More Power?

What do you all think of this?

http://www.ebay.com/itm/CRF450R-511CC-2009-2012-BIG-BORE-CYLINDER-HOTRODS-STROKER-CRANKSHAFT-KIT-/231154311987?pt=Motorcycles_Parts_Accessories&fits=Year%3A2009%7CModel%3ACRF450R&hash=item35d1dee333&vxp=mtr

I'm more than happy with my bike as it is now but i'm in planning stages already for what I will be doing next winter. I enjoy wrenching nearly as much as riding.

Stroker crank in these bikes is a no no. Guys have done it but they're really unreliable.

Oh ya?  The last thing I would like to do is make the bike less reliable.  Not like these don't require constant attention anyway.

Ive done one of those. It was so fast I was afraid for the guy that I built it for. His has been together now for about two years. He flogs the shit out of it, rarely changes the oil, his idea of washing the bike is leaving it in the rain.

 

The stroker crank ends up with a pretty extreme rod angle, but it doesnt seem to be a problem. Its a great lugger. I ported the head on the one I did, but I figured it'd run out of air on the top end. It didnt, and it was scary.

How long is the rod on those stroker crank's, Shawn?

How long is the rod on those stroker crank's, Shawn?

 

They're shorter, at least the one Id did was. The piston was setup for a stock compression height.

 

I did a 511 for a guy. The +3 stroker had the same deck with the 100mm piston kit. The +3 strokers work with the standard compression height so the only way they could do that would be to shorten the rod by 1.5mm. From 02-08 that would be a 104mm rod.

 

Using those numbers, it gives you a 1.54:1 rod angle, which shouldnt rev more than about 9000, but it does. Probably because of the offset cylinder.

Damn. I would think that a longer than stock rod would be better, then install a cylinder spacer and make new head mounts and tweak the exhaust a tad, re-degree-in the cam and weld the gear.

Edited by Eddie8v

Agreed, a 1.8:1 rod ratio would be better for sure. You'd need a longer cam chain too, which isnt that tough really. Add two links and your good to go. I guess if your going nuts, you can make a cam gear and only add one link. But doing a set of slots to advance or retard the gear as needed would help a bunch. Ive always wondered what retarding the cam by about 3-4 degrees would do on this engine.

I'm building that same engine now with a wide ratio transmission to put that extra power to work

I'm building that same engine now with a wide ratio transmission to put that extra power to work

Let us know watcha think, esp with that transmission, I about bought the wide ratio a few months ago. What cam you runnin?

I'm building that same engine now with a wide ratio transmission to put that extra power to work

Interested to know the Results

Let us know watcha think, esp with that transmission, I about bought the wide ratio a few months ago. What cam you runnin?

It's a webcam but I can't seem to remember the number. I also had fast heads port the head. If all goes well I'll be able to fire it up this weekend

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