400ex motor in 250r frame?

[mac_ando]

just wondering if anyone has tried it. i see alot of other swaps. but have never seen this one.

[C41Xracer]

i tried and it didnt work. the top frame rails are to low

[250Renvy]

It's a good in theory, but like anything the 4-stroke motor is too big and heavy for the stock frame. It would involve lots of hacking - your best bet would be to get a hybrid YZ426 and change it up.

When I was looking at the best motor for a trail quad, I first thought of the 300ex and started along that route then decided the Z400 would be better as there are more options available and it's a liquid cooled motor.

[jcs003]

you can find 400ex frames anywhere cheap. just go that route.

[woodsracer144]

Originally posted by mac_ando
just wondering if anyone has tried it. i see alot of other swaps. but have never seen this one.

i was thinkin that same thing!

[mac_ando]

well i've started on mine. i can make it work. i picked up an 86R ... i'll keep you all posted

[C41Xracer]

this is going to be interesting

[250Renvy]

Originally posted by mac_ando
well i've started on mine. i can make it work. i picked up an 86R ... i'll keep you all posted

I can tell you 100% that you can't make it work without lowering the lower frame rails or getting a custom gas tank made.

If you decide to mount the motor through the swingarm please let me know what you use to make it fit as the hole is bigger than the swingarm bolt.

Check my sig for my 300exr build. There are some pics of the 300 which is slightly smaller in size but similar dimensions as the 400ex. I tried the 400 and Z400 and they are bigger motors that hit the top. It just barely works with the hybrid frame, let a lone a stock frame.

If you are anywhere close to harrisburg, look up HRE - he would have some good advice.
HREATV.com

[mac_ando]

Well i think you should get your percentage meter checked or re-calibrated.. HaHa just kidding. cuz i have everything all figured out. as far as the swing arm bolt. the 400 and 250r will interchange. (same bolt!!!) . And you can't run the swingarm bolt through the motor anyway. cuz the motor won't go back that far.. the bottom frame rail that runs across under the swingarm is round, and the 1 on the 400 is flatend more. So you have to make a special rear motor mount. i made mine out of the old R mount and a piece of C channel. this rear mount alows you to sit the motor forward and down slightly. At this point the motor wasn't the issue anymore. It was the throttle cable comming up out of the carb. (you know the big elbow). so i took the cable out of the top and mounted it into the plastic side cover. and it still works perfictly. then you have the issue with the air filter tube. I had to notch & reinforce the top rail that runs across above the rear shock mount. well you get the point!! I just got all my stuff back from p/c and i'm starting the assembly.

[250Renvy]

Post pictures - start a thread then and show assembly. Show me what you did to avoid having the head hit the top frame rails and how you are going to get the gas tank to fit without getting a custom one made that clears the top of the motor as well.

I tried doing this in a stock dimension frame and it just wouldn't fit. The hybrid frame is still tight and it's got the extra inch clearance.