450 Plastic on 426 COMPLETE WITH PICS

I know on my 450 there was an extra bolt on the tank that needed a round spacer, so I think I'll be a couple spacers short. Maybe I can find something at Home Depot to suffice. Started phase one today. Installed a brand new AC Racing 450 subframe. I ended up grinding down the bracket on the frame to fit the subframe. Figured I'd never go back, plus it'd be a lot stronger than shaving off the aluminum of the subframe.

Started my cam install today. Not as hard as I thought it would be. The hardest part was figuring out my valve shim clearances. Never done that before. In all I probably took the darn thing apart 3 times trying to get it right. Upon my final shim measurements, I take the valve covers off and hear the dreaded "Ta-ting!" Down goes a valve clip! Oh well, had to order shims anyways so I'm in no rush! :thumbsup:

Your talking about the clip that holds the cam in the head properly? I dropped mine too but was able to retrieve it will a magnet. I even had rags stuffed down in the head so it wouldn't happen!!

Yep, that's the one. I could see it down there balancing on the bottom cog, tried fishing it out, but it was wedged in there somehow. Eventally it dropped right in. :thumbsup:

Just got my 450 tank in today, and obviously it's not a COMPLETE tank like it said it was. Do the 426 mounting brackets work with it? They bolted right up. Also, I had to order a gas cap cause obviously it didn't come with one. Anything else that may surprise me that I may need when I mount the tank up?

That is about it for the tank. You should be good to go.

When you checked your valve clearances with the new cam, did you check all the valves and re-shim them as well? Also, thanks for the specs on the bracket. They're all ready, but my bike's still at the dealer's waiting for my shims. I don't know how I got dooped into letting them fish out my valve clip and install the cam. I was way better off on my own!

Actually I checked them all (and do so periodically) but at the time I did the exhaust cam the intake valves were still in spec.

As of today, rear '03 MC is on, tank brackets are tacked on, subframe and '03 airbox are drilled and on. Still waiting for my seat and plastics from MX South, still waiting on shims (damn, why'd I let the dealer order them?!), and probably be next week until I get my DARN gas cap! In other words, I could probably test it out this weekend (if it all works out), but I don't have a friggin' gas cap! :thumbsup:

What part of the rad shrouds to you have to trim? The front plastic "fin", or the plastic "brace" behind it that lines up above the lower mounting tab? Still waiting on my shims! Should have NEVER ordered them from my dealer! Going on a WEEK AND A HALF now!

trim the plastice "brace". If you draw a line from the top outside (inside if you look at how it mounts to the bike) corner of the brace down to about the middle of the brace at the bottom and cut that off. I would recommend that you put the tank on, then bolt the shrouds to the tank then you will see exactly what needs to be trimmed off the shrouds to make them fit correctly against the 426 radiators. basically your cutting the brace at an angle from the top to the center of bottom of the brace.

You could allways go with saran wrap and a rubber band! :thumbsup:

I tried that but the rubber bands turned out to be Power Bands,,,,,,,,

Update: Almost two weeks now, no shims from my dealer. Tank is mounted and fits PERFECTLY. Subframe, now we have a little problem here. For some reason the subframe is either slightly tweaked, or manufactured poorly (AC Racing :thumbsup:). Put my airbox on and it was tweaked a bit, put on the rear fender and it was pointing off to one side a bit. COULD NOT line up the brackets on my new SDG seat with the subframe! Spent about 4 hours trying to figure out &%$#@!! Finally took it all apart, started tweaking the subframe and got it to where I can just mount the seat and barely line up the side panels. If it weren't for the subframe, I think the panels and seat would be as good as the tank (thanks Satch). Also, my lower exhaust mount does not line up with the subframe tab, but I got it to line up with the mount near the seat. You guys experience anything like this during install? The bike looks AWESOME, but these few quirks really kind of dampened my whole project. I probably would have been better off with a OEM subframe. Did your exhaust mount up to the subframe as well?

If one of you guys has a 00 -02 sub frame for sale shoot me a PM with the price.


did not have that kind of problem with my subframe. Are you sure they didnt send you a 426 or YZ250 (2-smoke) subframe??

Tad....check your PM's

Some stuff I just aquired. Perfect starting point for the 450 Conversion.

YZ450 Parts for sale

It's an AC racing YZF 450 subframe. I don't think a 250 subframe would fit this close. All the airbox mounting tabs line up, but when I mount the fender, it's just pointing off to one side, and the ends of the subframe look off set against the rear of the fender. You can't really tell unless you look good. The bottom exhaust mounting tab doesn't line up as well. Did your 426 exhaust mount up perfectly?

If you find a cheap 450 subframe, let me know!

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