Want to do a YZF/EX conversion, need info

[WKY400EX]

I'm wanting to do a YZF/EX conversion using a YZF426 motor. Now, I've done some searches, but I haven't found exactly what I need yet. I need to know exactly what I need to do to get the motor to fit into the frame. If you have a list, links, or anything that will help, I'd greatly appreciate it. Didn't MXBUBS do a "how-to" for the YZF conversion?:confused: Please help if you can. Thanks!

[robjohn74]

WHY?????

[WalshKFX]

here ya go man

http://exriders.com/vbb/showthread.php?s=&threadid=27275

[WKY400EX]

Originally posted by robjohn74
WHY????? With what I was going to put into my motor, I could sell it, and buy/install a YZF motor. I'd have about the same money spent, but with a much more powerful motor. That's my reasoning. Plus, I think it'd be a blast building a machine like that.:)

Thanks for the link WalshKFX. I'm looking for all of the info I can get. Much appreciated.

[WKY400EX]

Okay. I read through MXbubs' YZ/EX conversion thread and figured some more out. Thanks WalshKFX!

From what I read, besides the complete motor(obviously), I need the following: oversized radiator, oversized oil rezzy, custom motor mounts, spacers, and some various nuts/bolts/hoses/clamps, etc.

I'm sure I can get the radiator from Ebay, the nuts & bolts stuff and the supplies for the oil rezzy from www.mcmaster-carr.com and the hardware store. Now, where can I get a hold of the motor mounts, and spacer tubes? Isn't there another way of mounting the engine, besides using spacers?:confused:

I think I've got a complete motor lined up, but I'm looking for any help I can get on the other parts. Anyone?

[alberndt]

There was a guy racing the wisconsin quad series last year and smoked everyone with a YZF426.

[CTmxyfz]

What would be even nicer is that you could actually pick up a yfz frame and the motor would bolt right in it. You could go from there and have yourself 2 quads.

[WKY400EX]

I would love to get an aftermarket frame, but for now, I'm going to use the stock EX frame. Does anyone know where I can get the motor mounts and such? I believe I remember reading that a member here was going to be offering the mounts, spacers, etc. in a kit for a little over $100. Does anyone know? Thanks.

[CTmxyfz]

A yfz is a stock frame.

[WKY400EX]

Jeez, I'm an idiot.:rolleyes: At first, I was thinking you meant an aftermarket frame utilizing EX geometry & YZF motor.

The only reason I'm wanting to stay with my EX frame is that I've already got extended a-arms/swingarm/axle/shocks, etc. I just wish my EX parts would work on the YZF frame. That'd be nice.:)

[BSTURDIVANT]

Mounts are eaily made from 1/4 " aluminum plate- We use cardboard to make templates then cut and bend to fit. The engine needs to be lined up on the sprocket side and located properly up and down.

[WKY400EX]

BSTURDIVANT,
Have you done this conversion? If so, can you add any information that would be helpful? I just bought a 2002 YZF426 motor w/carb, electronics, etc. I just need to find a radiator and exhaust system. I appreciate any tips/tricks/info I can get. Thanks.

[BSTURDIVANT]

We have done the CRF450 and KTM in a 400ex frame.
The worst part for us was getting the engine far enough to the left to line up the sprockets.
Contact East Coast ATV, I think that they have done several.

[WKY400EX]

One thing I've really been debating on is the pivot bolt problem. I know you can drill out the hole in the frame, and the bushings to accept a 5/8" bolt. Or, you can have sleeves machined to take up the slack and make the stock EX bolt fit snug. In your minds, which would be the best idea? I'm kind of leaning toward the custom sleeves, so I don't have to drill my frame.

Also, anyone know the dimensions on the sleeve? I know that it should be about 3.5" long, but what about inside diameter, and outside diameter? Thanks.

[CTmxyfz]

find the tubing and cut it to the length you need it. Not too hard.

[BSTURDIVANT]

Now that the 450R is out you can use the swingarm bolt and swingarm sleeves from it!! You will have to cut sleeves to proper length and drill the frame.

[WKY400EX]

Originally posted by BSTURDIVANT
Now that the 450R is out you can use the swingarm bolt and swingarm sleeves from it!! You will have to cut sleeves to proper length and drill the frame. Have you done this with a 450R bolt & sleeves? Is it a much easier process?