travel trials

acadian · Jul 24, 2018

Fast Eddie said:
Hope you know what you’re doing... I had my combustion chamber ceramic coated and chunks came off and took the bore with it !

Well, I hope the coater knows what he's doing! I enquired about this problem and he's assured me that proper prep is the key.. fingers crossed!

Fast Eddie · Jul 24, 2018

Yes and no...

Yes prep is super important.

But mine flaked off in areas where, in my opinion, it had been applied too thick. The coating had ‘puddled’ around the valve seat area. So in other words, application is just as important.

It needs to be very thin and very even, if it’s not, send it back.

FWIW, Jim removed all trace of the coating when he did my head work, and, I can’t tell ANY difference. No down side at all. Even in recent track events during heat waves! Perhaps solving a problem that isn’t there ??

acadian · Jul 24, 2018

Fast Eddie said:
Yes and no...

Yes prep is super important.

But mine flaked off in areas where, in my opinion, it had been applied too thick. The coating had ‘puddled’ around the valve seat area. So in other words, application is just as important.

It needs to be very thin and very even, if it’s not, send it back.

FWIW, Jim removed all trace of the coating when he did my head work, and, I can’t tell ANY difference. No down side at all. Even in recent track events during heat waves! Perhaps solving a problem that isn’t there ??

That's sensible, I will enquire about this point as well. I had assumed that, because the coating is so thin and brittle, if any did flake off it would be unlikely to cause damage.

I'm also having the skirts coated with the slippery stuff

worntorn · Jul 24, 2018

Nigel, I would go further to say the coating can create a problem that isn't there...

Glen

mdt-son · Jul 24, 2018

comnoz said:
My first Norton failed in the 70's. It was an N15 and the nut came loose on a little ride out of town. I didn't have a real wrench with me so just tightened it with pliers as best I could. About the 3rd or 4th time I stopped to tighten it there was nothing left of the threads.

Hi Jim, which measures will you be taking to secure the nuts now that the Z-screws obviously don't hold up? Is safety wiring the only alternative?
How do bronze inserts hold up if the exh. nut come loose and need retightening?

-Knut

Fast Eddie · Jul 24, 2018

worntorn said:
Nigel, I would go further to say the coating can create a problem that isn't there...

Glen

Well yes, it did on mine !

comnoz · Jul 24, 2018

mdt-son said:
Hi Jim, which measures will you be taking to secure the nuts now that the Z-screws obviously don't hold up? Is safety wiring the only alternative?
How do bronze inserts hold up if the exh. nut come loose and need retightening?

-Knut

Looking at the impressions left by the setscrews it appears that they did prevent the nut from turning. The nut simply pounded it's way straight out and did not unscrew.

I had hard bronze inserts in the head that was on the bike before the Fullauto. I did not use anything to secure the nuts I was using then. They never gave any problem in well over 100,000 miles.
I will not use any locking method after I install inserts in the Fullauto -but some locking method might be advisable with the standard exhaust system.

I have yet to see the threads in a hard bronze insert fail from running loose.

I have seen the threads on an Andover bronze nut wiped out when they were run loose in one of my inserts.
I do not recommend bronze nuts when using my inserts. The bronze nuts are quite soft.

Son of Siredward · Jul 24, 2018

Great to see you and the family for the short time at the show. Glad you had a safe trip and that the blow to make you truck the bike didn't happen until you not too far out and on our way home.

Atlas Commando · Jul 25, 2018

I still carry tools when riding my HDs, conditioning from the past I guess. I got my first 'modern' bike in 1988. I think I tightened a battery connection once, and I changed plugs one time on the road.... I did some long trips with my buddies, constituting a mixed group of HD, Honda, Suzuki, modern Triumph, and BMW. The most common breakdowns were theft prevention electrics, and the most common brand issue was with the beemers. Not drawing any conclusions, it's a small sample size.
Trying to get somewhere close to the original thread, I look forward to someday putting some miles on my '72 Combat. I'll have to search the forum and see what people are carrying in their survival kits these days. I actually think a new wiring harness with better connectors will go a long way to keep the wheels turning. It seems most of my issues were electrical, not counting the broken rod, broken tappet, or parts that fell off my Atlas. (I was quite the "master" mechanic......)

mdt-son · Jul 25, 2018

comnoz said:
Looking at the impressions left by the setscrews it appears that they did prevent the nut from turning. The nut simply pounded it's way straight out and did not unscrew.
<...>

Thanks for your informative reply, Jim.

-Knut

comnoz · Jul 25, 2018

Since I was asked here is my opinion on combustion chamber coating on a Norton.

I think that if the coatings are applied correctly by a good experienced shop then
failure is unlikely -unless you have detonation which will cause immediate failure of the coating -no matter how good the job was.

My experience has been that head coatings will increase the likelihood of detonation
-combustion temperature will go up since not as much heat will be lost into the head.

