400ex RM250 hybrid any tips?

[711stretfighter]

Here's what I have a 400ex with alba arms, old pep shocks, rpm swinger with the carrier and sxle, alba +2 arms, yz426 radiator, and electrics. I got it on the cheap as a roller. It previously had a yz426 in it so the radiator and mounts are all there. The motor had blown in it and it had been sitting for 5 years with no motor in it. For the donor I have a RM250 that I can rape. I've got pretty much everything planned out.
1 Spacers for the swingarm pivot.
2 Fab front motor mounts to easy
3 Cut and re-weld the lower motor mount
4. Fab top motor mount.
5. Airbox

Here's my number 1 question: What pipe should I use?

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0615.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0604.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0606.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0614.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0830.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0826.jpg

[ytman]

It looks like your first version of pipe would be a combination of the RM pipe and maybe an aftermarket R. With the radiator behind the vert. frame tubes you'll have to snake back and forth in front of the motor like on the bike. The bike's pipe looks like it might drop down too low. The pipe could be the most fun ( did I say fun ) part of the whole thing. It looks like you have it all planned out. Good luck. Lots of pics.

[JOHNDOE83]

Looks sweet, Im doing a cr250r swap in a 400ex right now also!!!

Just to give you some insight on my cituation, I had to make a bushing for the swinger bolt so it would fit snug in the cr motor. I used a 400ex swinger bushing and had it turned down at a cnc shop.

I was able to make the mounts for the front of the motor and under the motor, I made them outa 3/16 steel plate from Lowes.

The top mount will need to be fabbed and welded or made to be bolt on.

The kick start has to be extended from the shaft outward 3in.

The hardest part in my opinion is gonna be getting a pipe to fit, I was gonna use a out of frame trx250r style pipe but wound up buying a ftz inframe drag pipe, Now i just gotta make it fit my CR motor. It will be here on monday!

For your build I would use a LT250r style pipe! In or out of frame depending on your riding style.

Also making sure the sprokets line up may be tricky, I did alot of grinding and test fitting to get it were it is now, I had to shim my front sproket 1/16th of a inch for it to fit the way it is now. I may go back and grind my swinger a lil to make up for it.

This is gonna be sweet, 2 hybrid 400ex 2 stroke swaps at the same time!!!

In the 400ex section I have a thread with a few pics in it, i will be updating it later today.

[711stretfighter]

The pipe does hang to low to fit in the frame with the crossmember there. I can tell just by eyeballing it. Good eye man. I think that I will cut the stock pipe up and weld it back together to snake under the radiator and back 250r style. Or measure the cone diameter and length then fab a complete new one up. There's also a shop in Tulsa (3 hour drive) that can do custom pipes so that's another option I found after searching for a while. It's the most expensive but probably the best. I'll fart around with it and see what I come up with.

Awesome idea using the swingarm spacers my neighbor has some extra 400ex ones laying around. I was going to just have a machine shop make some up once I got all my measurements for alignment and the diameter of the swingarm bolt from the rm.

For the upper motor mount my plan is to just use some pipe, weld some thick caps on it and tap it or use nut certs so I can bolt it in.

I've seen a few cr250 hybrids but never an rm so we'll see how this one turns out. I'm a suzuki guy for some reason but I've had my share of honda's in the past.

[711stretfighter]

Just read your thread John, looks good so far. I will grind my swinger down if I need to instead of spacing out the countershaft sprocket. I still have my other quad to ride so I won't have to worry about down time so much. I do want to get caught up to you though lol. The good thing is I only have half days at work from now till the 3rd of Jan so plenty of time to mess around.

[audioworks04]

Looks like a good start, as with any hybrid build it wont be easy, but Im sure you know that already. I would pick up the cheapest R and LT pipe you can find and along with that rm pipe im sure with some cutting and welding you can make something work, just remember not to change it too much. Looks like the radiator might need moved to work with the pipe better. My biggest question is why does it have z400 plastics?

