Who says Nortons can't Wheelie?

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jseng1

jseng1

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Mike Harding just sent me this action vid and dyno sheet of his 85 HP 920cc race bike.

Who says Nortons can't Wheelie?


 
Too subtle and brief for me, but Thanks anyway...
Which one is Harding?
 
This clip showing a Commando wheelie - not so brief for you Mr Rick
(I know it's been previously posted but it's still good)

 
About 7 seconds in there is a guy who pulls a wheelie and takes off as the leader of the pack. I'm guessing that's him. Mostly white or light colored if that helps.
 
If the bike's centre of gravity is in the right place for getting around high speed corners fast, it should spin the rear wheel before lifting the front. A lot of guys tolerate that airy feeling in corners which causes them to go a bit slower. Just because a bike wheelies, that does not make it a winner. Most race circuits have corners making up at least half the distance. If your bike has not got the legs, you can get beaten at the ends of the straights. But if you can corner faster, it is not such a problem. Sometimes all it takes to get a bike handling well is to move the motor forward one inch.
 
That’s a scene from that great Aussie icon, the movie Stone.
Midnight & Stone, racing in the early stages of the movie.
 
jseng1 said:
Mike Harding just sent me this action vid and dyno sheet of his 85 HP 920cc race bike.
Click to expand...

Jim,

This _is_ an impressive torque graph. I am excited! Did you post engine specs in another thread?
Do you by chance have a graph for a tuned big-bore shortstroke, either 77, 81 or 83mm bore? I am eager to compare the graphs with torque graphs for stock engines which I posted some time ago.

-Knut
 
Can someone explain that dyno graph ?

As i understand it, a dyno measures torque and then applies a formula to work out the power (torque X revs / 5252).

If that is true the graph above shows around 60 torques at 4750 rpm. 60 x 4750 = 285000 / 5252 = 54.26 bhp. how come the dyno has worked it out at 84 bhp.

Also if the same is applied to 7000 rpm then you get around 96 bhp not the 65 shown on the graph. I am confused (which happens a lot)
 
Are you mixing up the torque and BHP lines?

Also, note the BHP and torque axis’ are not of the same value.
 
73.5 ft*lbf * 4700 rpm/5252 [ft*lbf/min/hp] = 65.8 hp which is in good agreement with the graph.

In physical units: 73.5 ft*lbf*4700*2*PI/(60*sec) / (550 ft*lbs/(sec*hp) = 65.8

550 ft*lbs/sec = 1 hp as per definition.

-Knut
 
Last edited:
Fast Eddie said:
Are you mixing up the torque and BHP lines?

Also, note the BHP and torque axis’ are not of the same value.
Click to expand...

Thats it, it all make sense now, I am used to seeing the torque line under the power one. told you i get confused a lot :)
 
The impressive thing is that he is not trying to wheelie the bike and it looks like he reacted by rolling off the throttle immediately rather than go all the way over.

The dyno graph shows the peak torque at around 4500RPM - probably because Mike is using long intake manifolds - longer than I would think is ideal. Its 11-3/8" from the head to the end of the velos (about 14-1/2" from the valve). At that length they should be boosting the low end. I would run them at 10-1/2" from the head as Ron Wood and Leo Goff, myself and a few others used to do. He's looking for a little more top end and might get it with a 10-1/2" length intake tract from the head. He's going to experiment on the dyno soon.

I don't know much about the eng build other than he has my lightweight pistons and longer rods, the new JS2 cam. Stage 3 Maney head, 1-5/8" ex headers.

Who says Nortons can't Wheelie?


see the link that cliffa posted for more info about this amazing racer.

https://www.accessnorton.com/NortonCommando/74-space-frame-jpn-replica-pile-of-tubes.16177/
 
I have found that getting the gearing right with the Commando motor is very deceptive when you are using the heavy crank. If the over-all gearing was high enough to have you still accelerating at the ends of the straights, you would probably not lift the front or spin the rear wheel at the start of a race - unless you had a very low first gear. Racing without a close ratio gearbox is a futile exercise.
 
Had an 850 Commando in near stock trim that would lift the front wheel with a mere roll on of the throttle in third gear. Really not such a big deal............................with a Drouin Supercharger and 10 psig boost.;)
 
When the Japanese two-strokes arrived in the 1960s wheelies were common, especially at the start of races and coming out of corners. But we found that while the bike was doing the wheelie, it's acceleration in the forward direction was slower. However getting an unsupercharged Commando to wheelie is still impressive, but a waste of time during a race.
 
Dances with Shrapnel said:
Had an 850 Commando in near stock trim that would lift the front wheel with a mere roll on of the throttle in third gear. Really not such a big deal............................with a Drouin Supercharger and 10 psig boost.;)
Click to expand...

How long did it stay together?
 
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