Can I use a used connecting rod?
 

I need a connecting rod for my 07 450 and am having a hard time swallowing the $800 something for a crank. Ive found a couple of used 03 400 crankshafts that have the same con rod. Can you press them apart and still use the pin, bearing and rod? Assuming the whole crank assembly wont work.

Sure, why not? If it wasn't a rod bearing failure or damaged rod that made you replace the set in the first place, go for it. I'd replace the pin and bearing though ... you're already there and the cost to do it now is minimal compared to splitting the cases and pressing the crank again later.

If you can get the dimensions of the rod you could check with Carillo and see if it might match up with another one that they carry.

Thats the problem, it is a big end bearing failure. If I buy this other crank, what are the chances that it can be pressed apart without ruining the pin and bearing? I really only need the two halves of my original crank, and the pin,bearing and rod off of the other. Apparently, I cant buy just a pin and bearing or conrod, I have to buy the whole crank assembly.

I'm sure there will be some dissent to this answer, but if you can get a used rod from a 400, and get it cheap, you can do it. You can press it apart without damaging anything. As long as the 400 rod is in good shape to begin with, you're in business.

While it's not ideal to reuse parts, it is the only way lots of people around the world can have any fun at all.

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So is this something I should try myself? I know my way around a wrench and have a hydraulic press, have put hundreds of car wheel bearings in, I'm just leery about balance. My first thought would be to build a jig to hold the crank so the halves don't rotate. Is this the concern with balance or is there more to it?

I dont know the exact purpose but there is a balance/countershaft that runs the waterpump

I would contact Andrew Cooksey of Cooksey cranks. He may be able to rebuild a GG crank and balance it better than stock

http://www.cookseycrank.com/

Unless you plan to machine/drill/grind the crank wheels, the balance will be what the balance will be. What you're describing is truing the crank - essentially making sure the end shafts are co-axial and the crank cheeks are parallel. Run-out is the measure of how well you've done on the job of reassembly.

Getting everything lined up before pressing the assembly together is very important. You can try to manipulate the crank after its together but that can be medieval undertaking involving big brass hammers, clamps, and prybars.

I think I'm going to give this a try, I will definitely take it to a local engine shop when im done to check the axial and radial?runout before I install. Thanks for all the advise and I'll keep you posted with how I make out.

We rebuild a lot of single cyl. crankshafts. We use a jig that lines up the two halves but even with the jig you still have to do a little brass hammer work to get them to true up. Make sure you measure the width of the crank before you pull it apart. Good luck with trying to get the crank apart. I can usually get the two stroke ones apart with the press but the big 4-stroke ones are a bitch. I usually end up cutting them apart with a chop saw but you won't have that option if you need to save the rod and pin. If you come up with a good way of getting the crank apart without damaging the rod and pin I would like to here about it. Good luck!