Picts of offset crank pin for 5mm stroker crank & modded counter balancer

[freewheelers]

Here are some pictures for you guys of what the offset crank pin looks like and what to do to the counter balancer to clear the extra stroke.

Special note to Denroll .... That Pin is yours buddy.

http://pg.photos.yahoo.com/ph/thekesslers14141/album?.dir=96ec&.src=ph

[JTerry]

I'd think you'd loose considerable compressive strength with that counter balance flange ground down. When it's spinning at 10,000 RPM don't you think it'll through itself out of true?

[freewheelers]

I'd think you'd loose considerable compressive strength with that counter balance flange ground down. When it's spinning at 10,000 RPM don't you think it'll through itself out of true?

Point #1 The grinding is done on the center line of rotation ... which doesn't effect balance.

Point #2 The proof is in the puddin ... there is a combined mileage of over 10,000 miles on the machines that are in existance. NO reported problems.

Actually more ... as yosh has been doing it for years.

[NateTheGreat]

Yup its a regular good ole Yosh clone....

Dave you can expect a crank to do from year before year end hopefully.

[freewheelers]

Yup its a regular good ole Yosh clone....

Yes ... And No ... It looks the same ... However ... do to the heat treating process that John uses, it is literally 2x as strong as the stock or yosh pin. To that end, he is able to get the pin 21 grams lighter than the yosh pin. The result ... closer to stock primary crank balance. To finish the static primary balance, there has to be some weight added to the counter balancer side of the crank. Because of the lightened pin ... it is minimal ( 23 grams ). This is accomplished by drilling holes on the counter balancer side and replacing the metal with "HEAVY Metal" ( tungsten carbide ) to bring the crank back to a static balance.

Until the end of the year ... I'm going to hold the price of the stroker crank to $400.00 ... Including re-balancing the crank.

After the first of the year ... to re-balance the crank after stroking it will be an additional $100.00. $400.00 for the stroker mod ... $500.00 for the stroker mod with the crank re-balanced.

Anybody thinking of doing the stroker mod ... get you cranks to me before January 01, 2006 ... and get your crank balanced for FREE

[Aaron_Silidker]

Do you weld the pin in to keep it in phase?

[freewheelers]

Do you weld the pin in to keep it in phase?

NO .... Not nessary ... not recommended as warpage will occur thus making truing impossible.

[Aaron_Silidker]

How does the pin stay in phase...really tight press fit?

[Wayward Son]

its a interference fit just like every other roller bearing crank.

[rulingtheroost]

with the 5mm stroker crank what is the displacement with stock bore ,all so will the 440 kits work with this

[Wayward Son]

430 with stock bore.

94.5mm big bore + 5mm stroke is how you get 475.

[freewheelers]

94.5mm big bore + 5mm stroke is how you get 475.

which is the 440 big bore kit

[Aaron_Silidker]

I realize it is an interference fit. My question was how does it stay phased properly when the engine is running for many many miles? With a concentric pin there is no way for the pin to twist, but with an offset you have a little lever to turn the pin....unless the force of the engine running isnt enough to do that, then you can just say simple enough the interference fit is tight enough.

[Wayward Son]

its tight enough.

[freewheelers]

I realize it is an interference fit. My question was how does it stay phased properly when the engine is running for many many miles? With a concentric pin there is no way for the pin to twist, but with an offset you have a little lever to turn the pin....unless the force of the engine running isnt enough to do that, then you can just say simple enough the interference fit is tight enough.

It takes 5-10 ton of pressure to remove the pin from the throws (10,000-20,000 lbs of force ). Assuming Burned has the most powerful DRZ on the planet = 40-45 ft lbs of torque. That coupled with only a 2.5mm offset ( .0985 thousandths ) means that there is no issues of twisting the pin in the throws.

I'd bet that in order to move the pin in the throws would be in excess of 100 tons ( 200,000 lbs of force ).

Even Burned would not be able to get enough HP/ torque out of a DRZ engine to twist the pin in the throws .... In my humble opinion.

[freewheelers]

Another point to ponder .... Realize that I am reassembling the crankshaft Assembly with a 1/2 inch bolt and nuts and heavy backers. If you guys realized how much pressure can be produced ... using a 1/2 inch bolt and nut ... using a 7/8 inch hex and 18' of leverage ... It would BLOW YOUR MIND.

It takes at least 5 tons of pressure ... probably more like 10 tons of pressure to reassemble a DRZ crankshaft assembly.

I'm doing it with a 1/2 inch machine bolt and nuts ... Think about it!!

NOW ... when tightening bolts to their proper torque spec ... think about the actual force that is being applied (even with 6mm cap screws)... With that thought in mind ... there should be alot less stripped theads from here on and ever after ... I'll get off my soap box now.

[Aaron_Silidker]

Thanks, that answered my question .

[Plane Dr]

Quick point, no math. The force on the crank is way more than the 40 - 50 Ft lbs torque if that's all there was we'd be using rebar, bushings, and cotter pins.

The interference is enough in this case. Proven through testing not through math. Lots of cranks are welded. Lots aren't.

Like the bolt analogy. You would be surprised how a very small change in geometry can lead to amazing changes in loads and forces.

[Denroll]

Special note to Denroll .... That Pin is yours buddy.

Now that's what I'm talking aboot!

How many of these beasts are in existence? I think you have two out your way (your son and another?) and Burned has one, correct?

Nobody has a 480 yet, right?

Oh, and thanks for the pics. A picture is worth a thouand words and a lot of stuff just now made sense to me. I find machine work very interesting.

P.S. Give my crank some kustom graphics!?

[Neil Claydon]

It takes 5-10 ton of pressure to remove the pin from the throws (10,000-20,000 lbs of force ). Assuming Burned has the most powerful DRZ on the planet = 40-45 ft lbs of torque. That coupled with only a 2.5mm offset ( .0985 thousandths ) means that there is no issues of twisting the pin in the throws.

I'd bet that in order to move the pin in the throws would be in excess of 100 tons ( 200,000 lbs of force ).

Even Burned would not be able to get enough HP/ torque out of a DRZ engine to twist the pin in the throws .... In my humble opinion.

But is holding one side of the crank still, and then applying 101 lb/ft of torque to the other end enough to cause a problem.

Not being that good with maths, i haven't worked it out yet.

But that is a lot of leverage when multiplied by the throw of the crank.

By the way this is more aimed at the stock crank, than the stroker kit.

I don't suppose that Suzuki take as much care as you.

Neil. ??