Connecting Rods?

[wilkin250r]

What do you recommend for a heavy-duty connecting rod? I know the stock Honda rods are pretty good, but I'm hoping to build a hi-revving 340cc monster. Throwing that big 77mm piston up and down at 10,000 rpm will create a LOT of stress on the rod.

I'm not worried about weight, with the 340cc and powervalve I'll have plenty of low-end torque to compensate for the additional reciprocating mass. I need something strong, wieght is not an issue. But I'm having Falicon balance my crank, so I need to send them the complete rod, piston, and everything up front to properly weigh them and balance the crank accordingly.

[zedicus00]

the only thing i can suggest is talk to an engine builder like esr. or go to ******** and talk to c-leigh racing.

[papatrx]

If I were going to build something like that, I would go to a crank specialist and have him do the entire assembly. Out here in phoenix, there is a shop called crank works that does many custom cranks for the sabertooth guys and the t-rex banshee drag bikes. I just run the stock dimension hot rods on all mine.

The stock honda uses an 18mm wrist pin and a 24mm lower pin while I know some guys running 21mm wrist pin and 26mm lower pins. I think saber racing offers with their moster jug a 70mm crank with a 24mm wrist pin and a 31mm lower pin. Maybe you can buy just the rod and crank assembly from them.

What ever setup you go with you will have to check and adjust all port timings and deck height. I have a good buddy who has been building engines over 35 years and he has created his own nightmare by doing the whole process himself which has been a major learning experience for both of us. To get the port timing right the piston is now way out of the hole at TDC and he has had to get a blank dome from ESR for their big bore cool head. He has had to cut from scratch the dome and is still adjusting for squish angle, width and dome volume to get the right compression.

It seems that in the search for high performance we always take 1 step forward and 3 backward again and again...

[wilkin250r]

I've heard of crankworks, and I've heard they're good. Maybe I'll shoot an email off to Phil to see what they can do for me.

When I first started my research, crankworks and Falicon both came up. While I have no doubt that both can balance my crank for me, I also know that Falicon has additional services to increase strength and wear-resistance. Falicon has their own line of high-strength rods, but they don't have one for the 250r. If I want a heavy-duty rod, I would have to purchase it separately and send it to them along with my crank for them to install it.

[papatrx]

I have been in to crank works and had Phil do the 3mm stroker for my wife's r and his shop is top notch. My buddy has known Phil for over 2 decades and worked with him from time to time, he speakes very highly of his shop and his integrity. Phil is very familiar with 250r's with all the dune bike's out here, and definately has delt with a fair share of people that want gobbs of power.

[beerock]

one word, carillo;)

[wilkin250r]

I know about Carillo, but I didn't see a rod for the 250r...

[mikeboone]

While Carrillo has been making rods since 1964 they dont make any for 2 strokes. Currently, the only ATV rods they make are for the 400ex and Raptor.