A Good Ride Spoiled

After 45 years on my Norton only 2 times it didn't make it home running back in the early 80s 100 miles from home the Boyar black box failed and couldn't fire up, that was a week after the major fire, the fire damaged the black box and it was the first run after rewiring all the melted wiring, it came home in the back of a Ford station wagon, second time was a few years ago when the chain threw a retaining clip and wrapped around the inner primary case, it was jammed solid 4 miles from home after giving it a big hand full from the lights, came home in my trailer, 2 other times in its life its came home running on one cylinder once with a broken coil (it had lost the bottom half of the coil body) and the other a loose carb manifold, it was dark at the time and about 50 miles from home, both were easy fix, lucky had a spare coil laying around and the manifold retighten.
So not bad for 45 years of nearly trouble free, since 1980 my Norton has had a lot of good upgrades and its been very reliable.

Ashley

“ a broken coil (it had lost the bottom half of the coil body)”

Lucas coil?

Hey Mike hows it going on the teardown?

850commando said:

Hey Mike hows it going on the teardown?

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Not much time to work on it yet. Just drained the nearly full tank today. Will see how far I can get next few days.

I feel your pain

concours said:

I feel your pain

View attachment 19087View attachment 19088

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Just another troublesome part on a power valve.... ouch!

Schwany said.
Sadly, I spend at least 80% of every ride I take on my Norton wondering when it's going to break, and if it locks up whether I'll make to the side of the road before I get hit from behind. I miss being young when I was invincible, and thought the Norton was bullet proof.

When we Had our Rally in Dunedin a few years ago, I had no hesitation about going up to Cape Reinga first, then after the rally, I went to see a mate in Bluff. Complete round trip including extra rides was 3150 miles. My 46 year old ignition switch gave trouble. I fitted a cheap car ign switch to keep me going. I did hear a rattle up[ Saint Arnaud way but didn't cause a problem. I just about shit myself though when I had the tank off looking for the wiring problem, 'zI found that I had lost my head steady bolts. My tight main Isolastics worked a treat.

In a nut shell. If your bike has been put together properly, and you don't do anything stupid, just get on it and ride it.

And carry an exhaust ring spanner with you.

Head is off.





Underside of gasket:

Possible blow though point? Narrowing and thinning evident:

Cant see any obvious valve damage on lower side faces. Hard carbon build up on number one side mostly.
Cylinder walls looked ok to my untrained eye.
Piston tops have no valve notches, no obvious size markings. Number one side does have some kind of ding about in middle, looks like a center punch mark? Edges raised.

kinda looks like something was moving across between the pushrod tunnels and the cyl's. is that a copper gasket? have rotated the crank to move the pistons down in the bore, just as check for any unhappy scratching?

850commando said:

kinda looks like something was moving across between the pushrod tunnels and the cyl's. is that a copper gasket? have rotated the crank to move the pistons down in the bore, just as check for any unhappy scratching?

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Yes copper.

I know some people love copper gaskets but I've had good luck with flame ring composite type which come in the Andover kit. Looks like you might need to have both the head and barrels lightly skimmed.

htown16 said:

I know some people love copper gaskets but I've had good luck with flame ring composite type which come in the Andover kit. Looks like you might need to have both the head and barrels lightly skimmed.

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I'd heard that copper is more difficult to get a good seal if the faces are not dead flat/smooth, but that they should get you home if they blow....while fiber are more forgiving to seal, but when blown you are stuck. Not sure I believe that now.

From reading other threads, seems like taking barrels off at this stage is best practise to inspect pistons, cam, followers.

What is a good way to remove the carbon crud? Tried a brass wire hand brush and only a bit has come off.

I use a short piece of aluminum flat stock sharpened on one end to scrape the big stuff off followed by a brass brush in Dremel tool. Soak with carb cleaner.
The composite gasket has a soft metal ring around the cylinder bore.

htown16 said:

I use a short piece of aluminum flat stock sharpened on one end to scrape the big stuff off followed by a brass brush in Dremel tool. Soak with carb cleaner.
The composite gasket has a soft metal ring around the cylinder bore.

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Ha! Thats what I just did the decarbon scraping with. Had a bit of soft alu scrape stock, already with a 90 deg bent at end. Worked fairly well.
I can now read "STD" on rhs can, as well as "A" , "RF" and "ID 66" on that can.
Other side has "LF" , "B" , "ID 13" , and barely visible "S". Cannot make out a full STD that side.
Do these markings mean standard size, not oversized? Do the ID's inform anything useful?

Yes, definitely blowing between cylinder and pushrod tunnels, and it’s been doing it for a long time, so that’s most likely where your smoking is coming from (pistons sucking oily mist in).

I would certainly remove the barrels for a look at the pistons and rings, and follower faces, if I were you. Also a good opportunity to peer into the cases for a look at the cam. If the pistons are good I’d try and leave them on rather than have to get into the whole sourcing of correct circlips etc!

Ditto the valves, to check for worn or loose guides. And maybe treat them to a quick lapping in.

You’ve done the hardest job, getting the bloody head off, the other hobs are easy in comparison!

Yes, often harder to get copper to seal against minor weeps as good as a flame ring some say, but the advantage to copper is that it’s less likely to ‘blow out’ completely and leave you stranded. So both have their fans. However, the copper gasket should not have failed as it has IF both surfaces are flat and the clamping force (torque) was correct. So checking the surfaces is important. Maybe also check the studs are fully secure, the 3 studs in the head can pull the threads, losing torque.

Do be ULTRA careful scraping that carbon off, any crud that falls down your pushrod tunnels will turn into great grinding paste and chew up your cam followers and follower tunnels.

On the new gasket, I suggest you use a standard head gasket, not copper. As FastEd noted, copper certainly has some advantages but a standard gasket is much more forgiving of any head/block unevenness or tightening torque variation.

FWIW, when a copper head gasket is installed for high performance engines, it is usually in conjunction with a metal O-ring which requires a groove to be machined in the top of the block/barrels.

Barrels off, head and barrels skimmed. Flame ring gasket. New rings if pistonsand bores all good. New guide seals if guides good.

Check pistons for wear in the ring lands while in there. My bore and piston/cylinder clearance were fine but pistons were worn where the rings ride.