Commando Crankshaft Porn

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If I live long enough this is the solution to need high rpm valve gear as bottom end bullet proof with no flex backed up by ring of steel backed up by cases and piston only as thick to hold a couple of rings as no wrist pin needed.

[video]http://www.youtube.com/watch?v=0H0stoFw3DY[/video]
 
Hi
Great Thread, I hope i can add to it with a bit of a mystery.

This crank is from my 920 commando engine that i swapped my broken combat engine plus cash for about 25 years ago.

I was told is was used for grass track racing and a friend suggested it was a Nourish Crank that was compatible with
Triumph engines?

Id love to know its origin, any ideas?
Commando Crankshaft Porn


Also im thinking of selling it and getting a road crank to make my life easier, would it have much value?
Many Thanks
Cliff
 
cliffran said:
Hi
Great Thread, I hope i can add to it with a bit of a mystery.

This crank is from my 920 commando engine that i swapped my broken combat engine plus cash for about 25 years ago.

I was told is was used for grass track racing and a friend suggested it was a Nourish Crank that was compatible with
Triumph engines?

Id love to know its origin, any ideas?
Commando Crankshaft Porn


Also im thinking of selling it and getting a road crank to make my life easier, would it have much value?
Many Thanks
Cliff
Click to expand...

Well mystery solved, amazingly I managed to track down Dave Nourish and showed him this crank! He only works about an hours drive from me!
Its a 1972-74 Low Inertia Weslake Crank modified to run in a commando by reducing the shaft dimensions to fit the main bearings, the con rods have also been machined thinner to fit the crank, the previous version of this crank (solid flywheel) was too heavy for grass track racing so he modified it as shown.
 
Is it the 89 stroke , or 82 , or something else .

Seems like itd be a good idea to install it . So it doesnt blow out the bottom at 8.000 rpm's , as some suggest .
 
Ok around when did Norton or Brit Iron twin racers begin to toss the cast iron flywheel for stronger steel ones?
My mental wrap on what strains the flywheels most is the internal leverage of fasteners and rod journals from the jump rope bending forces rather than the pure centrifugal sling apart aspect. BTw 8000 is not that impressive after some report of 9000 tolerant big twins. This is a see what ya can get away with subject ain't it...
 
hobot said:
Ok around when did Norton or Brit Iron twin racers begin to toss the cast iron flywheel for stronger steel ones?
Click to expand...

The first machined steel flywheels I know of for Norton twins were made in Southern California in the early '70s by Will Phizenheimer (Fitz). He talked Norton into giving him a copy of the factory blueprints for the flywheel, and duplicated it. I don't know how many he made, but it wasn't a lot. I had him make one for me in the mid '70s, of which there are some pictures somewhere in this thread. I ran into several people who made them for their own race bikes out of flat plate, with either bolted on or welded on counterweights in the late '70s and early '80s. Rob Tuluie and Ron Fraturelli are two that I remember, but there were others.

The first one-piece Commando crankshafts I recall were made by Moldex for Ron Wood, also somewhere in the late '70s or early '80s. I'm not sure when Dave Nourish started making one-piece crankshafts for Nortons, but I got my first one in '82, used, from a sidecar racer.

I'm sure there are plenty of others who did similar work, and maybe earlier. These are just the ones I know about personally.

Ken
 
cliffran said:
cliffran said:
Hi
Great Thread, I hope i can add to it with a bit of a mystery.

This crank is from my 920 commando engine that i swapped my broken combat engine plus cash for about 25 years ago.

I was told is was used for grass track racing and a friend suggested it was a Nourish Crank that was compatible with
Triumph engines?

Id love to know its origin, any ideas?
Commando Crankshaft Porn


Also im thinking of selling it and getting a road crank to make my life easier, would it have much value?
Many Thanks
Cliff
Click to expand...

Well mystery solved, amazingly I managed to track down Dave Nourish and showed him this crank! He only works about an hours drive from me!
Its a 1972-74 Low Inertia Weslake Crank modified to run in a commando by reducing the shaft dimensions to fit the main bearings, the con rods have also been machined thinner to fit the crank, the previous version of this crank (solid flywheel) was too heavy for grass track racing so he modified it as shown.
Click to expand...

Just to add to this grasstrack crankshaft when I raced Grasstrack sidecars, being a young and skint guy I had a Norton crankshaft machined to fit Triumph Cases, used Norton conrods also. It increased the capacity with its longer stroke, had to machine off 1/2 inch off the barrels, pushrods and tubes. This worked really well with the extra torque (weight of crankshaft) we also supercharged them and they held up very well.
JohnT
 
Great stories JohnT/Ken
Dave did say that the original Weslake crank wasn't competitive for grasstrack as the bike would just dig a hole in the ground and/or stall. He said it was too heavy, so he designed this low inertia version.He must have been making the original Weslake Cranks prior to 72 ken
He did also say that he didnt weld it and that someone else must have at a later stage (I guess that was so it didnt get thrown off :wink: )
It was a pleasure to meet him, lovely guy, very knowledgeable and very helpful. I must admit i drove past he place a few times before locating him.
Commando Crankshaft Porn
Commando Crankshaft Porn

There were barrels and all-sorts of interesting machinery/engine bits and pieces lying around, fascinating place, he was very busy but made time for me... legend!
 
