Author Topic: Billet Crankshafts  (Read 801 times)

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Offline kmb69

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Billet Crankshafts
« on: December 22, 2020, 08:57:11 am »
Making progress. Billet cranks ready for gear cutting.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Billet Crankshafts
« Reply #1 on: December 22, 2020, 09:57:44 am »
Looking great Leroy!

How about some background for everyone?
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline MRieck

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Re: Billet Crankshafts
« Reply #2 on: December 22, 2020, 10:16:28 am »
 The counterweights look like counterweights should look like.
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Offline kmb69

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Re: Billet Crankshafts
« Reply #3 on: December 22, 2020, 11:09:05 am »
Looking great Leroy!

How about some background for everyone?

Goal: 1 BAD mofo, gear driven, SOHC Automatic
100's of design and engineering hours invested
These cranks are designed to work in gear driven SOHC A's & K's, and gear driven DOHC's, 900 and up
Can be run with or without electric starter
Can be run with or without CB1100D rotor and stator
Straight shot oiling
Requires Hayabusa rods

« Last Edit: December 22, 2020, 11:12:03 am by kmb69 »

Offline kmb69

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Re: Billet Crankshafts
« Reply #4 on: December 22, 2020, 11:11:32 am »
The counterweights look like counterweights should look like.

I agree. One of 2 things my crank builder modified from my original design: counterweights to match my rods and pistons and straight shot oiling

Offline MRieck

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Re: Billet Crankshafts
« Reply #5 on: December 22, 2020, 12:18:09 pm »
 They are works of art brother. ;)
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Offline dragracer

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Re: Billet Crankshafts
« Reply #6 on: December 22, 2020, 12:47:37 pm »
Whats the stroke on the beauties??

Offline kmb69

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Re: Billet Crankshafts
« Reply #7 on: December 22, 2020, 01:44:26 pm »
Whats the stroke on the beauties??

Frankie, I can't tell all my secrets, LOL, but they are a little over stock. DOHC equivalents.


Offline MRieck

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Re: Billet Crankshafts
« Reply #8 on: December 22, 2020, 04:00:11 pm »
Are those rod journals larger than the mains???
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Offline bwaller

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Re: Billet Crankshafts
« Reply #9 on: December 22, 2020, 04:19:59 pm »
Wow, very very cool!

Offline dragracer

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Re: Billet Crankshafts
« Reply #10 on: December 22, 2020, 04:49:10 pm »

Lol, thanks for the answer. Very nice piece. Looking forward to seeing what you install this work of art into and viewing the results of the effort on a dragstrip. All I can do is drool and support you from the sidelines.


Whats the stroke on the beauties??

Frankie, I can't tell all my secrets, LOL, but they are a little over stock. DOHC equivalents.



Offline kmb69

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Re: Billet Crankshafts
« Reply #11 on: December 22, 2020, 05:29:27 pm »
Whats the stroke on the beauties??
Frankie, I can't tell all my secrets, LOL, but they are a little over stock. DOHC equivalents.

Lol, thanks for the answer. Very nice piece. Looking forward to seeing what you install this work of art into and viewing the results of the effort on a dragstrip. All I can do is drool and support you from the sidelines.


Not necessarily true. You may have to ride this thing. You have the experience and the gonads. I'm too old! LOL

Offline kmb69

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Re: Billet Crankshafts
« Reply #12 on: December 22, 2020, 05:48:38 pm »
Are those rod journals larger than the mains???

Very observant Sensei!

The journals are designed for 38mm Hayabusa rod bearings and rods. Pretty sure those rods are good for 200+ HP.
It only added 2.7 ounces to the total weight - 38mm vs 36mm x 21mm wide.
The FEA analysis indicated the rigidity of the crank increased significantly. Way more valuable than the cost of the weight.
The straight shot oiling also increased the rigidity significantly.


Offline dragracer

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Re: Billet Crankshafts
« Reply #13 on: December 22, 2020, 05:48:50 pm »

You've done the hard work.  I'm open  to do my part if it'll help the overall project come together. The whole SOHC and DOHC communities will benefit from your dedication.
Whats the stroke on the beauties??
Frankie, I can't tell all my secrets, LOL, but they are a little over stock. DOHC equivalents.

Lol, thanks for the answer. Very nice piece. Looking forward to seeing what you install this work of art into and viewing the results of the effort on a dragstrip. All I can do is drool and support you from the sidelines.


Not necessarily true. You may have to ride this thing. You have the experience and the gonads. I'm too old! LOL


Offline kmb69

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Re: Billet Crankshafts
« Reply #14 on: December 22, 2020, 05:51:35 pm »
Wow, very very cool!

Thank you Brent. It's been quite challenging.

Brent, I may be interested in some of your NOS parts you posted somewhere.
Please PM or email me the list if you can.

