Commando horsepower

First post here --

We are looking into building a 750 Commando engine for a Bonneville rig. If we do go ahead with this project, I would like any and all advice on how to get the most sustainable power.

We are restricted to 750cc.

Has anyone on here done dynamometer work with a Commando - ??

Thanks, Joe

JODAR said:

First post here --

We are looking into building a 750 Commando engine for a Bonneville rig. If we do go ahead with this project, I would like any and all advice on how to get the most sustainable power.

We are restricted to 750cc.

Has anyone on here done dynamometer work with a Commando - ??

Thanks, Joe

Click to expand...

Which class?

A destroked one Mk III 850 if youre ' stock ' might be toughest .





pnenultimate ' works ' 750 . 1975 . ( excuse the tripe , maybe someonell edit the picture off ) .



might save youre bacon





bob-920-special-666-t3279-15.html

If NORTON ' design ' is all thats required ,http://www.stevemaney.com/products.html if you have a rich aunty .

76 at the crank , for a 750 , seems as far as a factory configureation manadged , on petrol .

I know of two places that can dyno a Commando on rear wheel dyno or engine dyno, Big D in Texas and Jim Comstoct in Colorado for low and hi attitude tuning. Steve Maney wrote me his 920's @ 7200 made 100.4 rwhp.

The Late Great Sir Eddie almost got to live his dream machine land speeder his son is now taking up the cause.

sir-edward-bilton-smith-late-great-norton-twins-t11381.html

sir-eddy-rocket-t14978.html

Thanks for the replies. This is the type site I was looking for .

The engine is to be used in a well-sorted Sidecar rig. We currently run a Weslake in the 650SCPG class, but are looking into upsizing.

Regards, Joe

Joe, you might find some of the comments in this thread interesting.

commando-top-speed-t8277.html?hilit=bonneville

It's pretty long-winded, but if you go through it you'll find several good data points on Norton horsepower and speeds at Bonneville.

Ken

Matt, thanks for the reprint of the motorcyle sport article, I remember reading it back then, after replacing the mains on my 72 combat, I fitted a Boyer ignition, very cutting edge in 73. That bike got sold in 74, after a trip to Israel which included a dropped valve!

Hi folks, I'm Bill Anderson Jodar's partner in LSR. The sidecar we run has been very successful in the 500 and 650 classes. Its powered by a pushrod 540cc Weslake single. The extra 40cc is to allow us to run legally in the 650 class. Done by going from an 86 mm bore to 90 mm. We currently hold all four pushrod records in the 500 class and two in the 650 class. The best being 128.733 in the 650 fuel class (set on race gas).

The thought to go to the 750 class is because I have access to enough parts to build a 750 Commando engine. I have no experience with Commandos and what makes me nervous is the engine would be built from mostly used parts. I have heard stories of super fast Commandos and very short lived ones as well. So it is a bit confusing.

My concern is would the engine, using stock parts and some race parts, make enough power to be able to run over 130? The Wesake has been over 130 on a couple of occasions and I'd hate the thought of building a bigger engine that would run slower. The other train of thought is to find an Aisin blower and see just how fast an ancient Weslake can be made to run.

This is the wee beastie.

You sure thats low enough to the ground ?!

Sorry, we are not much used to such beasties.
Very impressive.
How does the pilot see where he is going ??
If he sat up to look, it'd slow down .

You'll need to chat to the resident engine guys here, some have already chimed in, about crack testing what you have.
And possibly discarding that central cast-iron flywheel in the crank.

With such a low bike, we'd think that a near stock good engine should be able to exceed that speed.
Providing you can gear it tall enough.

P.S. Do you have pix of this thing in flight.
It does look like the pilot would sit (up?) in the airstream, and needs at least to small screen in front, to assist the aero ?