Did he offer to show you his Manx? When I visited him back in the '80s he had a Manx that he kept in the house. I also found him a very pleasant sort. Thanks for the picture. It brings back memories. Seems like along time ago now.

Ken
 
Ken, thanks for reviewing the first Norton evolution leaving the Iron age. I would of thought it began in the late 60's d/t the P!! which I won't dare wind my Peel special too if that conveys both my sense of amazement and loss still lingering.

I think I've a cast wheel around and definitely have some slightly bent r/l cheeks and a new set of fasterners so temped to do destructive measured test with a press. But would that tell us anything useful besides evil entertainment? Maybe how much deflection before the fasterners pry the wheel apart, if the cheeks don't go first, then extrapolate by slinging G math to a bit short of that or by a shade tree feeler while running. A 500 rpm increase ya know ya can get away with is a good percentage of extra total thrust on tap in our low rpm sluggers. 1000 extra rpm would be orgasmic. Just because Norton quite we sure don't.

Maybe a 3D printed composite crank out of sapphire coated spidergoat silk with carbon fiber impregnated ceramic tweaked with a bow that straightens out to lock up the molecular grain strains and cases too...
 
hobot said:
Ken, thanks for reviewing the first Norton evolution leaving the Iron age. I would of thought it began in the late 60's d/t the P!! which I won't dare wind my Peel special too if that conveys both my sense of amazement and loss still lingering.
Click to expand...
Hi Steve,

it certainly could have been done earlier. I just posted the ones I knew about, and I didn't get into Nortons until 1971 or 1972 when I bought my first one.

Ken
 
Ok would of thought you'd heard of prior to 70's steel wheels. As my '68 P!! came out of the desert racer era I'd suspect Axtel of Woods had light steel wheels in '67.
I just can't imagine a cast iron one tolerating what the 2 yrs of wining drag racer did and then my lessor street usage the P!! lived through. These Nortons really wake up after 7 grand if they can take it and we've reports of a number of em able too. My Trixie cast wheel has been though at least two blow ups that required replacing a bent cheek so don't take her but rarely over 6000 and avoid red line now after a few trys to blow her up last year and learning handling limits.
I think if I rev limit Peel to 7500 she'll be bullet proof but then would always wonder how much more could I get away with...
 
hobot said:
Ok would of thought you'd heard of prior to 70's steel wheels. As my '68 P!! came out of the desert racer era I'd suspect Axtel of Woods had light steel wheels in '67.
I just can't imagine a cast iron one tolerating what the 2 yrs of wining drag racer did and then my lessor street usage the P!! lived through. These Nortons really wake up after 7 grand if they can take it and we've reports of a number of em able too. My Trixie cast wheel has been though at least two blow ups that required replacing a bent cheek so don't take her but rarely over 6000 and avoid red line now after a few trys to blow her up last year and learning handling limits.
I think if I rev limit Peel to 7500 she'll be bullet proof but then would always wonder how much more could I get away with...
Click to expand...

I don't think Axe or Ron had steel flywheels that early. Fitz is the one who made the steel flywheels for them, and I don't think he started making them that early. Can't be sure though, and it's too late to ask Axe.

Ken
 
Ok if you ain't heard of steel prior to 70's then them late sixties 750's racers were sure pressing their brittle cast iron but tough enough for a while.
 
Last weekends whittling.
IE, what to do with Ken Canaga's doorstop.

4340VAR steel
35mm pto shafts
1.985 rod journals
91mm stroke

Commando Crankshaft Porn


Commando Crankshaft Porn


Commando Crankshaft Porn


40 lbs down -another 20 to go. Man that's a lot of chips.
 
bwolfie said:
Has this become part of your "rebuild"?

Must be nice to have time for fun projects :lol:
Click to expand...

Yes, This will be going in my new streetbike motor.

Weekends, I play or work on my own stuff. Jim
 
bwolfie said:
Hmm, I need to work out that deal. My weekends are full of family stuff.
Click to expand...

Yeah, sometimes that happens. But last weekend I had to myself. So 24 hours worth of whittling it was.
 
comnoz said:
Great, I love porn. As long as it's dirty motorcycle parts.

Here is a 89mm crank from my old racebike.
It was the second crank built . The first one weighed 15 lbs and I could not get good track times from it. The one in the picture weighed 18 lbs. and was much better. If I put it back together again it will be 22 lbs or so. Balance factor was 65%
Commando Crankshaft Porn


And a short stroke crank from the same bike.
It weighed 15 lbs and was balanced at 65%
Commando Crankshaft Porn


And here is one for people who like large handgrips. Rev the engine and the handgrips would get about 2 inches in diameter. A few miles and your hands would crack and fall off.
It weighed 14 lbs and was balanced to rotating weight only.
Commando Crankshaft Porn


And here is the 91 mm crank ready for the new engine I am building for my bike.
It weighs 24.5 lbs. 2 lbs more than a stock crank. It is balanced to 60%.
Commando Crankshaft Porn


Commando Crankshaft Porn


And last is a custom 4 piece crank
It weighs 19.5 lbs. and was well overbalanced which was likely part of the reason it broke.
Commando Crankshaft Porn
Click to expand...

I had not seen this thread before but I just want to comment on that 24.5 lbs crank. The mass looks very large when you look at how small the shaft ends appear....they look tiny :shock:
 
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