« Last Edit: December 22, 2020, 05:54:06 pm by kmb69 »

Offline scottly

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Re: Billet Crankshafts
« Reply #15 on: December 22, 2020, 09:19:26 pm »
Keith, what do you mean by "straight shot oiling"? It looks like there is a significant V shaped groove in the journals? 
Don't fix it if it ain't broke!
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Offline dragracer

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Re: Billet Crankshafts
« Reply #16 on: December 22, 2020, 09:55:01 pm »
Any idea when assembly of the power plant will begin and will you share the process with us?? What horsepower numbers are you anticipating.?? Yeah, I've got questions.  Lol. Wise choice on using  stock Busa rods. It helps keep cost down due to wide availability of both used, inexpensive parts and brand new rods

Offline kmb69

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Re: Billet Crankshafts
« Reply #17 on: December 23, 2020, 07:54:05 am »
Keith, what do you mean by "straight shot oiling"? It looks like there is a significant V shaped groove in the journals? 

Straight shot oiling is one of the latest advances in racing cranks for autos and bikes.
It is claimed to be much stronger than cross drilled oiling holes.
Pictures attached.

Offline kmb69

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Re: Billet Crankshafts
« Reply #18 on: December 23, 2020, 08:17:21 am »
Any idea when assembly of the power plant will begin and will you share the process with us?? What horsepower numbers are you anticipating.?? Yeah, I've got questions.  Lol. Wise choice on using  stock Busa rods. It helps keep cost down due to wide availability of both used, inexpensive parts and brand new rods

Frank, I am peddling as fast as I can. This is all bleeding edge stuff for me, so it's hard to timeline on a calendar.
I am taking the cranks over to Austin to cut the primary and HyVo gear teeth after the first of the year.
They then go back to California for final grinding and Ion Nitriding.

Transmissions are essentially finished except for the primary drive gear that I wanted to wait on the crank gears to insure proper backlash. Got to work out the air shifter control.
Still machining on the cases, cylinders, and heads. DOHC frames are already fitted for the SOHC engines but still need a little work on the rear suspension.

Was planning on documenting the first assembly to some extent. Horsepower? The computer calculated potential is overwhelming for my pea brain. Proof is in the pudding.

Yep, the Hayabusa rods were a no brainer for multiple reasons.


Offline bear

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Re: Billet Crankshafts
« Reply #19 on: December 23, 2020, 05:08:39 pm »
Well! You have been busy. ;D
The older I get the faster I was.

Offline kmb69

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Re: Billet Crankshafts
« Reply #20 on: December 23, 2020, 06:39:29 pm »
Well! You have been busy. ;D

Hi Brian,
It has been quite a challenge.
Cannot wait to get one assembled.

Merry Christmas!

Offline 754

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Re: Billet Crankshafts
« Reply #21 on: December 23, 2020, 08:25:00 pm »
 My GRANDPA  was Straight Shot  drilling cranks 70 years ago ... :o
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Offline scottly

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Re: Billet Crankshafts
« Reply #22 on: December 23, 2020, 08:58:34 pm »
My GRANDPA  was Straight Shot  drilling cranks 70 years ago ... :o
;D ;D
Don't fix it if it ain't broke!
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Re: Billet Crankshafts
« Reply #23 on: December 23, 2020, 09:23:28 pm »
 This is the coolest thing I've seen since Mikes billet blocks.  That's an awesome pic Frank.
No matter how many times you paint over a shadow, it's still there.

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Re: Billet Crankshafts
« Reply #24 on: December 23, 2020, 10:13:36 pm »
 I thought I had read years go Coan racing had done some torque converter work on a 750a. It seemed like they were only able to change clearances and not fin angles. If I remember correctly.
No matter how many times you paint over a shadow, it's still there.

Offline gschuld

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Re: Billet Crankshafts
« Reply #25 on: December 23, 2020, 10:22:33 pm »
Awesome😎

George

Offline 754

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Re: Billet Crankshafts
« Reply #26 on: December 23, 2020, 11:52:26 pm »
Not to take anything away from these billet cranks, they are AWESOME  pieces of work.
 Will the teeth be cut on a gear shaper  ? Are these cranks all spoken for.... it's out of my comic universe. 
 
 Btw  is the crank nitrided, then finish ground ? It's a pretty tough surface.. on my BMW I pounded out my shells badly and Journals survived... polished them up in the cases. Just wondering, as itt would be a good tough surface on  a stock crank.
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It's All part of the ADVENTURE...

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Lost quite a few CB 750's along the way

Offline kmb69

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Re: Billet Crankshafts
« Reply #27 on: December 24, 2020, 07:27:52 am »
Not to take anything away from these billet cranks, they are AWESOME  pieces of work.
 Will the teeth be cut on a gear shaper  ? Are these cranks all spoken for.... it's out of my comic universe. 
 
