Commando Crankshaft Porn

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Mores The . . .

Commando Crankshaft Porn


The Lunati Pro Blower Series crankshaft gets drilled for slugs of Mallory metal to help internally balance the reciprocating assembly. The Lunati crank is whittled from 4340 steel alloy and features cross-drilled mains for improved oiling, dual keyways in the snout (to better retain the crank pulley on a blower application), 7/8” lightening holes in the #2, #3, and #4 rod journals, and .140” radii on rod and main journals to reduce chances of fatigue cracking. The Pro Series crank requires narrow, chamfered main and rod bearings; Kevin sourced them from Clevite.

PRE IGNITION , Steve . . .

Commando Crankshaft Porn


And that NITRO is Corrosive . :)

Commando Crankshaft Porn
 
This one has a Crankshaft , which may be appropriate. If you grow up . 8) :lol: :shock:

Commando Crankshaft Porn


THIS was WHY Isolastics , were Really Invented . :D

Commando Crankshaft Porn
 
Crikey, Matt..- next you`ll be pointing out what Dick Seaman was finding a handful back in `38...
 
Until something else comes along see if this one will do ya a while...

[video]http://www.youtube.com/watch?v=dNXP3TA5_tw&feature=context-vrec[/video]
 
Note how they undercut the pins (rod journals) 180 degrees in order to get a nice big filet radius; bigger than if you were to go tangent from rod journal surface to crank cheek surface (90 degrees).

We were doing this to some extent on the Commando main journal on the LH side to increase durability. Now rely on 90 degree filets and superior quality materials (billet).
 
How do machined from billet plain bearing cranks compare, metallurgically-wise - for strength/durabilty/resilience - vs cast &/or forged types?
 
@J.A.W My understanding is that once you step away from castings (cast iron, nodular iron & cast steel) you achive a big gain in durability. Somewhere on Access Norton (maybe this thread) there was reference to an article or articles contrasting and comparing billet to forged.

In context of what's reasonably achievable for our Norton twins, a good designed, fabricated and heat & surface treated billet crank is about as far as one needs to go. Other things begin to break.
 
Thanks, I gather you mean that if the steel billet is of sufficient spec metallurgical alloy quality-wise, then the old ductility/grain form issues become moot points in a Norton application?
 
Big riceburner crank .

Commando Crankshaft Porn


The Super Tenere's motor is completely new, a 1199cc parallel twin putting out 110PS at 7250rpm m of torque at 6000rpm. It runs a 270-degree crank to neutralise inertial torque and give a more direct torque feel at the throttle - much like last year's R1 with its crossplane crank.

Thrilling .
 
Been for a test thrashing then, have you, eh, Matt?[ Or is that really a new Commando crank assy?]
 
Since Matt has been posting Yamaha crank pix, perhaps it is worth mentioning that the late TZR 250s run 360`cranks, - albeit in a 90`V Twin mill..
 
J.A.W. said:
Since Matt has been posting Yamaha crank pix, perhaps it is worth mentioning that the late TZR 250s run 360`cranks, - albeit in a 90`V Twin mill..
Click to expand...

Never new that !!

I knew that the TRX 850 was a 270, so I guessed that the new super tenere was too but neat to see it. I wonder how well one of those mills would fit into a slimline featherbed ??
 
Hose in I should think . Manx pattern frames romier but I doubt if required . Be a good steam train but I consider to lightly built for 80 % Nitro and Bonneville , as Turners overly light creations accepted .

The crank there looks a bit pansy for a 24 Hour Max Continuous Output test , repeated . Please film & post if tryed ! . :) :wink:
 
Yeah, those V4s go [ & sound ] better when using 360`/0` cranks..even the...Hondas...do..
 
Reasons to offset bores from crank journal centers
To summarize, piston pin offset is the manufacturer's way of reducing stress on reciprocating parts. It permits these parts to be lighter, which results in more efficient manufacture and less power loss in the engine, as well as higher rpm. A complementary result of piston pin offset is reduced piston slap due to the more gradual shift from major to minor thrust. Make mine well done, please.
Click to expand...
http://www.motorcycleproject.com/motorc ... ffset.html more on above details
 
Flywheels come in various outside diameters, what effect does this have on crank dynamics?
 
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