What to do next?

I'm expecting my frame and assorted bits back from the powder coaters soon and I'm trying to figure out how to proceed with the build. I'm trying to figure out whether to install the engine as is and try to get it running to check it out or whether to gut up and tear it down and rebuild it before it goes in the frame. I'm doing a frame up build. Engine is a late 72. Norton owners club says it should have superblends based on seriel number. Clock shows 12,000 miles. Sump was full of oil and engine seems to turn smoothly with good compression. Bike wasn't super rusty, so I don't believe it sat outside much, but when it last ran, I have no idea.
Also how can I hook up an oil pressure guage to one of these engines.

Like Andy mentioned about maintenance related failures, there are reasons not to tear things apart for the hell of it. You can check the condition of a lot on the engine without taking it apart. If you have a dial indicator (cheap) you can check the shape your cam is in by measuring the lift at the valves. It's not uncommon for lobes to wear. You can do a leakdown test to see what's up with the valves and rings/bore. You can hook up the oiltank to the oil intake and see if the it's really doing some serious wetsumping, or if it took years to fill the crankcase as you found it. If the engine is completely intact you might want to consider leaving it alone but check what you can.
P.S I just remembered that leakdowns should be done on an warmed up engine. Is that a strict deal, anyone know? If so, how big is your oven?

If you plan on keeping the bike and making a good, reliable runner I would at least pull the head and examine the cylinder bores and check how well the valves are sealing by pouring kerosene into the ports and looking for leaks into the combustion chamber. This will only cost you the price of the head gasket.

Heck the engine is already out of the frame.

Actually, my rule of thumb is if it has been sitting for a number of years, I go the full Monty and split the cases, examine the cam for wear, new rod bearings (mike the journals and check for roughness), split the crank and clean the sludge. Then strip the head and replace intake seals and guides if necessary and clean up the valve seats. Also check the valves and springs. I have seen rust on valve springs in engines that have sat a number of years.

That way you can thoroughly clean and beadblast the cases polish the timing cover and primary and make the engine worthy of putting into that spiffy re-done frame!

It also gives you piece of mind that everything is happy in there!

OOPs, I mean peace of mind not piece.

If it was mine I would split the cases as there are a couple of known issues with the 72 motors. the oil pickup needs to be relocated from the front to rear of sump, the tang washer on the camshaft is known to break off. It would not hurt to do the CNW reed valve on the breather as it is basically a bolt on with the 72 cases. and as Ron said a good look at the head and cylinders also.



windy

I would pull the head, cylinders and timing cover off. Check valves like Ron said, examine the bores and pistons. With the cylinders off you can see the cam lobes. The timing chain tensioner on the 72 tends to shed metal particles into the oil, it should be replaced with the version with a rubber pad. I wouldn't crack the cases unless the cam looked nasty.

htown16 said:

I'm expecting my frame and assorted bits back from the powder coaters soon and I'm trying to figure out how to proceed with the build. I'm trying to figure out whether to install the engine as is and try to get it running to check it out or whether to gut up and tear it down and rebuild it before it goes in the frame. I'm doing a frame up build. Engine is a late 72. Norton owners club says it should have superblends based on seriel number. Clock shows 12,000 miles. Sump was full of oil and engine seems to turn smoothly with good compression. Bike wasn't super rusty, so I don't believe it sat outside much, but when it last ran, I have no idea.

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I'd tear it all down. Like Ron says you will then have peace of mind knowing that everything is perfect. Worth the extra effort and you already have the engine out of the frame. You don't want to have to take the engine out again.

Consensus seems to be tear it down and have a look. I've got all the parts together to build the frame up into a roller. Then do transmission. Then do engine. Expect some questions.

I'm in just about the same position. Ready for p/c and everything apart. Thinking about sending the motor or head and bottom end to Memphis Motor for a rebuild. Know it will need the superblends, and will be a good time to bead blast everything before I put it all back since I have gotten most of the hardware and cases looking good.

