400ex mx setup

[foxracer5464]

my question is which would be better for mx the 416 or the 426 also what compression ratio would be best

[josh31]

i have ran both. I had a 416 and then took it to a 426 when it needed rebuilt. There is more low end adn lugging power on the 426. My motor was set up with a TC MX cam, TC head porting, TC cdi, Lectron carb, lighten flywheel, advance timing key and 8 disk clutch (stockn uses 7). I had no problem riding with any of the 450's. this was in 2004, i ran the GNC's that year in 4 stroke B and ended up 6th for the year in points. I still have the same engine and am riding hare scrambles now with it. If you go 416 there is a bore left, but it all depends if you want the xtra power right away. good luck

[foxracer5464]

thanks josh is there that big of a diff. between the two

[josh31]

When I went from the 416 to the 426 it was over the winter. So it was a few months since I rode the 416, but i knew what it had. The first race i ran with the 426 was Echechonnee GNC. I noticed a very considerable gain in low end. I think also with the bigger engine, the advance timing and lighten flywheel helped with that. I was told by my engine builder, the 416 revs fast and the 440 has torque. The 426 is kinda best of both worlds. You would be satified with a 426. these just my opinions--you can do what ya want. Is it stock now?

One other thing, I had a Wiseco piston, 11:1--I think that is what it was, and I did not run a base gasket. I just used some sealant in place of the base gasket to gain compression. I used Permatex sealant, but you could use Yamabond or anything like that.

[foxracer5464]

yes as of right now the motor is stock except for the basics pipe and filter

[burcham400#39]

i agree with josh , i had a 400 with a 426 with the same piston , and i loved the power of it i kept up with and beat 450's with it , there is a diffrence i the 416 to the 426 , the 416 wasn't really impressive . if u really want to wake that 426 up when u get it done put an fcr on it

[foxracer5464]

didu mean put on one or dontput one on i was thinkin about the 04 05 450 carb i beleive its a 42mm

[burcham400#39]

that will help it , but a butterfly carb , will never do what a flatside carb will do , i had a 39mm fcr on mine and it was the best on the motor