Dune me requested that I post the information on my crank.. well here it is!! If ya what a stroker crank with roller bearing in the "throw" here what it takes...

You need to call Glen at Falicon crank in FL and send him your crank and the piston you what to run with that crank . He will take your crank and balance to the weight of the piston so that the vibration is out of the working rpm. he will also balance the crank from side to side. He hard welds the pin hole full and redrills it for the extra stroke and for the roller pin.. He also puts in a differant shorten high performance con rod. It usally takes about 2-3 months to get one done.. you can get all of done for about 1000-1200$ mine cost me 1077.60$ with shipping back to me. but on the invoice it lists for 1216.00$.. ITS well worth the wait believe me it's very fast.. 57hp 55fp torque at 6000' elevation and it'll run 9,000-10,000rpm (NOT KIDDING)!!!

any questions??

Falicon crankshaft components, inc.
1115 old coachman rd.
clearwater, FL 33765
727-797-2468

 

hey thanks i was just looking at that[img]i/expressions/face-icon-small-smile.gif[/img]

 

Just wondering, what compression piston did you have and what is your compression ration after the added stroke???

 

I running ron woods 12.5 to 1. I think that it's about 13.5 to 1 or so! with the added stroke. But I contour the top of piston so it mit be slightly less.

 

So you're stock bore.

What stroke is it?

Did you consider doing it to your 680 or was there a cc limit for your racing?

Looks like some amazing torque.

What kind of power do you think it would have at sea-level? Do you add 2% or 4% per 1000'? I know for boiler / burner combustion we figure a 4% de-rate per 1000' ASL (above sea level). But, that's boilers. . . probably not the same.

Thanks for the info Sterling. Glad the kit worked out well for you. That would be an awesome trail bike??? I'm suprised you can rev it that hard.

 

I was running a 102mm bore but after I talked to Glen he made a good argument that with a longer stroke you would have better volumetric efficiency. So in the pikes peak race you cann't go over 700cc so i debored the cylinder and now I'm running a 100mm piston with a 88mm stroke. Have you ever heard of a square bore/stroke, that means the closer you come to the bore size is the same as the stroke the more power you will make but you loose some rpms..

The thing about big bores that they dont tell ya is that the bigger the piston the heavier it is!! and the more power it will rob from ya.. it will make more power but the percent lost to the heavy piston is greater then if you go with a smaller piston.. the other thing is that the flame travel doesn't always have time to get to the outer edges of the piston at high rpm which is a lose of power at high speeds.. when you have a longer stroke the incoming air/fuel has more time to enter the cylinder and fill it! leading to better volumetric efficiency and more power..

As for the power at sea level ??? I think it makes about mid 60's maybe 70. It's kinda scary to ride you can pull the wheels off the ground with just the throttle(no jerking on the bars)..

ooo this was a 680 (102mm) till I totally rebuilt it and made it 700 stroke with a (100mm bore)...

 

Great post!

That's a pretty impressive power package option.

You don't see many engies built like this.

True about the piston weight, burn rate, rev speed.

Even with the stroke you obviously don't have a problem with the R's!!!

 

A shorter rod hurts bore/stroke ratio. Also, a shorter rod applies more piston side load onto the cylinder...lowering reliability and power thru increased friction.

 

that is true about realibilty its a race engine! as for the increase friction maybe but a racing piston doesnt have as much of a skirt as most pistons do therefore less friction. its all a trade off.

 

so you could potentially use a stock piston too?