part of 1974 at least.

If it's an "A" model it would have had the large Black plastic airbox and the bean can/Black cap silencers/mufflers?

The photo shows the carb is stamped "R35", which is the MkII R/H carb number, and the MkII L/H carb should be L36?.

The IIAs had R33 and L34 carbs.
$8K to get to a nice endpoint is probably a realistic goal.

looks like a fun project. make sure to post lots of pix along the way, and detail your ups & downs.

The Emgo pistons are good quality, they are made in Tiawan and the Triumph version is used by racers, only the rings are suspect so go for Hepolite rings. On the camshaft it sounds like the repair of the bearing was a welding job which has distorted the cases, if so more than the camshaft may be out of true eg the deck for the barrel may now have a lip on the joint, best have someone used to Norton cases check it out. Another possibility is the cam may be out of another engine, it was on an engine I got in bits and one of the camshaft journals was plus on the OD, a simple grinding job back to spec sorted it out.
L.A.B. said:
I think could just as easily be a MkII model?

thanks for pointing out the difference between MkII and MkIIa,

I've been sorting through the bits for a while and feel like the bike is stock and unmolested, so I think the carb numbers define it as a MkII.
kommando said:
only the rings are suspect so go for Hepolite rings

so I could order a set of rings (.20 over) from Hemmings and put them on the emgo pistons?

It would be a relief to save a couple hundred bucks at the moment,
especially because the top end seems easier to revisit than the crank cases,
and I'm starting to think the cases will need a lot of work ,or a replacement, I'm looking at it now and the deck is definitely uneven,

I'm going to put in a call to memphis motor werks (thanks JimC),
I also plan on bending Phil Radford's ear,

thanks to all
You have matching frame and case numbers at the moment, this is important to some people if you ever consider selling later on but no point in retaining them if they are too expensive to fix. Hepolite rings are avaialble from Mick I believe.
When you posted, "I'm looking at it now and the deck is definitely uneven", I said someone slipped you a Micky. Sounds like one half of the crankcase was damaged beyond repair and replaced. As far as I know, that's a definite no-no. Leo can tell you what you need to do. If I had the money and needed new cases, this is where I'd go:

I don't mean to dissuade you, but Norton's are not cheap bikes to restore. If you aren't prepared for five figures, stop now. One that has parts missing and need crankcases may go well over $15,000. A CNW bike, someone posted here, goes for $23,000, plus a donor bike. Take a look at one and figure out what you will sacrifice for your resto. Add up the costs of what you skip and subtract from that $23,000 figure and you'll be close.
JimC said:
Sounds like one half of the crankcase was damaged beyond repair and replaced.

The two crankcase halves would normally have been stamped at the factory with identical numbers at the lower rear of each case, to show they are a matching pair, so it should be easy enough to check if the cases are mis-matched or not.
hi noco before you send the cases off anywhere try this,loosely assemble crankcases and bolt the barrels on tight , makeing sure the mating surfaces are clean and there is no high spots,then tighten crankcase bolts and see if the cam turns more freely, same thing can be done to see if the crank turns freely, check the cam for straightness, it could be that the cam bushes need line reaming, this is best done with the barrels bolted on too,also check bushes for any imperfections and cam journals too,if you do need to get another set of cases you could re stamp them with your original numbers, i dont think brand new cases come with an engine number so you would have to do it to new ones, hope it doesnt come to that though good luck and keep us posted
chris plant said:
loosely assemble crankcases and bolt the barrels on tight

I am going to try this today,
also, have a look at the camshaft,
try to id it, check the OD,
and see if the case numbers match,

Is there any way to remove the timing gear/camshaft, without the crank in the cases?

The manual says the to do this properly, you have to use the crank as a lever to get the nut off the camshaft gear, but my crank/timing pinion is out. I can't think of a way without messing up the cases. I'm guessing I'll have to put the crank in, to get the camshaft out.

this is how the case is now
MKII (a?) basket case
wanted to give an update,

i got the nut off the camshaft gear with an air impact wrench, so never mind the previous question...

the cases do have matching numbers stamped on the bottom of the drive and timing side, "569", so I don't have mismatched cases

I did not try bolting the cylinders on the cases to see if it freed up the camshaft, (is this done so that the cylinders are used to align them before the case bolts are tightened?)
I'm working on the bike at a shop in Brooklyn run by some experienced triumph racers, and the guy I was working with wanted to try some other things first,

Mostly we tested the camshaft in either bushing and looked for tight spots, the end result seemed to be that the drive side bushing is the sticking point, and should be line reamed,

however there is still some question about whether a welding repair to the drive side case (thrown rod bearing) warped it. Just running my finger over the loosely assembled cases I could feel a lip on the deck.

My buddy had me apply valve grinding compound on the case lips, and then rotate them together to smooth out the mating surface, and look for problem points ( I think a flat grey color is what your going for and shiny spots point to trouble),
there were some noticeable shiny spots,
after several applications there was one shiny spot that corresponded with the area that looks like it was spot welded/repaired
(heres a pic) it's a little hard to see, but the bolt hole in the foreground is shiny with a dull grey color above it (which I guess is what you want the mating surface to look like after you finish this) just below it are some dark grey blobs that I think are the evidence of repair

MKII (a?) basket case

heres a pic of the camshaft, I'm not sure how to id it, it didn't have a number on it, but I have a feeling it's stock

MKII (a?) basket case

Obviously I didn't find all the answers I set out to, but I feel more confident that it can be resolved with line reaming the bushings and close attention to the case lips, (after several applications of valve grinding paste there seemed to be a good amount of uniform gray color), still have to figure out if the crank is miss-aligned and whether the deck miss-alignment can be fixed by skimming
I am going to give it some more attention this weekend and if I find out anything interesting I will let you know,

ps: does anyone know what this number is? It is on the inside of the timing side case.

MKII (a?) basket case
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