Dave
69S project

Hi Mitch,

Once again, I'm with RonL on this one. You've got a 35-year-old Norton from an unknown string of owners, in unknown condition, with the potential of being a really special ride. I've lived in Houston several times in the past (I bought my first Norton there in 1973), and know that there are many competent machine shops looking for work. Remove the head assembly and send it out for valve work; at least replace the seats and springs and regrind the valves. The shop can check the cylinders as well. New rings are 100 bucks a set. Your bike will be starting its new life with full compression.

While the head is out, you can follow Ron's suggestion and open the crankcase. My recent experience rebuilding my Mk3 featured a lot of dead time waiting on parts and vendors; rebuilding the engine fits into these dead times.

Concerning the transmission, it is painfull to remove the mainshaft with the gearbox in the cradle, so now is the time to open the gearbox up on the bench and take a look. Replacing the layshaft bearing is straightforward on the bench; the original part is failure-prone and should be replaced by the newer superblend part. All of the seals should be replaced; they are too old and brittle.

It's a fun project. You'll be ready by spring.

Thanks for all of the replies. I believe I have found a machine shop I trust, Rae Machine in Pasadena. Anyone in this area use them before? He skimmed my brake disc and did a good job. Seems to be in tune with older bikes. If anyone wants to track the progress of the build, I have another thread going titled "Mitch's Basket Case". I haven't posted anything in a while but I should have some new pictures next time I go out to the shop. Next on the agenda while I'm waiting on the powdercoating is to do the transmission. I have a gasket set and new superblend layshaft bearing in hand. Need to get a dial guage so I can check the play on the layshaft per Old Britt article.

I suspect there are many excellent machine shops out there. The trick is to find them. Reputations can be misleading. I had a head butchered by a local machine shop that was recommended. In fact, they even managed to lose some of the valve keepers. Said they were never there. I've even had one of our more popular parts supplier, who does machine work too, do a less than satisfactory head for me. The thing about CNW and Memphis Motorwerks is you know what you are going to get. If for some reason something is not right they'll make good on it. The old live and learn adage doesn't apply with them.

This is going to look like hedging my bet on this, but I'm just making my position clear. Ok, I am hedging.

I would take a motor like this apart if it looked like anyone had been in it. There are always signs. The oil line to the head in the photo from September isn't promising, both the method of repair and what might have happened to make it necessary. Just looking at a bike you can tell the difference between misuse and disuse. The fact that this entire bike is being completely restored makes me wonder why the the question of whether or not to rebuild the engine even came up.

Unless there are compelling reasons to go through an engine though, I just wouldn't do it out of hand. Derek's bike up in Whitehorse is an example of a bike that's original, unmolested, been vetted, and runs fine. It is an exception, I know. All I'm saying is that I've heard of people dropping thousands in a motor that went south and others that keep their hands off'em and do fine. You have to at least entertain the possibilites. My general advice would be to take the money from the engine overhaul budget and get a TriSpark, RMA camchain adjuster, oilfilter, and a pair of FCR's and wear that motor out. Then rebuild it.

There are a lot of things you "can" do but there are only a few things you "have" to do.

1. Cam wear, pretty sure that was an 850 problem. Seems like the hardening was suspect on a lot of the 850 parts.
2. Oil pickup, yeah, if you race the snot out of it. I mean on a track-race-the-snot-out-of-it. Otherwise forget it.
3. Superblends. Only if you are really confident they are in there.

Just saying.

I've used Rae for cylinder boring and had good success although you'd never know it by looking at his shop. Personally, I'd send the head to Memphis Motorwerks if it needs guides. No doubt Rae could do a valve job.

htown16 said:

Thanks for all of the replies. I believe I have found a machine shop I trust, Rae Machine in Pasadena. Anyone in this area use them before?

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I take ALL of my old-bike machine work to Kerry and Pete and I have for years, they are "real" Machinists (not "just" button-pushers) if you give Pete 2 parts that don't fit together he can and will make you a nice, clean adaptor (Pete's slow but he is GOOD and he cares, that's rare anymore).

Unclviny

Just stripped the transmission down this weekend. Considering its general condition, no doubt the engine will be stripped also.