Anyone as experience with 920 engine?

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lcrken said:
yves norton seeley said:
Hi there,
I just receive a antsword from Maney, and he says that you can not bore a 820 Maney cylinder to 920
His proposal is to buy a Maney 920 cylinder
I am surprised that nobody give me some background about 920??
Thanks
yves
Click to expand...

Hi Yves,

I have a lot of personal experience with 920s, but it's almost all on race bikes, and all with sleeved iron cylinders. Since you are looking at an alloy cylinder for street use, I didn't think my experience would be of much use to you. I have put together one 920 engine using a Maney cylinder, but it hasn't been run yet by the friend I built it for, so I don't have any feedback yet.

I've posted quite a bit here on the forum about the sleeved iron cylinder 920s I've run. If that sort of data is of interest to you, let me know, and I'll dig up the links.

Ken
Click to expand...

Thanks Ken,
Of course I am intrested
Yves
 
How do you stop the combustion chambers from leaking into each other with that size bore - do you bore off-centre - then what do you do with the squish-band ?
 
acotrel said:
How do you stop the combustion chambers from leaking into each other with that size bore - do you bore off-centre - then what do you do with the squish-band ?
Click to expand...

I will use the Jim Schmidt system for the head gasket and will adapt the pistons to the squish, I did it already with the 820 pistons, not a big deal
and if combustion chambers leaking into each other, I will find the solution, believe me!
 
I've looked a doing the 920, but it seems there would be only about 1mm between the bores.
 
acotrel said:
I've looked a doing the 920, but it seems there would be only about 1mm between the bores.
Click to expand...
If you go to the website from Maney you will see on the copper gasket more as 1mm between the bores
yves
 
I have a set of iron 920 cylinders in the workshop. I will take a look at them and check sleeve to sleeve clearance. From memory the sleeve lip is cut in the centre section, so of course it is tight.

This is not such new ground though, it has been done a fair bit over the years. The 81mm cylinders I have were made for Grasstrack/motocross sidecar use and have every other fin ground off for mud clearance reasons! It was popular once, but not easy to find anyone that wants them these days.

But, new Steve Maney barrels would be the way to go Yves.

Assuming they are still good and on standard bore I might be interested in the 77mm barrels for my race bike. I have some pistons already for 77mm.

But I hasten to add I am on a retirement income ;-) But I do live in France and could probably collect!
 
SteveA said:
I have a set of iron 920 cylinders in the workshop. I will take a look at them and check sleeve to sleeve clearance. From memory the sleeve lip is cut in the centre section, so of course it is tight.

This is not such new ground though, it has been done a fair bit over the years. The 81mm cylinders I have were made for Grasstrack/motocross sidecar use and have every other fin ground off for mud clearance reasons! It was popular once, but not easy to find anyone that wants them these days.

But, new Steve Maney barrels would be the way to go Yves.

Assuming they are still good and on standard bore I might be interested in the 77mm barrels for my race bike. I have some pistons already for 77mm.

But I hasten to add I am on a retirement income ;-) But I do live in France and could probably collect!
Click to expand...

Ok Steve
The day I will strip the engine (november) will send you a PM
The 820 barrels are on standard bore and in perfect condition
Keep you posted
Yves
 
I have a 920 kit in a road bike , parts were supplied by Norvil , machined & fitted by a local engineer .
He was not impressed by the quality of the pistons , but it has served me well for many years with no problems .
 
dero said:
I have a 920 kit in a road bike , parts were supplied by Norvil , machined & fitted by a local engineer .
He was not impressed by the quality of the pistons , but it has served me well for many years with no problems .
Click to expand...
Thanks Dero,
What about the power?
 
The theory in Australian historic racing is usually 'big is better'. However some people find that when they go there, the results are not as good as expected. We have Manxes and G50s as big as 650cc, however they often don't perform as well as the 500cc versions. My friend has just converted his 650cc Triton to 750cc and is encountering problems he never expected. When you go bigger bore, the piston weight usually increases. That affects the way the motor spins up and it is not just a matter of re-balancing to correct it. A much better way to go might be use Jim's light pistons and long rods and don't increase the bore size.
 
acotrel said:
A much better way to go might be use Jim's light pistons and long rods and don't increase the bore size.
Click to expand...

