commando camshafts

Now a Megacycle 560-D+ and JSMotorsports Norris D, .405" 296° 105° flat Norris fuel/drag competition cam. Racing springs,

Megacycle spec sheet @0.040" lift. They want $356 to ship one to me.
Norris fuel/drag competition cam. Racing springs and pistons required.
Lift 405", Duration 296*, Lobe centers 105*, Flat tappet clearance .015",
Intake open/close 43 btc/ 73 abc, Exhaust open/close 73 bbc/ 43 atc.

The reasons to try Norris D+ first is based on both engine calculators
and drama by a retired Norton shop owner and drag racer,
Dunchan Campbell. My first few months of Commando possession
in '99 was desparate to find resources to maintain. Found a shop
3 hr ride away so took off to discover piles and trailer loads
of dead Norton remains soon to be sold in bulk. I picked through
for sprockets and do dads, and studied the dragster photo's.
Fuel injected plain and on a boosted beast, with Harley gearboxes as
he said once Norton hit 100 hp zone they puke up AMC's parts onto the track.

He was depressed and slumped old man, dead pan like life fun all used up.
Having cut my motorcycle teeth on P!! dragster, thought to ask
what cam he liked. Bang his eye's lit up, he jumped off stool
in shade out in the sunshine, hollowering like a mad man
while dancing in circles slapping his arthritic knees till could hardly
breath, saying time after time, yEEEHAWW, THOSE NORTONS
SURE LOVE NORRIS D+ CAM, HOT DAM THEY LOVE NORRIS D+,
for like over a minute to calm down and sit again.
Hmm glad I asked.

About a year later called him up on parts, thought to ask him
once more, any cam you liked.... from barely hearing him,
HOT DAM THEM NORTONS SURE LOVE THEM NORRIS D+ CAMS,
on and on and on for almost a minute...
I had to hold phone away from ear, his was up dancing again
and almost dropped the phone waving it to cord limit I guess.
He passed on later that year.

OH man I want some of that for sure.

hobot

Theyd flogged the Combat Cam from the 70 P.R. , which had 30 mm Amals , tecnically , bar valve sizes , a Combats as Hot . Some consider the Std. Squish band head superior , AND the Tapered ports ( as per Mk 3 0 so with 1 5/8 intakes you match P.R. breathing , but exceed chamber ( CYlinder ) filling through
the greater density & Velocity created by the Taper or reducion in Diameter .
A set of coustom intakes that arnt kinked as the stock alloy ones are would premote velocity and uniformity , and VELOCITY and Ram Charge Effect to
Cylinder . Who am I to dissagree .

Found the Dual Pipes better TOP End , and usual flat resonce requireing considered opening up . Except from 3.500 . Never tried a lauch at those revs for
some reason .

Further to the MV / Honda controvisy . The MV did Handle , the Honda had C G & other ' issues ' . The TRIGONIC raceing Tyres dominated the 60s .
They were designed to give Lower rolling resistance ( V narrow contact patch ) UPRIGHT , which increased top speeds . This is where they were unsuitable
for 1970s gung ho brawls .
On the Transition to banked , brakeing ( HARD ) other than to steady , was a no no . Makes life intresting on entries . However , cranked over ,
the contact area is greatly incresed , allowing coarse brakeing and throttleing , if WELL over .If you wake up to it .

The PZ2s etc were the next generation of tyres for Disc Braked battles , with high adhesion in the trasition as well as upright . Im unconvinced they were initially superior running the bends . Around 1980 . Not as much rubber at full lean . And the KR Dunlop Carcases were Low Hard Sidewall .

This dump looks more intresting from here . On TV it looks to straight .

http://www.youtube.com/watch?v=PSQQL_Cjf20

<iframe width="640" height="360" src="http://www.youtube.com/embed/PSQQL_Cjf20?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

Almost starts a yearning .

acotrel said:

I use 34mm Mk2 Amal carburettors, with the ports tapered back to standard just before they open out in front of the valve. I would never open them out right down to the valve, and fit bigger valves. I think that when you do that you drop the gas speeds too much at low revs, and low revs is what commandos are about. I believe that when you build any racing motor you must choose between top end and torque. If your breathing suits top end better, you are comitted to reving the tits off the motor, and I've looked long and hard at the crankshaft and the cases in the Commando engine. They just won't cop it. A pre-unit Triumph engine, is not a better engine than the commando. If you are going to develop the commando to behave in the same way, better to start with a Nourish Weslake engine. It would be cheaper !
I get a bit of a laugh when I think about the compression ratio I am using with the methanol fuel. It is standard about 8.5 to one. However you don't need to run sky high comp ratios to get benefit, it works on latent heat of vaporisation and even at low comps, it is great. I am really impressed with the way my 2 into one exhaust works. When I made it I made a bit of judgement based on past experience with my old Triumph, the header pipe and tail pipe lengths are pretty much a fluke towards being right, but I believe the diameters are critical.

I've seen Herb Becker with Doug Mcrae's bike on Youtube. He looks like a wise old snoozer. I'm glad my thoughts on road racing might help you guys to go a bit faster. I've had a really bad upbringing, and I raced an uncompetitive four stroke twin for far too long. You don't become a good rider by riding a bad bike, and I've never subscribed to the idea that 'big is better'.

Click to expand...

This is probably as concise and sane an assesment that I have read on accessnorton as it pertains to performance enhancements for a Norton twin.

The kids here love Phillip Island. You can go extremely quickly there, but if you have a get-off, it is a biggie. I did it there four times in one day when I was a kid. I was using a drum brake with too much self-servo. It locked at about 100mph, and turned the bike into a ball of screeching metal, and I ended up with the bum out of my leathers. It used to stay on, and steer the bike off the track, so I ended up sliding up a 4 foot bank on my back, I fell in a mud puddle, and at one stage ended up dodging two inch thick tea trees. I can laugh about now, but back in 1967, it was not funny.
Phillip Island is a serious race circuit, but I'd still race there. I wouldn't ride at Bathurst, it is the same sort of stuff as the IOM, and has caught out a few of the top guys.

This is one of the reasons I never got really serious about road racing. If you were sponsored you might have no choice about whether you rode there, it would give you a bit of anxiety:

http://www.youtube.com/watch?v=mIbsSq-Xy5M