 Btw  is the crank nitrided, then finish ground ? It's a pretty tough surface.. on my BMW I pounded out my shells badly and Journals survived... polished them up in the cases. Just wondering, as itt would be a good tough surface on  a stock crank.

Damn Frank, never knew you were a crankshaft expert too! Came through your ancestry?
Primary and HyVo teeth will be cut on a vertical gear shaper. We had to have 8" Pitch diameter gear cutters (LARGE) made for clearance between the crank OD and the shaper spindle.
Yep, they will be Ion Nitrided, then ground and final ballanced. The base material has already been heat treated to 40 Rc.

Offline 754

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Re: Billet Crankshafts
« Reply #28 on: December 24, 2020, 10:59:49 am »
Actually I don't know much about them... and the drill pic came off instagram..
 What I was wondering, you cannot nitride a stock 750 crank, right ? As finishing would result in no bearings available ?
 What I know about nitride cranks , had to cut a key way in one for a blower snout.. tough to get through.
 And I had heard that Beemer  airhead cranks  don't get reground.. i think. .
 After hammering out a shell on mine , and being able to just give it a polish I understood a bit more how tough the nitride is.

 So the billets,  are they 4130 or 4340 alloy ? Would be much stronger than stock.. 
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

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Re: Billet Crankshafts
« Reply #29 on: December 24, 2020, 11:03:57 am »
Inquiring minds need to know............are they all spoken for?............early or late Busa, or either?
Dennis in Wisconsin
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Offline kmb69

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Re: Billet Crankshafts
« Reply #30 on: December 24, 2020, 11:32:58 am »
Actually I don't know much about them... and the drill pic came off instagram..
 What I was wondering, you cannot nitride a stock 750 crank, right ? As finishing would result in no bearings available ?
 What I know about nitride cranks , had to cut a key way in one for a blower snout.. tough to get through.
 And I had heard that Beemer  airhead cranks  don't get reground.. i think. .
 After hammering out a shell on mine , and being able to just give it a polish I understood a bit more how tough the nitride is.

 So the billets,  are they 4130 or 4340 alloy ? Would be much stronger than stock.. 

These are made from a double melted VAR 4330M. Slightly less nickel than 4340. My crank guy says it's his top choice for tough cranks. People argue this.
This material has high tensile strength, high fatigue strength, improved notch toughness and high resistance to crack propagation.
It's my understanding it also allows a deeper case depth from the nitriding.

Cannot answer your question about nitriding stock cranks.

Offline kmb69

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Re: Billet Crankshafts
« Reply #31 on: December 24, 2020, 11:40:48 am »
Inquiring minds need to know............are they all spoken for?............early or late Busa, or either?

I actually made them all for myself. They are going in a SOHC A, a SOHC K, and a DOHC. Two spares. Lots of people are asking though. We'll see.

Actually designed for the early Hayabusa rods but should work with either. The Hayabusa rods have bushed small ends so pin diameter can be adjusted as desired.

Offline madmtnmotors

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Re: Billet Crankshafts
« Reply #32 on: December 24, 2020, 12:05:26 pm »
Nice!

🤤 🤤 🤤
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Offline dragracer

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Re: Billet Crankshafts
« Reply #33 on: December 24, 2020, 02:24:24 pm »
Inquiring minds need to know............are they all spoken for?............early or late Busa, or either?

I actually made them all for myself. They are going in a SOHC A, a SOHC K, and a DOHC. Two spares. Lots of people are asking though. We'll see.



Now thats being kind of selfish isn't it? 🤣  Just kidding!! Glad you're stepping up to do something like this to keep the spirit of the SOHC legacy alive. The old heads around the world may be the only ones to appreciate what you're trying to achieve and thats okay. Often times we do things to make ourselves happy with no need for validation from others. I'm sure your overall package will result in a record setting SOHC motorcycle. 

Offline MRieck

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Re: Billet Crankshafts
« Reply #34 on: December 24, 2020, 04:13:10 pm »
Inquiring minds need to know............are they all spoken for?............early or late Busa, or either?

I actually made them all for myself.
I thought your wife had those made for you as a Christmas present. ;D
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Re: Billet Crankshafts
« Reply #35 on: December 25, 2020, 08:41:17 am »
Thanks, Keith............your knowledge is an added Christmas present ;)
Dennis in Wisconsin
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Offline kmb69

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Re: Billet Crankshafts
« Reply #36 on: December 25, 2020, 08:52:02 am »
Inquiring minds need to know............are they all spoken for?............early or late Busa, or either?

I actually made them all for myself.
I thought your wife had those made for you as a Christmas present. ;D

Well, HALF of their cost was technically her money!

Mike, EVERY DAY I wake up without a chalk line around me IS Christmas to me!

MERRY CHRISTMAS!