Project update: very good, then a very bad day

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Coolhands said:
Just stuck my finger in the hole. This ones not gonna polish out. :)
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That's a shame
I remember rebuilding a Yamaha fz 750 for someone that had overtightened the drive chain and wrecked the sprocket drive bearing
When I was stripping the engine I was shocked to find one of the piston circlips completely missing!
The gudgeon pin had moved to one side and scored the barrel perfectly
There was no burr on the gudeon pin at all but the score was deep and the length of the engines stroke
I phoned the owner to see what he wanted to do
He wanted me to carry on and change the bearing, rebuild the motor and fit the piston with a circlip
I assumed it would smoke now the gudeon pin was back in the correct position and not filling the score in the cylinder wall but it didn't!
The bike ran perfect,no smoke nothing! I couldn't believe it
If that had been my bike it'd smoke like a pig
 
MichaelB said:
RGM lists sleeves for the 750.
Is it general knowledge the 750 doesn't sleeve well?
I'm not up to speed on that.
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Me neither, the only thread i saw on it was mostly all bad then Rohan was sayin they were all out to lunch.
 
worntorn said:
RGM sells new strengthened 750 barrels with the 850 type through bolt arrangement.
Unfortunately , they are a bit pricey at 595gbp.
On the other hand, even if it was possible, liners and machine shop costs would add up.
G81 is planning to offer
alloy 750 and 850 barrels sometime soon.
Motoparts in Edmonton show a used 750 barrel for $700 cdn, which is about 400 GBP.
Judging by the pricing, they are aware of the shortage of good used 750 barrels.
The strange thing is, the used 750 heads can be had for cheap whereas the 850 heads, especially RH 10, go for big prices on eBay.


Glen
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What you figure the 750 jug shortage is about? Seem to come up regular on ebay
 
I'm sorry you're in difficulty. Have you contacted AN about whether they have plans to produce new stock, or have any suggestions on potential sources?
 

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

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...
www.accessnorton.com www.accessnorton.com

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

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...
www.accessnorton.com www.accessnorton.com
Dave m

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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My understanding is that the issue with 750 barrels is that there is too little material above the flange area and that is where they can break.

Clearly, boring out to insert a liner makes this area even weaker as the hole required is large, and the liner itself adds no strength to the casting.
 
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Rohan added & wasn't challenged

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

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...
www.accessnorton.com www.accessnorton.com

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

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...
www.accessnorton.com www.accessnorton.com
Rohan said:
Thin walled sleeves are very common in the automotive world - well proven technology.
Yes, even in 16H Nortons and myriads of dommies !!

So why then are Anthony Curzon and Peter White of the NOC mentioning they have had more than a few engines (750 Norton engines) done with this ? And even recommending folks to do it.

Just because you have doubts doesn't mean it can't be done, successfully, by skilled operators.
LA Sleeve have sold gazillions of sleeves for all types of engines.
Search here and see how many folks mention them...
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The prob with past stuff tho is 1/2 the pix are gone, broken links abound & on this one, Rohan is gone.
 
74ok said:
Rohan added & wasn't challenged

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

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...
www.accessnorton.com www.accessnorton.com

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

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...
www.accessnorton.com www.accessnorton.com

The prob with past stuff tho is 1/2 the pix are gone, broken links abound & on this one, Rohan is gone.
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My recollection of that thread is that yes it’s possible to line 750 barrels. And many have done so. But nevertheless it is accentuating a known weakness.

So it might be fine… it might not.

Personally, if I was undertaking an expensive post blow up rebuild, I’d be feeling a tad on the risk averse side !
 
Coolhands, you know you are lucky to be on one piece. Leaned over at 65-70mph and having that thing lock up would have been painful. High side get offs suck.

On the other hand... What we have here is a great opportunity to build a good reliable Norton engine. Choose wisely.
 
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another scary thing to consider...once the wrist pin has drifted all the way to one side and begins to chew into the cylinder there is very little engagement of the pin in the piston on the other side
 
Fast Eddie said:
My recollection of that thread is that yes it’s possible to line 750 barrels. And many have done so. But nevertheless it is accentuating a known weakness.

So it might be fine… it might not.

Personally, if I was undertaking an expensive post blow up rebuild, I’d be feeling a tad on the risk averse side !
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This is the part that jumped out at me but the referenced NOC link is broken

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

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...
www.accessnorton.com www.accessnorton.com

Rohan said:
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 (?)
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Could be these 2

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

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...
www.accessnorton.com www.accessnorton.com
Rohan said:
So why then are Anthony Curzon and Peter White of the NOC mentioning they have had more than a few engines (750 Norton engines) done with this ? And even recommending folks to do it.
Click to expand...
 
According to LA Sleeve and Melling typical sleeve was thickness is about .094 which means the cylinder needs to be opened up something less than .0180 to achieve a proper fit. I would think that a 750 undergoing such a procedure would need spacers between the fins...

I have read in this forum that 750 sleeving has been done, but when I was faced with the same choices I phoned the services I trust and was told by all that a 750 at .060 over was too much for reliability.

I purchased a new 850 style cylinder from A/N giving me plenty of new bandwidth to worry about something else.

Coolhands you will burn a lot of time rebuilding the bottom end during that time keep a lookout for a new or serviceable cylinder; you'll find one.

Best.
 
When I put the sleeves in the 920 engine one skirt broke as I was handling the cylinder. It lightly touched on the edge of the mill table, but that was enough to do it. Those sleeves finished up at 70 thou after boring.
That is 70 thou of extremely long wearing but fragile spun cast material. It is quite different from 70 thou of steel, stainless steel or even aluminium.
So I had to order a new sleeve and start over on that cylinder.
It was a relief to finish the sleeves in the barrel and slide it into the crankcase, where I hope it remains for a very long time!
I can't imagine liner skirts at .030" in that material. You could break those out with fingers!

Glen
 
Fast Eddie said:
My recollection of that thread is that yes it’s possible to line 750 barrels. And many have done so. But nevertheless it is accentuating a known weakness.

So it might be fine… it might not.

Personally, if I was undertaking an expensive post blow up rebuild, I’d be feeling a tad on the risk averse side !
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Especially not being able to find or look at something solid indicating otherwise.
 
Thanks for everyone for the input! I was able to source another engine here on the forum to put in for now. Then I’ll take my time to see what’s salvageable from the current engine and start a rebuild as time, parts and funds allow.
 
Outa curiosity, asked a local shop for the cost of a sleeve job, 750 commando jugs.

500 bux labour + sleeves + tax, didn't get into if a good idea or not.
 
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