Please read again.

Yves has been using JS crank, rods, cams, lightweight pistons, distribution and carbs with Maney cases, cylinders and exhaust together with a Fullauto head and a TTI gearbox. His engine as well as the entire bike is up there with the very best exemples of road bike to be found anywhere.
Just sayin'...

Yves and I are very good friends, we ride our bikes together frequently.
 
lcrken said:
These are links to some of the threads I've posted to about 920 engines. I know there are some more, including some with dyno results, but I'll need to find some time to hunt them down.


920-t13102-30.html

rgm-920-kit-t22368.html

920-race-engine-teardown-t20480.html

norton-ready-for-bonneville-speed-trials-t20141.html

920cc-conversion-t17880.html

Ken
Click to expand...

Hi Ken,
This is really intresting, thanks a lot
I plan to buy a 920 Maney cylinder, pistons from Jim Schmidt and the JS 3 cam
Your opinion please?
Yves
 
The power on mine is a nice improvement , strong throughout the range , 4S cam .
I also fitted Keihin flatslides at the same time , so hard to tell how much improvement was due to the 920 .
 
Hi there,
I find two companies, on in France and one in the Netherlands that can do Nicasil treatment on the cast iron sleeves from the Maney cylinders;
I plan to do it on the 920 cylinders, Jim Schmidt can provide piston rings that match Nicasil.
Anyone have experience with the JS 3 cam?
Thanks
Yves
 
yves norton seeley said:
Hi Ken,
This is really intresting, thanks a lot
I plan to buy a 920 Maney cylinder, pistons from Jim Schmidt and the JS 3 cam
Your opinion please?
Yves
Click to expand...

Sounds like a good plan to me. You might also think about using "waisted" fasteners on the cylinders and head. They allow a bit more spring effect from the fasteners to cope with the thermal expansion of the alloy cylinder and head. We had a couple of threads on the subject not too long ago. I'll see if I can find the links.

Ken
 
lcrken said:
yves norton seeley said:
Hi Ken,
This is really intresting, thanks a lot
I plan to buy a 920 Maney cylinder, pistons from Jim Schmidt and the JS 3 cam
Your opinion please?
Yves
Click to expand...

Sounds like a good plan to me. You might also think about using "waisted" fasteners on the cylinders and head. They allow a bit more spring effect from the fasteners to cope with the thermal expansion of the alloy cylinder and head. We had a couple of threads on the subject not too long ago. I'll see if I can find the links.

Ken
Click to expand...

Maney barrels come with fasteners to suit. Do you know which ones are different from original Norton/CNW ARP?
 
SteveA said:
lcrken said:
yves norton seeley said:
Hi Ken,
This is really intresting, thanks a lot
I plan to buy a 920 Maney cylinder, pistons from Jim Schmidt and the JS 3 cam
Your opinion please?
Yves
Click to expand...

Sounds like a good plan to me. You might also think about using "waisted" fasteners on the cylinders and head. They allow a bit more spring effect from the fasteners to cope with the thermal expansion of the alloy cylinder and head. We had a couple of threads on the subject not too long ago. I'll see if I can find the links.

Ken
Click to expand...


Maney barrels come with fasteners to suit. Do you know which ones are different from original Norton/CNW ARP?
Click to expand...

OK, one last edit to get the info correct.

Steve's cylinders use different thread (3/8-16) head bolts and longer studs. The cylinder through bolts are the same as stock Norton, unless you are getting shorter cylinders or one without two of the counterbores for the bolt heads).

Ken
 
lcrken said:
Unless he's changed them since I bought mine, Steve's cylinders use different head bolts (3/8-16) and studs (longer). The cylinder through bolts are the same as stock Norton, unless you are getting shorter cylinders or one without two of the counterbores for the bolt heads).

Ken
Click to expand...

Right Ken, so basically the CNW ARP kit with waisted bolts cannot be used with Maney cylinders.
 
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