Fred Brown's Norton Combat wins OC Vintage bike show
- Thread starter jseng1
- Start date
jamesp
VIP MEMBER
- Joined
- Aug 17, 2011
- Messages
- 486
Looks like a great monthly get together. Wish it were closer!
- Joined
- Jun 30, 2012
- Messages
- 14,004
Is this a nice Commando ? Is there one dealer who sells all the bits to convert a normal Commando into a production racer. I think I might like one of those ?
Last edited:
nortonmargie
VIP MEMBER
- Joined
- Jan 16, 2022
- Messages
- 187
https://nycnorton.com/ This shop builds bespoke Seeley framed Norton racers. They do great work but are NOT cheap. Have several thousands laying around?Is this a nice Commando ? Is there one dealer who sells all the bits to convert a normal Commando into a production racer. I think I might like one of those ?
- Joined
- Nov 26, 2009
- Messages
- 3,216
Here's a better photo of Freds show winner. This bike not only looks good. Its also very fast and reliable. Its a Combat motor with all the upgrades including lightweight pistons and longer rods so it won't blow up when he's reving it over 7000RPM. It has the intake port sleeves to give it a wider power band and the hi flow Smoothbore carbs along with a performance radius cam and state of the art valve train. Its a hot street bike and he's not afraid to use it as such.
An expert build by Dean Collinson’s TT Cycle, Leona Valley, CA
Freds bike at rumpity hot cam idle.
An expert build by Dean Collinson’s TT Cycle, Leona Valley, CA
Freds bike at rumpity hot cam idle.
- Joined
- Jun 30, 2012
- Messages
- 14,004
I suggest there are three motorcycles which might be worth manufacturing - the Seeley 7R, the Seeley G50 and the Seeley Commando . In race form they are excellent, however the Seeley Condor street bike never went into production. The Mk3 Seeley frame might be the best - the centre of gravity affects the handling.
What I am suggesting could give rise to the opportunity of getting good rideable motorcycles which can actually be worked on by their owners.
We currently have the capability to remanufacture all of the components. And we can also buy bits from China.
What I am suggesting could give rise to the opportunity of getting good rideable motorcycles which can actually be worked on by their owners.
We currently have the capability to remanufacture all of the components. And we can also buy bits from China.
- Joined
- Jun 30, 2012
- Messages
- 14,004
One thing which I started to do was make a spine frame for the Chinese 125cc CT110 Honda copy motor. I was going to build a 125 cc version of the 250cc Aermacchi Ala D Oro racer. The motors are cheap and Ace Airstream 250 Tanks, seats and forks are available
- Joined
- Jun 30, 2012
- Messages
- 14,004
I suggest that what we have in Commandos is too valuable to lose, simply because of modernisation. Retros have potential.
There was a thing I did not realise, until a very wealthy guy told me - the 1959 7R AJS was the fastest - I think that is what Guy (Michelle) Duff rode on the IOM and beat the MV 350 s.
When we start fitting 4 valve heads etc. , we simply up the ante.
Racing two-strokes is really stupid. The 300cc MotoGP Spec. bike might do something at a cost. Could we build one in our backyard ?
It might be good if organisations were developed to specialise in certain genres. The Seeley 7R AJS was the best ever British single cylinder 350cc road race motorcycle. There is probably not even one race class to suit it these days, however a manufacturers award at race meetings might change that.Aah! Al Al Al
I've already told you the Mk4 Seeley frame is best.Do keep up.
And they are all currently being made.
There was a thing I did not realise, until a very wealthy guy told me - the 1959 7R AJS was the fastest - I think that is what Guy (Michelle) Duff rode on the IOM and beat the MV 350 s.
When we start fitting 4 valve heads etc. , we simply up the ante.
Racing two-strokes is really stupid. The 300cc MotoGP Spec. bike might do something at a cost. Could we build one in our backyard ?
