Best piston for 01' yz426

Hey all, Im looking to replace the piston in my 01' yz426. I was just wondering what the best one out there is? Im looking to increase power, but dont want to have to use race gas. I guess my quesiton is can I install the 13.5 to 1 wiseco and run 93 octane gas? Any help would be appreciated thanks.

I would go stock compression with wiseco. It will have a power increase just with the fresh topend and no unforseen fuel issues. Just my .02

Hey all, Im looking to replace the piston in my 01' yz426. I was just wondering what the best one out there is? Im looking to increase power, but dont want to have to use race gas. I guess my quesiton is can I install the 13.5 to 1 wiseco and run 93 octane gas? Any help would be appreciated thanks.

I'd recommend the Wiseco 13.5:1 piston. The increased bottom end and mid range power is worth the few extra bucks.

Some bikes need race fuel and others don't. I use race fuel, but for a few other reasons besides preventing spark knock. Most guys I know use pump fuel with the 13.5:1. Remember that a lot of newer thumpers come with a 13.5:1 compression piston from the factory (example: KX250F) and recommend 91 octane or higher.

While your in the motor, remember to replace the timing chain, valve springs, and valve seals. :thumbsup:

13.5:1, 444, with Hot Cams. As long as I run good quality gas, I can get along fine on 91 octane from the pump. Some times, the "independant" stations don't get the highest quality, and I've noticed that I can occasinally get a bit of death rattle on their juice. Yes, the increase in power is well worth it!

13.5:1, 444, with Hot Cams.

^^^^ The 444cc kit is my next mod! :thumbsup:

^^^^ The 444cc kit is my next mod! :thumbsup:

You'll love it! More of everything. After I installed the Hot Cams with the std bore, the motor revved a whole lot quicker...almost too quick. Te big bore kit made it less "hyper", but with the same hit, and a bunch more power across the board. I went up one tooth on the countershaft sprocket to make first gear usable again!

I just took 642mx's advice and did the wiseco 13:5:1 and it is awesome! Best thing I ever did... the low/mid increase was noticeable immediately. I run 93 octane and can definitely hear the wiseco piston more than the stocker.

I just took 642mx's advice and did the wiseco 13:5:1 and it is awesome! Best thing I ever did... the low/mid increase was noticeable immediately. I run 93 octane and can definitely hear the wiseco piston more than the stocker.

except for low\mid increase power is there any difference on top?

While your in the motor, remember to replace the timing chain, valve springs, and valve seals.

An tips on the best place to buy these from?

Most likely going to replace all that jazz when I have it apart. My friend is also gonna port and polish the head while its off. Then I plan on putting a Thunder Alley Slip on exhaust and rejetting. Should be some decent power gains.

THanks for the help with the compression/octane relationship. I think a 13.5 to 1 should be a large gain by itself.

except for low\mid increase power is there any difference on top?

I don't know about everyone else, but I didn't really see any noticeable difference on top.

As for getting the parts... try the TT Store or I like this place:

http://www.flatoutmotorcycles.com/fiche_select.asp

except for low\mid increase power is there any difference on top?

I didn't notice any difference on top, just a big boost down low.

An tips on the best place to buy these from?

Most likely going to replace all that jazz when I have it apart. My friend is also gonna port and polish the head while its off. Then I plan on putting a Thunder Alley Slip on exhaust and rejetting. Should be some decent power gains.

THanks for the help with the compression/octane relationship. I think a 13.5 to 1 should be a large gain by itself.

The regular TT store is awesome, but I've missed more than one riding weekend waiting on parts from OEM TT (which is really Generation MX).

I buy my OEM parts at http://www.crotchrocket.com

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