Engine Modernization

chipdossjr · May 11, 2015

I love Nortons. I love everything about them. It has always been my dream, though to take the classic British design and breathe new life into it through use of modern technology in one of these old engines.

What I want to do is rebuild an 850 Commando with modern bearings, valvetrain, crank, rod, and piston.

The important thing in this build for me is the pistons. I come from the Motogp/ WSB side of cycling, so I cant help but see how big and inefficient these pistons are. I've learned that a lighter piston translates directly to more power and a more dynamic engine. I feel that this would be one of the best ways to advance one of these engines. Not only will the new piston be much lighter, but has much shorter skirts and smaller rings, so even less friction is present.

What I would like to do is find a way to make a modern superbike piston fit. The CBR 1000rr pistons happen to have the same bore as the 850. Perhaps some work could be done to make this happen? I should already be tearing so deep into the motor anything extra doesn't really matter. What will I have to do?

74ok · May 11, 2015

lotsa newer piston tech (+tons more) already out there & well tested, bigger prob is wallet size as far as available goodies goes

Nater_Potater · May 11, 2015

chipdossjr said:
What I would like to do is find a way to make a modern superbike piston fit.

I'm from the same mode of thinking as you, in that a longer rod with a higher wrist pin location would be the way to go, but Jim/Comnoz has had some dissapointing results with these in iron jugs. You can see the results at new-leakdown-results-t21149-30.html Run about two-thirds of the way down on page 3, but the whole thread is a good read. As always, Jim brings a lot of great data to the forum, with much heated debate in the mix.

Nathan

comnoz · May 11, 2015

chipdossjr said:
I love Nortons. I love everything about them. It has always been my dream, though to take the classic British design and breathe new life into it through use of modern technology in one of these old engines.

What I want to do is rebuild an 850 Commando with modern bearings, valvetrain, crank, rod, and piston.

The important thing in this build for me is the pistons. I come from the Motogp/ WSB side of cycling, so I cant help but see how big and inefficient these pistons are. I've learned that a lighter piston translates directly to more power and a more dynamic engine. I feel that this would be one of the best ways to advance one of these engines. Not only will the new piston be much lighter, but has much shorter skirts and smaller rings, so even less friction is present.

What I would like to do is find a way to make a modern superbike piston fit. The CBR 1000rr pistons happen to have the same bore as the 850. Perhaps some work could be done to make this happen? I should already be tearing so deep into the motor anything extra doesn't really matter. What will I have to do?

Well you better get some nikasil lined water cooled barrels first so you can get the piston to bore clearance down to the CBR's figure. While your at it you might as well cut the stroke in half too. Jim

L.A.B. · May 11, 2015

chipdossjr said:
What I want to do is rebuild an 850 Commando with modern bearings, valvetrain, crank, rod, and piston.

http://www.jsmotorsport.com/

http://www.stevemaney.com/

Diver3284 · May 11, 2015

I have this real passion to re-invent the wheel, but make it really, really round using the new technology available to us, so that the wooden carts we use will be more efficient..... I think...

Mark · May 11, 2015

^ Now.... was that really necessary?

as for Jim's comment -
Water cooling would be an improvement, or at least a step towards modernization.
Triumph is playing with the idea now.

grandpaul · May 11, 2015

Discussion of water cooling classic Commandos is rather conspicuous by it's absence on this forum, for good reasons.

Weight, parasitic loss of HP to drive a water pump, added complexity, and cost, would all net you quite near zero improvement (if any) on a classic Commando.

grandpaul · May 11, 2015

Just for grins...

Art's water-cooled Triumph

dennisgb · May 11, 2015

comnoz said:
Well you better get some nikasil lined water cooled barrels first so you can get the piston to bore clearance down to the CBR's figure. While your at it you might as well cut the stroke in half too. Jim

A man of few words...covered all of the bases in one sentence. I need to learn how to do that

Mark · May 11, 2015

"modernizing" a commando would mean evolution.
Air cooled, push rod, carburated engines are a thing of the past, relics of a previous era.

water cooling, OHC, fuel injection, etc. are what we have available if we wanted to try to bring
a commando up to todays specs.

OR.........

Appreciate the commando for what it is - an old bike.

dennisgb · May 11, 2015

Mark said:
Appreciate the commando for what it is - an old bike.

I would add "classic" old bike...with a little attitude and beautiful lines.

comnoz · May 11, 2015

Mark said:
"modernizing" a commando would mean evolution.
Air cooled, push rod, carburated engines are a thing of the past, relics of a previous era.

water cooling, OHC, fuel injection, etc. are what we have available if we wanted to try to bring
a commando up to todays specs.

OR.........

Appreciate the commando for what it is - an old bike.

Agreed, well maybe except the fuel injection part.....and the belt drive, and the forks and the shocks and maybe a couple other things.

Hobot · May 11, 2015

Peel will be water cooled inside and out and bores tapered so straighter rounder at temp so catch up when ya can. It was my poor ole mowers bore woes failure that brought Bore Tech to forum awareness and my pointing out short piston tipping troubles after powwow w local 2 tokes mechanic, then shorty after NYC Cummings came clean missing full race year with comnoz showing us the parts w crowns of tippy pistons beaten down eating oval bores which led to JMS periodic public showing of his testing his astray JE pistons to make sure its only excessively raced pistons that may need replacing like race tires. Tippy pistons get beat up but too warm tight fit piston is cool lower bore tends to stay there. With light pistons and JMS BSA or comnoz valve train and expensive crank and cases maybe 9000 rpm Commandos can live and tell.

Danno · May 11, 2015

The Commando has already been modernized-the 961.

cyclepsycho · May 11, 2015

Go to JSMotorsport.com
He has the lighter pistons and longer rods. They work great and that's a fact I can tell you from personal experience. More reliable, more power and efficiency. Its a no brainer. Your can improve or stay the same.

trident sam · May 12, 2015

Mark said:
^ Now.... was that really necessary?

as for Jim's comment -
Water cooling would be an improvement, or at least a step towards modernization.
Triumph is playing with the idea now.

I run a watercooled Commando, living in England there's not much choice :roll:
sam

72Combat · May 12, 2015

I'd like to see Marquez and Lorenzo up against Bruce Anstey on Replica Manx Nortons round the IOM. That would be worth watching :lol:

Rohan · May 12, 2015

72Combat said:
I'd like to see Marquez and Lorenzo ..... round the IOM

Marquez, Rossi and maybe it was Lorenzo and others were guests there, was it last year.
They took a tour around (in a car) and when asked it they wanted to race there, in chorus all said NO !!!!

Apparently it is said it takes 5 years to learn the track well enough to go fast.
Its peeling off BEFORE you can even see the corners that needs serious track knowledge.

But we diverge.
Triumph Thunderbirds, BM ST800, Yamaha TRX850 and Tenere 1200 are all updated Commandos ??

72Combat · May 12, 2015

But pistons aren't modern, they have been around for over 100 years.
Norton did modern some time back

Engine Modernization

chipdossjr

74ok

Nater_Potater

comnoz

L.A.B.

Moderator

Diver3284

Mark

grandpaul

grandpaul

dennisgb

Mark

dennisgb

comnoz

Hobot

Danno

cyclepsycho

trident sam

72Combat

Rohan

72Combat

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