I am curious?

[fmf400ex]

I was curious about how much more power do you get from a 406. I have seen people's sigs saying they have a 406. DOes this add any power, and whta would you need to do this, just piston and cam? I am just curious thats why I am asking.

[Sportrax10]

I dont think its so much as the extra 9cc's that help, but the aftermarket cam, and anything else that wakes up the ex engines potential. Just dont quote me on that.

[nojoke4stroke]

You will notice a significant power increase with a high compression 406 (anything under 11.5:1 to run pump gas)cam and rejet

[AndrewRRR]

What is a 406? Just a bored out stock sleeve 400? It's pretty rare that people will do a displacement increase that small to gain power. Usually it's just to clean up the cylinder walls from scratches or pits. I heard of a couple engine builders boring out new 250r cylinders to 265 (the max cc limit for the 250 class) but the power gain is minimal and you are immediately on your last bore. If your cylinder is ok, i'd just do the other mods, cam, piston, etc. Thats where the most power will come from.

[fmf400ex]

Ok i see, so really in the long run you might as well save a couple extra bucks and go for a 416.

[nojoke4stroke]

or better yet a 426,ive heard alot of good about the power and reliability

[Dune Surfer]

I have a 426 and it much faster than stock. It's not so much the size, It's the increase in compression that gives you gains. Sure a 426 with a 11.5:1 will be faster than a 406 with the same compression. Along the same lines a 11.5:1 stock bore piston will be much better than stock.
As for running any compression over 10.5:1 without some mix of race gas didn't work for me. I have had 10.5:1 and now 11.2:1 and both required some race gas mix.

[Castor-426ex]

i run a 426...and it hauls...
tommy has a 406...that the next bore size up from stock...i think its .40 over...i could be wrong...1mm i beleive...if that

what it does is leave room for improvement....do the 406 get a cam


then ride the hell out of it



if it blows go 416 or 440...you already got the cam...just need the piston kit and bore...ect..:D

[fmf400ex]

haha thats pretty crazy castor. that would mean a lot of shop time for the quad. :D