So- you are probably safe if the engine compression and heat is low enough that poor
fuel will never cause detonation.

Since high heat and occasional detonation is fairly common on a STREET Norton, I would
probably pass on the coatings.

If you are building a RACE engine that will only see high octane race fuel then I would say
go for it.
It will help utilize the last bit of heat in the fuel. Jim

PS, I have had good results from the skirt and rod bearing coatings.

comnoz · Jul 25, 2018

I pulled my motor down last night.

The gasket-less head was as perfect as I could ask for. No signs of leakage.

But I was concerned about the fact that my oil consumption had increased and the cold engine noise had increased.
The cylinder walls looked great.

And so did the lightweight pistons

Until I got my mic out. The skirt on the left piston had collapsed by .010" so one piston was at .005 clearance and the other was at .015. Both were originally installed at .0045 clearance.

I guess it's back to the drawing board.

And by the way, after reading conflicting specs regarding the material used for the Vertex pistons and thinking they were 4032 -the response I got from Vertex was that they were actually 2618 alloy.

cliffa · Jul 25, 2018

comnoz said:
I pulled my motor down last night.

The gasket-less head was as perfect as I could ask for. No signs of leakage.

View attachment 5910

But I was concerned about the fact that my oil consumption had increased and the cold engine noise had increased.
The cylinder walls looked great.

View attachment 5911

And so did the lightweight pistons

View attachment 5912

Until I got my mic out. The skirt on the left piston had collapsed by .010" so one piston was at .005 clearance and the other was at .015. Both were originally installed at .0045 clearance.

I guess it's back to the drawing board.

And by the way, after reading conflicting specs regarding the material used for the Vertex pistons and thinking they were 4032 -the response I got from Vertex was that they were actually 2618 alloy.

View attachment 5913

Hi Jim, thanks for posting the video, loved your guide puller. You make everything look so easy.

I had to do a double take when I saw your second picture from today looking down the bore. I thought I was looking at the piston crown not a table top and that you'd added a piston port !

What would have caused the piston to collapse? it looks as though the skirts have hardly touched the bores.

Cheers,

cliffa.

comnoz · Jul 25, 2018

cliffa said:
Hi Jim, thanks for posting the video, loved your guide puller. You make everything look so easy.

I had to do a double take when I saw your second picture from today looking down the bore. I thought I was looking at the piston crown not a table top and that you'd added a piston port !

What would have caused the piston to collapse? it looks as though the skirts have hardly touched the bores.

Cheers,

cliffa.

I would suspect it was too much heat for the mass and heat dissipating ability of the piston.

I am working on the design of a new pair of custom pistons. I will be adding thickness to the skirt and the top and making the skirt longer for more wall contact to help keep it cool.

The downside is I will likely be adding 100 grams to the weight but if that's what it takes then that is ok.

madass140 · Jul 25, 2018

.010"!!! yikes thats a hell of a lot

Onder · Jul 25, 2018

Looking at the pix of the head, appears that the plugs are almost white in colour. Mine are the same which gives me some worry
about too lean. I lifted the needles all the way up bottom notch. Some small change but not much. Engine has about 2500 miles
runs well. I cannot remember ever getting plugs so white and clean. Is this normal?

comnoz · Jul 25, 2018

Onder said:
Looking at the pix of the head, appears that the plugs are almost white in colour. Mine are the same which gives me some worry
about too lean. I lifted the needles all the way up bottom notch. Some small change but not much. Engine has about 2500 miles
runs well. I cannot remember ever getting plugs so white and clean. Is this normal?

It is normal with unleaded fuel. The gray/brown color you used to get when the mixture was right with leaded fuel is no longer possible with no lead. The lead coating created the color.

Now with no-lead your choices are WHITE when you have complete combustion -but not necessarily the correct mixture-
or
DARK, which is cause by the soot from incomplete combustion. That could mean the mixture is way off [rich or lean] or ignition problems or low compression or anything else that would cause incomplete combustion.

The only way to tell for sure is a gas analyzer or a wideband O2 sensor.

My fuel mixture is feedback controlled at ~13.5-1 at no load to ~12-1 at full load.

comnoz · Jul 25, 2018

madass140 said:
.010"!!! yikes thats a hell of a lot

Yep, right next door to boom....probably lucky the exhaust threads gave out first.

lcrken · Jul 25, 2018

comnoz said:
Yep, right next door to boom....probably lucky the exhaust threads gave out first.

See, every lining has a silver cloud, or something like that.

Ken

Robert_Norton · Jul 25, 2018

Onder said:
Looking at the pix of the head, appears that the plugs are almost white in colour. Mine are the same which gives me some worry
about too lean. I lifted the needles all the way up bottom notch. Some small change but not much. Engine has about 2500 miles
runs well. I cannot remember ever getting plugs so white and clean. Is this normal?

Grabbed a little color from Jim's picture to blow it up and see what it looked like from a larger perspective. From one representative point only, of each plug:

.

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