Well I did some searches and could not find much. I am in thought of doing a engine swap for my 400EX. I am wanting more power and speed. I figure it might cost as much to do a engine swap Vs. a 440 or 460 kit. I would have to send my motor out, due to lack of tools, and time.
So what is involved in a doing a swap? I really dont want to heat and bend my frame if I dont have to. Is there a kit where I can buy brackets for the motor and radiator? I could just a buy a new 450, but I have lots of money invested in the 400, and it would seem cheaper just to get a 450/426 motor.

What motor would be easiest to swap out? Honda 450R,,,Yamaha 450 or the 426?

Hope someone can help out on this.

 

You could sell your 400 for $3000-3500 and buy a new 05 for $5k OTD, I doubt you could do a swap for $1500, plus everything would be brand new.



Tom

 

hey there

your lucky i found this forum,cause i did the swap!
and its easier then i thought.

i have a 2003 400ex.did the 440 kit with all the rest( porting,planning,hi-comp piston,cam,valves,carb, cdi box,with wosh pipe)
anyway,the cylinder bolts where stripping and i was blowing gaskets.so i said, ***** it, I'm doing the swap!

found a 2005 450r motor for a good price and started the swap last winter.

the motor/swing-arm rod fits perfectly (there the same length) and the sprockets where aligned perfectly.

i found a 2005 frame in a scrap yard and took the motor mounts for the motor,radiator,and oil radiator. i also used the motor spacers from the 400 motor.

the 450r motor doesn't have the valve cover to frame mounts like the 400ex.so to strengthen the frame i put a tapped rod that I've tighten with nuts.

I've modified the plastic cover (the one under the gas tank) to fit the motor top (that is higher for this motor) and dropped the gas tank at the same place.

All the electrical wires for the motor hang at the same places and the coil is bolted on the 450r coil mount that i welded on the frame. the cdi box mount also was welded.

Now for the motor mount job!
Getting the motor height for the shifter, kick start and fit purpose was accomplished with a bottle jack, and the 450r mounts where bolted on the motor before welding on the frame (it was easier). for the radiator, because the 400ex frame is shorter then the 450r one, i had to shortened the rad hoses about an inch and a half.I've welded the 450r rad mounts and that was it for the rad (the fan is still there and working).Now i needed space for the oil radiator. i didn't have room left in front of the rad so i put it in front of the steering stem (the hoses do reach!).I did, eventually, put a grill for protection against branches or rocks.

for the kick start, there is room for it but you need to cut your plastic, but not much.

the rear brake light switch was connected to the main wires and the rear light wires had to be a bit modified to work (check the wiring diagram).for the front light, the connection plugs are the same as the 400ex so everything is matching perfectly.

for the exhaust pipe, i had some problems. i had to get it bent in a shop to clear the inside of the frame and had to cut some pieces also.but it wasn't a big problem.

Anyway. i don't know how to send a image of my quad so ill check this another time.

thx for reading : )




Alex.P