From 406 to 426?

[trophdog]

I am currently running a 406 11:1 comp. w/TC Cam 924 MX, port and polished head, open airbox w/uni filter and a slip on pro circuit T4. Would I notice a big difference if I installed a 426 piston with 11:1 comp? And where do you think I would notice it?(Bottom end, Top end, or all around)

[fastkid400]

i wouldnt go to a 426, its unreliable and as big as a bore u can do on a stock sleeve. i suggest a 416, bigger the bore, more top end, more compression and stroke, is low end with that set up it would rip!

[cals400ex]

i don't think i would do just a piston swap. if you want more power, i would look elsewhere. i went from a 406 to a 426 and the difference isn't huge. my bike did run better but i added several mods to it while it was apart. i would make sure your gearing is good. i ran 15/36 and it was much much slower with this gearing than stock when you hit 4th and 5th gear. a mile down the road it may pay off, but until then it was much slower.

[Giz400ex]

I also did the 406 to 426 and I've noticed more torque, not a huge gain but enough to feel it! If thats something you want to do, go for it!! I'm happy I did:D

[Florida400EX]

The gain you guys may be noticing is the fresh bore. Your quad will always have more power then before on a new fresh topend.

[trophdog]

The 406 I have in right now only has about 5 hours on it. As for gearing I am running 14/38 sometimes 14/39. If the 426 doesnt make a big difference Im not going to waste my money.

:devil: I MUST HAVE MORE POWER:devil:

[trophdog]

Has anyone had personal experience with a 426 cracking a stock sleeve, or is it all just hear say? I assume thats what people mean by a 426 being unreliable.

[Giz400ex]

Nothing has happened yet:eek2: :D

[torqen2k1]

people or over reacting. the sleeve is not that thin as people say. If you do the 426 (go for it) just make sure your jetted right and get some air scoops to keep the temp down. In the future you can do a bigger oil cooler.

[mojoe2878]

Originally posted by trophdog
The 406 I have in right now only has about 5 hours on it. As for gearing I am running 14/38 sometimes 14/39. If the 426 doesnt make a big difference Im not going to waste my money.

:devil: I MUST HAVE MORE POWER:devil:
then go to a 440 or stroke it to a 465:devil:

[DaleJrFan]

i know a couple of people who have gone with the 426 and they have yet to have any probs. i am going to do it in a couple of weeks though i am going all the way with lrd full system exaust,39mm carb and larger oil tank. my buddy has had the same set-up and his quad has so much top end and has no probs in the dunes compared to mine stock. i say go for it!

[cals400ex]

i haven't had any problems with mine 426 either. i do run an aftermarket sleeve too. if your looking for huge gains in power, go with a stroker i guess. my 426 isn't quicker from being a fresh bore. i only had around 5 tanks of gas thru the 406 when i rebuilt it. i could still clearly see the cut marks in the sleeve from when they bored it. it was smooth of course from the rings filing them down though.