What is the easiest motor 400EX

[HB416EX]

What is the easiest fit into a 400EX.Any info is appreciated.

[YZ400EX]

YZ 400, 426 or 450 is by far the easiest motor to mount up in the frame.. If you need any help let me know..:D

Like what all do you have to modify

[ss440ex]

Originally posted by HB416EX
What is the easiest fit into a 400EX.Any info is appreciated.

Simple...the one that came out!! LOL:D

Originally posted by EXking
Like what all do you have to modify

All i did was make front motor mounts and have 2 mounts welded on and the kicker extended and thats about it.

the radiator needs mounts made for it.

[markvette]

front mounts have to be made or can buy them from a member here. lower motor mounts, head stay mount. bushing for the motor as the hole in the motor is bigger than the pivot bolt through the swing arm, spacer for one side of swing arm between motor and swing arm, radiator mounts, custom oil tank and mounts, custom air box is best. kicker extension which can be built with stock yamaha parts no need to spend 200 bucks on a custom one. about it

Mark

[PismoLocal]

Does the yz450 bolt up just as easy?

[ss440ex]

Originally posted by PismoLocal
Does the yz450 bolt up just as easy?

Yes!!
Only differance is the lower engine mount sets aft about .400 then the yz426.

[JPhonda]

ok i hear about people putting in yz400 motors in their ex. Is this a big difference then the stock ex motor, or do people mainly do it for the liquid cooling.

[YZ400EX]

Originally posted by JPhonda
ok i hear about people putting in yz400 motors in their ex. Is this a big difference then the stock ex motor, or do people mainly do it for the liquid cooling.

HUGE difference.. undescribable difference..

[stocktires]

Originally posted by JPhonda
ok i hear about people putting in yz400 motors in their ex. Is this a big difference then the stock ex motor, or do people mainly do it for the liquid cooling.

I haven't dealt with a yzf yet, but with my hybrid the power is INSANE. The difference is HUGE. It would take thousands of dollars to get a 400ex motor to perform close to a hybrid bike motor, it's about 20 years newer technology. Liquid cooling is a plus, but not the reason.
As far as an actual yz400 motor, the difference should still be very big and worth it.

[JPhonda]

about how much more horse power does the yz400 motor have compared to the ex. Also do you guys think that a yz400 compares to a 416, i douth that it would compare to the a 440ex tho

[YZ400EX]

yz400's will smoke 416 and 440's all day.. there really is no comparison.. the best comparison with the yz400 motor is a stock yfz 450 or 450r motor.. They cant even be compared with EX motors.. really.. The stock yz400 motor came with I believe 42 HP.. I dont know if that is to the flywheel or rear wheel, but EX motor I think is like 26 hp if that.. A stock YZ400 motor will walk all over almost any EX motor unless you have ALOT of money into the motor..

[beadlesracing00]

Which member on here sells the mount kits for the YZ engine? I've been debating on building a hybrid from my current 400ex, or taking the 400 engine and having it bored and stroked to a 440 or 460. Would you guys say the hybrid or the stroker would be more cost-effective?

I plan on racing the local mx tracks, with the occasional flattrack race, and still play around in the yard from time to time, so im probably looking for a miracle in asking for lots of "reliable" power.

[JPhonda]

wow that is nuts. thats one thing that i dont get though. Why do they give the dirt bikes the stronger motors. If anything the quads should have the stronger motors because more wieght, and also it has better traction so you can use up all of the power. Dirt bikes cant use all of the power because more of it is lost in wheel spin. Another i think yamaha should get rid of the raptor 350 and make a 400cc fourwheeler to compeat with the z and the ex. If they would use the yz400 motor it would be the quad to beat.

[spec]

OK you guys say it is a huge difference over a stock 400 motor, or even a mildly upgraded one. I have started saving for a 450 because I need something that will compete against my friends 450s and have been thinking of getting into racing. How much cheaper would it be to turn my 440 into a hybrid instead of going after a 450? Or would it work out to about the same as buying a used 450? Also you guys said mounts needed to be fabricated for the radiator and oil tank and things like that, is that fairly easy for someone to do with not to much experience with fabricating things like that? Also what engine would you think I'd need to start looking for to compete well against the 450s they race these days? Would I want to just look for a yz450 right away, or would like the 426 have enough to be pretty competitive?

[stocktires]

A 426 should be plenty, actually a good bit faster than a YFZ, If you make the exhaust and intake right.
I would think for someone with not much fabrication experience it might be a bit dificult to do it the right way.
As far as money, you have to figure that out. Add everything up and see. Weight in all the factors of which would handle better, you would like better, coolness factor :cool: etc

[slowguy17]

where would de a good place 2 find a used yz400 moter

[300EXrider356]

besides ebay is there anything?

[H_W]

Originally posted by JPhonda
Another i think yamaha should get rid of the raptor 350 and make a 400cc fourwheeler to compeat with the z and the ex. If they would use the yz400 motor it would be the quad to beat.

Yes, but they have put that motor in a quad and it IS the quad to beat. It destroys the ex and the z. That motor, the yz400, became the yz426 and later became the yz450. You should be able to figure out what quad it is.