400ex Hybrid Ideas

[rappin_ernie]

Hey Everyone,
I have had my 400ex for a while now, and after riding a lot of quads and bikes, I have decided to stick with my 400ex to keep and build. Instead of moving up to a 450, I'd rather be unique and build my 400ex into a hybrid.
My question is, will it really be that much benefit over the 400ex engine? I currently have a 440 kit, Stage 2 Hot cam, jet kit, Full FMF exhaust and K&N. Would putting a piped yz426f motor in give me any benefit? I was also thinking of doing a 450 conversion, or converting my 400ex engine to kick start and shaving the fly wheel.
Which way does everyone think would give me the best, most torque and HP motor?
One more thing, I don't care about the fact that it is easier to just buy a 450, this is a project I really want to do.
Thanks a lot and all help is appreciated!

Mike

[Punkmaster Flex]

A 426 or 450 motor WILL show a big difference over your 440EX. First of all, your stock 450 will be more reliable and once piped and jetted, outrun your highly modified 440. Wanna go bigger? Big bore your 450 to 480 and say goodbye to every other quad.

As for the 426, I can't really tell but I heard they have a lot of potential too. Overall these 2 engines have a lot of potential to create big numbers and will be more reliable than a mega highly modified 400EX motor.

I'd go with a 2004-2005 450R motor if I were you. Keep Honda in a Honda and make it a kicker. Yeaaaaaaaaaaaaaaa!

[Wheelie]

The 400ex powerplant can be made to run with and beat most piped 450's.

[matt14c]

Originally posted by Wheelie
The 400ex powerplant can be made to run with and beat most piped 450's.

Can be made yes. Can it be as reliable or have as much left over potential NO. I would go with something liquid cooled and yes 450. Or even if your not going to be racing then try like a ktm 525 or something. You cannot have a fully built ex motor to the most extreme idea you could ever imagine even keep within eyesight of a fully built 450 motor. Plus wouldnt have to add and hope that a little fan or extra oil cooler will keep it cool and running properly. The ex was never inteded to do what people are doing with them. The 450's are.

[rappin_ernie]

I'm looking to race motocross with it. I don't think I would go with a 525. Any other suggestions? Also, anyone know where they sell the conversion kits for the 426 swaps? Thanks!

[brian76708]

i doubt there is a kit you just have to make your own motor mounts. i would do a yz426f transplant before a 450 there a lot more reliable IMO.

[rappin_ernie]

In another forum someone said they have a kit somewhere but didn't remember where, so I'm hopin someone knows a place.

[MtnEX]

Well... I still don't quite understand...

But if you must do this conversion, don't do a 450 motor.
That just makes no sense at all.
What would be the point?


So I guess I'm going to say do the 426 motor if you are stuck on 4 stroke. If not, a built 250R motor, or one of the 300cc 2 stroke bike motors would be cool.



And for the heck of it I am going to add that I don't know why anyone would recommend the older TRX450R engines. Some of my riding buddies ride the TRX's.... And I know for sure I've ridden 2005's and 2008's and the newer ones seem a lot sweeter to me. The gearing seems a little better to me (I like low) and the engines seem to rev out a lot further.

[rappin_ernie]

This is my thumper project, so I am going to stick with four stroke for the motor. I don't see why a 450 would have no point? It's still a totally different quad than the 450r. I am building an LT250R next, so I will save the two stroke engines for that:cool: . Thanks for all the help so far.

[liex21]

Go with a yzf450 motor they have been said time and time again to be the best motor for a hybrid for mx my friend has a yz426 and it is just overall better then the 400 motor except for reliability but your rarely going to beat the 400 motor in reliability anyway. So do some searching on the hybrid forum I would say buy a aftermarket production frame (walsh,leager,houser,lsr...) instead of a converted frame so you know it was done rite and throw a crf of yzf motor in it add some LT suspension and youll have one sick machine

[MtnEX]

Originally posted by rappin_ernie
This is my thumper project, so I am going to stick with four stroke for the motor. I don't see why a 450 would have no point? It's still a totally different quad than the 450r. I am building an LT250R next, so I will save the two stroke engines for that:cool: . Thanks for all the help so far.

I don't know... I don't see a 450R and 400EX/450R conversion as that different.

Yeah, the EX handles/turns better... but it's also not being pushed as hard without the 450 engine, so....

It's real hard for me to see the point of that conversion.

You gotta find a used engine... and they are not as cheap to build/rebuild as the 400... then you have to fab up the conversion... and so on.

There are just too many 450R's out there at too good of prices... ridden once or twice. Makes more sense to get one and do the suspension... as 400EX's have to be done too.

[Pipeless416]

someday i'll be doing an xr650l or r swap. i'd like to do the l because it looks pretty close to the 400 engine.. sleeper. i'd like the r because it can just be a powerhouse.

[MtnEX]

Originally posted by Pipeless416
someday i'll be doing an xr650l or r swap. i'd like to do the l because it looks pretty close to the 400 engine.. sleeper. i'd like the r because it can just be a powerhouse.

And those I see as reasonable conversions.
Especially the 650L.

But yes, the 650R would be so nice.
I've seen a few.

[Rootar]

i have a very well setup hybrid frame if your interested PM me

you can see it in this thread http://www.exriders.com/vbb/showthread.php?s=&threadid=298110&highlight=frame

thanks

[rappin_ernie]

Holy crap, that frame is intense! I'm leaning towards building my own, but how much are you asking?

[Rootar]

depends on what all you want with it... i have an intense fab. radiator for the frame, quadteck carbon fiber scoops, all the mounts....

i also have a spare crf motor that was built and ridden in 2007, has 30.6 hours on it according to the meter, full electronics, everything, (would need a pipe and carb) motor is 12.5:1, hotcams stage 2, light port and polish work, new rod, crank, valve springs and all at last rebuild, has dream pump cover, and dream oilfilter cover....

it depends on what you would want with the frame....

i sent you a PM with my phone number so you can reach me if you want.

thanks