TC Christensen's Hog Slayer is the most famous way over powered and over rev'd example of real Norton all factory numbered parts engines on nitro methane for 150 hp each @ 8000 rpm, though he told me in the rush of accelerating excitement he sometime missed shift point with rev's rising so fast it'd hit upper 8000's just fine. That was using 850 cases, cast iron flywheel, Al rods and off the shelf cam and valves and head and bearings. TC was breaking records for many many very active seasons in a row w/o ever opening the engine for anything. IIRC like 160 runs. These power plants made TC invent new type clutch and tranny that later dragsters incorporated so as usual the real weak link is the Commando drive train. There was a post here that detailed TC's engines.

In my case I lucked out to stumble on a '68 Ranger/Cheetah dedicated drag bike with a Woods or Axtell level engine I call P!! out of pure terrorized respect. I would flat walk away from the H2 Chainsaw triples of the era and no Triumph triple would even dare race after I gave it a little blip and let clutch out for a whiplash blurr leap a couple-3 bike lengths out - they'd all turn off at first opportunity. It had chopped forks and dropped frame 2" low stance so would only lift front level not wheelie and only touch front down an instant on each kill button WOT shift done at 9000 rpm where the tack had been marked by the builders so I never let it go higher than that. It ran mid 10 sec 1/4 mile on a flat slick and I could break under 11 on street tire if careful on first 3 gears throttle not to just spin in place. Front would ease down about mid way through 4th. I could not go WOT twist up till over 65-70 mph or would become instant flat tracker down the road crown. I never EVER held on in 4th long enough to see what it'd do but likely over 140. Outlaw Harley gang bikes were the only ones of that era that could or would keep up on straights which pissed me off I couldn't run away from them over 130 just neck and neck. I was a nerd with slide rule and penny loafer back then but they didn't care as that P!! was so loud and bad they adopted me but I freaked out on observing that life style in time. I was 20 yr old and did not spare the rod but it never blew up just blew my mind and others.

So do not confuse fear of Norton mistakes like Combat birthing troubles with what was being done extremely well in late 60's early 70's with basic Norton parts spiffed up here and there to suit. The thing i'd fear most would be the cast iron flywheel to swap for steel verison. Factory head kit floats valves to soon too. 750 cases can be welded up a bit too ahead of time and one of my Combat cases survived tach needle peg bounce to completely disappear for a few seconds, even after throttle finally slammed shut,ugh. Crank bent and destroyed stuff in primary melting out the alternator insides and TS case guts, cam tensioner unwrapped and oil pump stout fractured but cases fine and engine ran another 2000 miles no problem but loss of power @ 5000 rpm d/t no cam tension on spark timing and cam lobes knocked down a good bit.

I know in my heart of hearts whether I'm misleading myself or others to claim a Maney Comstock Fullauto JMS TTI Seeley is a Norton Commando or just retro looking mimic.

Rohan said:

You sure thats low enough to the ground ?!

Sorry, we are not much used to such beasties.
Very impressive.
How does the pilot see where he is going ??
If he sat up to look, it'd slow down .

You'll need to chat to the resident engine guys here, some have already chimed in, about crack testing what you have.
And possibly discarding that central cast-iron flywheel in the crank.

With such a low bike, we'd think that a near stock good engine should be able to exceed that speed.
Providing you can gear it tall enough.

P.S. Do you have pix of this thing in flight.
It does look like the pilot would sit (up?) in the airstream, and needs at least to small screen in front, to assist the aero ?

Click to expand...

I'm the "pilot". Visibility is limited but seeing is a bit overrated at Bonneville. Basically there's nothing to hit. I can't see too much forward but the view out the side is adequate. Watch for the quarter mile markers and the mile markers. Here is a short video from last year.

http://youtu.be/r5EBHbk3Ito


I have heard stores about TC using stock parts. I'll go search and see what there is to find.

Bill were you guys at the Bub this year??

Hortons Norton said:

Bill were you guys at the Bub this year??

Click to expand...

No. We go to SpeedWeek. Regretfully finances allow only one trip per year to the salt. SpeedWeek gives you a full week on the salt.

TC's details when Norton numbered parts was all there was to build with - for extra joy in rubbing Harley's noses in, for like half dozen years.

topic-t12069.html

https://www.google.com/#q=tc+christense ... er+youtube

A fascinating and eye opening read. Thank you.