01 wr426 rebuild

[turbogtimk4]

i have an 01 wr426 and going to rebuild it this winter. as far as motor work, im going to go with a wiesco piston, port and polish, and yz timing. any other ideas of how to get power? id like to stay away from boring it out just because of the price. thanks guys!

[Birdy426]

The price thing might not be a good reason to stay away from a big bore...when I did my 426, the bore was both oversize and out of round (ovulated?) beyond servicable limits. Lukes Racing 444 kit was about a benjamin cheaper than having my stock bore stripped and replated. As far as more power, go hot cams, JD Jet kit, and 13.5:1 on the piston. You'll love it!

[turbogtimk4]

what about a port and polish? how much would it help? is it a noticable difference?

[Birdy426]

Depends on who does it and how they go about it...porting will only address a specific part of the powerband, and usually costs you somewhere else. For example, if you increase the area to flow more air and improve top end, the charge velocity will be decreased and you will get less low end power. If you build areas up to increase charge velocity, you will get better low end to mid range, but top end will suffer. Just be sure you tell the guy with the grinder how you ride and what/where in the RPM range you're looking for. Just cleaning up the ports and polishing the exhaust/grit blasting the intake won't make a huge difference.

[maxtherat]

I would also say to add a new timing chain, especially if you do the hotcams. You'll love the added benefit of the auto decompression and the extra power almost comes second. Also, a new tensioner if it is in your budget.

[Birdy426]

I would also say to add a new timing chain, especially if you do the hotcams. You'll love the added benefit of the auto decompression and the extra power almost comes second. Also, a new tensioner if it is in your budget.

Without a doubt good advice. The tensioner isn't that much bank...

[123BigcoopDawg576]

Without a doubt good advice. The tensioner isn't that much bank...

when should the tensioner and chain be replaced? i have an 06 with 4000 miles on that is running great

[maxtherat]

It makes sense to do it when you do a top end since the cylinder is coming off anyway. The tensioner is cheap insurance at any time, but you can see how tight it is being held when you check valves.

[maxtherat]

Birdy426, I think that I recall that you have an 02. Off the subject, is your swing arm painted or is it the grained aluminum? If it is alum. do you think that a 02 swing arm will fit on an 01?

[Birdy426]

Birdy426, I think that I recall that you have an 02. Off the subject, is your swing arm painted or is it the grained aluminum? If it is alum. do you think that a 02 swing arm will fit on an 01?

Max-

No, I have an 01. The swing arm is painted with the factory paint and, quite honestly looks like crap. It is, however, an 02 swing arm, so yes, it will fit. I trashed my original swingarm (punched a hole thru that sucker just ahead of the axle block area), and picked up an 02 on e-bay cheap. You gotta change out a couple of parts, though, to make it work. The axle bolt for the rocker link (the one that goes thru the swing arm) needs to be an '02 part (the arm I bought came with it...the head is different and the 01 head won't fit in the 02 relief), and the bearings are a combination of 01 and 02 parts. If I remember right, it takes the outer races (sleeves) and needles from the 02, and the inner races of the 01 to make it work. I bought an 02 bearing and seal set from...I believe All Balls, and then just ordered the other races I needed from the TT store. If you're going this route, don't order the 01 parts until you get the arm and 02 bearing set, then see what you really need...it's been a couple of years and a lot of soil samples since I did the swap, and I'm not really 100% sure if it was the inner or outer races that were from the 01, but I know I had to order 02 bearings (the ones that came with the used arm were trash) and 1 set of 01 sleeves.

[maxtherat]

Too bad. I was hoping for a easier solution. Time to sand blast and repaint then. I sometimes ride some really nasty stuff and mine is looking pretty beat.