big bore or stroking the motor. is it worth it??

[400lag]

So is it really worth it to bore out or stroke a 400ex ive heard different things just wanted to get some other ppls opinions?:)

[slvrlakerdr08]

In my personal opinion its not worth it. But it depends on what ur going for, like if you want to keep up with 450s or be faster on the track or just more power for all round riding. I looked into it for my old 400ex but I decided it wasn't worth it because no matter what I did I would have gotten beat by a piped 450r or yfz anyway, so I just moved up too a 450r. But you would get great overall power for it, but u have to remember the 450s are gonna be lighter and liquid cooled which helps more. But its your call.

[400exstud]

Boring is cheap, stroking is not.

[Mx_523]

I hear the 416 and 426 kits are reliable. If your going to stroke it you might as well go with a 450r.

[Wheelie]

If you're racing, no. If you're looking for more power, yes. My setup has no problem hanging with the new 450's.

[400lag]

thanks for the advise

[honda460ex]

Doing all the work myself, and getting parts at wholesale, carb and everything to go with my 460, $1,600. Been amazingly dependable! No problems at all in a year or so. Raced, trail ridden, everything, and I'm running 13 to 1 compression. Beat a special edition yfz450 at a local fair drag race. I won and he had full exhaust, different cams, head work, and some carb work. So, it runs good! Just depends on how hands on you are to do the work for cost efficiency, and how you set the motor up to how well it performs on the power side. You can see my mods below.

[Toadz400]

From what I've heard it's a great power combo to stroke it to 416 and then bore it to 440, or bore it to 416 and stroke it the rest of the way (I forget which one it is). That way you get the torque of the stroker along with the high revving capabilities of the bigger bore.

[Wheelie]

It's the latter of the two, bore to a 416 then stroke to a 440.

It's a killer setup.:macho

[ohsobad_chevy]

If you are going to buy a 450r later and want a little more power right now, I would bore it to a 426, put a 11:1 compression piston in it, get a mild port job, and put one of the new stage 2 hotcams in it. That should settle you for a while. I would honestly not dump all the money in a 400ex to get it stroked. I would rather buy a 450r and work on that. Start with 40 HP, not 28...my 2 pennies. :D