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Atlas Barrel - rebore to +0.060, hone or ditch?

Norton Models (not Commando or P11)

Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Mike T » Thu Apr 06, 2017 6:05 pm

Hello guys
May I ask for your advice concerning the barrel for my Atlas project bike? The engine was seized when I got the bike and I managed to remove the piston that was stuck. The barrel is in good condition but one of the bores is pretty rusty and I was thinking of getting it bored to the next size. But when I checked the pistons, they are already +0.040 over standard.
My question is, should I even attempt to go for a re-bore of +0.060 over standard or after looking at the cylinders do you think that it might only need a hone?
Thanks for your help

Here are a few pics of the barrel and I have more if needed:
Image

Image

Image

Image

Image

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1974 Norton 850 Commando MK2A
1964 Norton Atlas 750 ("Shep" project bike)
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Thu Apr 06, 2017 6:19 pm

from the pictures i doubt it would clean up at 060 with it at 040 now. you have to remember you are only removing 010 of materiel from the cylinder wall and THAT one is RUSTY.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Fast Eddie » Thu Apr 06, 2017 6:24 pm

There's no way a hone will clean that up and still leave it in spec for +.040 Pistons IMHO.

Gotta be worth seeing if they clean up at +.060 I'd say. It seems Pistons are available in +.080 sizes even.

I imagine such sizes are going to weakness the barrels somewhat, but unless you're racing it I would have thought it would be fine?
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby texasSlick » Thu Apr 06, 2017 6:41 pm

+1 with above replies.

I would look into nickel plate metal build up and honing back to + 040.

Check out <http://mxratracing.com/cylinder.html>

An advantage of nickel is a long wearing cylinder, similar to Nicasil. Nicasil maybe a harder, longer wearing surface treatment than nickel, but it does not build up lost metal.

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The Second Law (of thermodynamics) rules.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Thu Apr 06, 2017 8:14 pm

Checking whether it can successfully be sleeved might be a better option.

Folks here seem negative about this, but quite a few sleeves get sold for this purpose.
See if any of the bikeshops in your region can recommend someone.
Or ask say Mick Hemmings etc.
If done BEFORE the cylinder walls get too thin, this is a common automotive practice.

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Fast Eddie » Fri Apr 07, 2017 2:07 am

Rohan wrote:Checking whether it can successfully be sleeved might be a better option.

If done BEFORE the cylinder walls get too thin, this is a common automotive practice.


Maybe I'm having a 'brain fog' day or something, but I don't follow your logic.

If you bore the barrels out big enough to take a liner, then the casting will be much weaker than even the biggest overbore...
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Fri Apr 07, 2017 4:21 am

I have this chat with rohan before but if you argue with a fool it becomes hard to tell who is the fool. his comparing it to the automotive side has NO relevance to a norton cylinder.

Fast Eddie wrote:
Rohan wrote:Checking whether it can successfully be sleeved might be a better option.

If done BEFORE the cylinder walls get too thin, this is a common automotive practice.


Maybe I'm having a 'brain fog' day or something, but I don't follow your logic.

If you bore the barrels out big enough to take a liner, then the casting will be much weaker than even the biggest overbore...
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Bernhard » Fri Apr 07, 2017 6:03 am

Bore looks too far gone with all that rust, the normal method would be to have the rusted sleeve pressed out and another pressed into the barrel –I have had this done in the past HTH

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Fri Apr 07, 2017 2:46 pm

[quote="bill"][/quote]

Sleeving Norton cylinders is somewhat common, so your ignorance seems to be showing here ?

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Fri Apr 07, 2017 2:56 pm

Fast Eddie wrote:Maybe I'm having a 'brain fog' day or something, but I don't follow your logic.

If you bore the barrels out big enough to take a liner, then the casting will be much weaker than even the biggest overbore...


The sleeves aren't very thick, so you'd only bore it out enough to clean up the bore, and then fit the sleeve.
And if done BEFORE the cylinder is way past having any strength, this is a common repair method.
ie don't get it out to 0.080" over, and then expect to sleeve it.

