Which would be better?

[trents88r]

Ok i have a question, which would be better for motocross, a 416cc kit, 426cc kit, or a 440cc kit, and would the wiseco 426 kit be trust worthy?

[Natertot426ex]

You will get a lot of answers to this question. i personally have a 426 kit in mine and it works for every type of riding I do. Go with a JE or Ross Piston kit if you do it. Also this is brought up many times on this site so there is a lot of info on it:D

[04'400ex'er]

My reccomendation would be the 426 if you want the most power possible. It wouldent be as turquey neccisarily as a 440, but would rev to the moon, could be used in stock bored sleeve, and lots mor reliable than the 440. 416's are great also, but for the most power and reliability, I would do the 426. Also, I do not believe Weisco is what It's cut out to be. Ross or JE would be a much better selection.

[3x440ex]

I would say go with the ross 416...it is more reliable and faster than the 440 unless you sink a ton of money into the 440...just my .02

[trents88r]

ok i have my mind pretty set on the 426 kit, but where can i get a JE or Ross 426 kit, and how much do they cost, and what all do they come with?

[3x440ex]

C&D sells them, just call the number at the top of this page and they will hook you up.

[04'400ex'er]

Originally posted by trents88r
ok i have my mind pretty set on the 426 kit, but where can i get a JE or Ross 426 kit, and how much do they cost, and what all do they come with? All you really need is an 89mm?? piston, rings, and to have your sleeve bored to have a 426 "kit". My reccomendation would be 11:1 Comp., a port and polish job, and a heavier rod also. You mine as well while you are in the motor. A cam wouldent hurt with a full exhaust and 39mm FCR. You'd have a HUGE gain in power.

[handsomejon]

How much is the 426 kit.

[cals400ex]

Originally posted by 04'400ex'er
All you really need is an 89mm?? piston, rings, and to have your sleeve bored to have a 426 "kit". My reccomendation would be 11:1 Comp., a port and polish job, and a heavier rod also. You mine as well while you are in the motor. A cam wouldent hurt with a full exhaust and 39mm FCR. You'd have a HUGE gain in power.

the 426 is 88mm
the 440 is 89mm


the piston, pin, and rings will cost around $120. then you will need to bore your stock sleeve out. when running a 426 you can either bore the stock sleeve to the max or just have a new sleeve put in. you will also want a cam to go with that piston for the best gains.

[trents88r]

thanks for all the info guys.

[TC426EX]

Go 426 man. I have a wiseco 426 piston in my TC motor and it has been super reliable. You dont have to get your cylinder re sleeved for the 426 either like the 440 and it revs faster and makes the same power...

[TM426]

I would use the stock sleeve Im not sure if its true but I talked to a few people that said that there are alot of bad sleeves out there including wiesco. They said when ridden hard and since the 400s are air cooled the sleeve will swell and sieze the piston.