- Joined
- Nov 26, 2009
- Messages
- 3,216
Yes the crank is stock but remember that the JS pistons are 1/3 lighter and the longer Carrillo rods reduce the intensity of the piston "snap" when it reverses direction. So the stress on the crank is reduced by at least 1/3 of what it was with the stock pistons and rods - and that's why it can rev beyond 7000RPM and still be reliable. And believe me Fred revvs it. He loves doing that.
Last edited:
- Joined
- Jun 30, 2012
- Messages
- 14,004
I have only ever once substituted lighter pistons into an engine without changing anything else. It made a significant difference to performance. With Triumph 650 motors, Thunderbird pistons were 7 to 1 comp. and Tiger 110 pistons were 8.5 to 1 comp. I don't think there was any difference in performance. the 8.5 to 1 pistons were heavier. And 12 to 1 comp. pistons were even worse. We used them with methanol. I used methanol in a 650 motor at 7 to 1 comp., and it was quicker than most. But I was young and believed bullshit, so I sold it. Jim's light 12 to 1 comp. light pistons and long rods look excellent. If I was going further with my bike, I would buy them.
I like the way he thinks.
- Joined
- Jun 30, 2012
- Messages
- 14,004
Getting the balance factor above 72% with a Commando crank, is difficult without drilling or reshaping the flywheel. The way the motor revs is also affected by the balance factor. With a low balance factor. the motor internals seem to be fighting themselves. The vibration energy has to go somewhere. With a high balance factor it goes through the rear wheel when the bike is speeding.
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
Agreed.
I recently fitted JS pistons and rods to a motor, I also fitted a correspondingly lighter flywheel and then had the lot dynamically balanced to 75%.
As you’d expect, the smoothness of the motor afterwards was night and day different.
But less obvious is this: with no other changes to engine, exhaust or carbs, it showed 7bhp more at the wheel on the dyno.
For those not familiar with playing around on dynos like this, 7bhp from one change is a freakin LOT !!
- Joined
- Jun 30, 2012
- Messages
- 14,004
Joe Craig claimed to have achieved 50 BHP with a 500cc Manx Norton. A very good Commando engine might achieve 70 BHP. If Nigel was up around that figure and gained 7 BHP, that is 'business excellence'.
- Joined
- Jun 30, 2012
- Messages
- 14,004
I have my doubts about a lighter flywheel. A race change up with close ratio gears probably uses crank inertia to advantage, when the revs are high. I always thought the heavy crank was a pain in the bum, but now I do not. The shape of the needles in the carbs makes a difference. If the taper is too quick, the heavy crank makes the mixture to richen too fast to get best power. I feed the throttle on, as you would with a two-stroke.
I know this sounds trivial, but it seems to work. I was amazed at how much extra go I got.
A lot of things I have done with my 850, have been similar to what I did with my T250 Suzuki. A two stroke is usually twice as difficult to get going. But some of the similarities are quite striking.
When I did the porting on the T250, I did the reverse - I converted crankshaft degrees for a good race cam to distance from TDC in the two stroke, and used Yamaha TD3 chambers. By 2003, the T250 had won 28 races and 4 championships.
You must think I am really silly.
I know this sounds trivial, but it seems to work. I was amazed at how much extra go I got.
A lot of things I have done with my 850, have been similar to what I did with my T250 Suzuki. A two stroke is usually twice as difficult to get going. But some of the similarities are quite striking.
When I did the porting on the T250, I did the reverse - I converted crankshaft degrees for a good race cam to distance from TDC in the two stroke, and used Yamaha TD3 chambers. By 2003, the T250 had won 28 races and 4 championships.
You must think I am really silly.
Last edited:
- Joined
- Apr 28, 2015
- Messages
- 181
What does a stock Commando dyno at? 45? 7hp on a dyno is massive.
acadian
VIP MEMBER
- Joined
- Mar 5, 2010
- Messages
- 1,446
And this is why I'm asking, the short stroke Molnar crank is 1800 pounds, but the steel flywheel is 650 pounds, so I'm thinking of going that route with the longer JS rods