I've got a sleeve for a 16H Norton, WD WW2 issue, and its quite thin.
I believe the correct spec is 'spun cast' .
These were used by the thousands it seems, and sidevalve donks are pretty hard on their bores.
So it was certainly good for them.
And sleeves have been available for dommies since, well, since dommies were available...
Hepolite supplied them, amongst others ?

Search for previous threads here on folks using these.
Plenty of good reports around.
LA Sleeve in the US have also been doing these for yonks, they do nothing else.

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Fri Apr 07, 2017 6:41 pm

speaking of ignorance, you have just shown yours. a .0625 wall sleeve will need a .125 over bore and that is as thin as la sleeve list's. PS it is NOT for a norton. from what you posted it would be an .030 wall sleeve, good luck on that one.


Rohan wrote:
The sleeves aren't very thick, so you'd only bore it out enough to clean up the bore, and then fit the sleeve.
And if done BEFORE the cylinder is way past having any strength, this is a common repair method.
ie don't get it out to 0.080" over, and then expect to sleeve it.

I.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Fri Apr 07, 2017 7:22 pm

There is something you are missing though - although the sleeves are thick - although not usually that thick ? - they are fitted and then the INTERNAL size is bored/honed out to suit.
So the resultant sleeve is not all that thick ...

The one in my old M20 engine is quite thin in fact.
And would seem to have done plenty of miles....

So have you tried any sleeves in any of your engines ??
Actual experiences....

500cc dommie sleeve - with spigot.
Not much thickness to it.....
Image
http://images.classicbikepartscheshire. ... 095000.jpg

And this post on the NOC Forum.
Some familiar names there with good reports.
http://www.nortonownersclub.org/noc-cha ... /110372709

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Fri Apr 07, 2017 10:29 pm

And a couple of pics on this very forum, for an Atlas that has been sleeved back to std

Image

Image

Wonder how they are holding up ?

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby dave M » Sat Apr 08, 2017 12:50 am

I understand that boring out the existing barrels with something like +80 weakens the existing lower cylinder not the cylinder casting as such, this can lead to a higher risk of the bottom part of the cylinder that protrudes into the crank case cracking off. Some people seem to have had bad experiences with liners others swear by them, many Norton parts suppliers certainly seem to offer them for sale, so I imagine that some people must have had good results with them. I myself have never had to fit liners in a cylinder but I am interested in hearing from anyone who has done so with good or bad results.

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Sat Apr 08, 2017 4:37 pm

When this was discussed previously here Dave, a whole string of folks came out of the woodwork with stories of their Norton being sleeved - sometimes only in one cylinder - after some tale of mechanical mayhem.
And seemingly still on the road.

Those 2 gents above in the NOC link are both club stalwarts, so if its good enough for them to have engines sleeved. They even recommend who to use for a good one...

And, it is very likely that a number of Nortoneers here could have engines which have been sleeved, and the current owners are not even aware of it, it used to be very widely done.
For many years Nortons only offered up to +0.40 oversize pistons, so once you reached there it got expensive (new cylinders). So Hepolite et all supplied sleeves to cover this. The sleeves I've seen have been less than 1 mm thick, so needing 80 thou is being generous ? That said, I've seen pics of cylinders with sleeves visible through the fins !!!, so not all sleeves may be the same initial diam... Its only relatively recently that +0.060 and even +0.080 pistons have become available - which is where flanges parting company woes really begin (?)

On that theme of not knowing that cylinders have been sleeved, this is a pic of a spare Enfield cylinder.
If you look closely, that fine line around the lip of the flange is yep - a sleeve.
Less than a mm thick, once installed - about 60 thou total.
Ignore the coat of anti-rust ( stops spares rusting away ).
I don't know the history of this - came with some junk - but the somewhat rusty bore says this was on an assembled engine - that later got water in it ..

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