[711stretfighter]

Yeah I think I can get the pipe to fit without cutting it. Just making a bend or two a tad bit sharper. I like the ltz400 seat better then the ex. I also didn't get any plastics with it and I have the extra Z400 stuff laying around from my Z build. LOL it's what I have to work with.

[711stretfighter]

I am gonna have to cut the pipe but I can make it work :)

Well I started today, WOO HOO.. First problem is that the 400ex axle pivot bolt (15mm OD) is 2mm smaller then the RM250 swingarm pivot bolt (17mm OD). That means the engine will not stay straight or stay steady on the swingarm bolt. I had to make a bushing. I went to the machine shop and they wouldn't make me one. So darn I thought off to Home Depot and Lowes to figure something out. Well home depot was a no go. Went next door to lowes and found a copper pipe that I eyeballed and it looked close with in a 1mm or so. But darn I forgot my digital calipers. So I bought it anyways and took it home. It was the perfect thickness to take up the space between the 400ex pivot bolt and RM250 cases but it was to 1mm to big in diameter. To easy. Here's the steps.
Video showing play between 400ex pivot and rm cases
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/th_Video0093.jpg

Supplies
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0864.jpg

1. Cut to length needed.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0866.jpg

2. Used a square and scribed a straight line down the center. Then I cut a 1mm wide cut along that line with a dremel and filed it until when I squeeze it on the pivot bolt it's snug.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0867.jpg

3. Cut into two pieces so that I can split the cases without removing it.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0868.jpg

4. Placed it on the 400ex pivot bolt and squeezed it with vise grips then gave it some love with the hammer. Slid in perfectly.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0869.jpg

End Result:
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/th_Video0095.jpg

Got the motor test fitted and to measure the chain alignment. I'm 8mm off on lining up the sprockets. So tomorrow I will cut the swingarm on the chain side to get it in line then cut the spacers and its on to motor mounts.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0870.jpg

[711stretfighter]

Taking my time but motor mounts are done. The pipe is taking a lot of time to get right. I tried going behind the radiator but it wasn't going to work, scratch version 1.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0898.jpg

Version 2 I made my own head pipe but I measured and went back to fab it in the morning. Well I fudged the length. Anyways it fit but not the way I wanted.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0929.jpg

I start version 3 tomorrow night, I think I got it this time :)

[03trx400]

3 of these going on! and all different motors which is pretty interesting..does anyone know how fast they are compared to the new big bores and 450's?

[JOHNDOE83]

looking GOOD!

I like what you did with the swinger bushing, it sucks that you couldnt get a shop to turn down the bushing, as soon as someone mentions custom atv project most people turn a cold shoulder thinking they dont want to be held liable.

I have the same problem trying to get a mid pipe made, everywhere I go they refer me to a motorcycle parts place. I try to tell them this is custom it has to be made, they say we dont sell motorcycle parts....im like WTF.

[711stretfighter]

Got the pipe tacked together the way I want it now. Just have to bend some tube for the silencer and do the pipe mounts. Then the pipes done. It splits in the middle so that it's easy to get on and off.

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0950.jpg

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0949.jpg

[711stretfighter]

Finished the pipe and silencer mounts as well as extended the kickstart to clear the frame. I cut the kickstart shaft right before it goes into the cases and welded a stanley 14mm 3/8dr socket back in between them. I used the socket because it was almost the same diameter as the shaft just .20mm smaller so I could fit the clutch cover over it.

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0955.jpg

The shaft with the socket welded in and excess weld filed down.
http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo0954.jpg

a video of the extension installed.

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/th_Video0124.jpg (http://s95.photobucket.com/albums/l150/kissmybutt_02/Technical/?action=view&current=Video0124.mp4)

[711stretfighter]

Fired up for the first time. Now I have to take it all apart again and paint the welds. Also finish up the little nik-nack stuff. This is my first attempt at a hybrid and I'm shocked how good it's turning out.

http://www.youtube.com/watch?v=X635yI7Jnv0

[JOHNDOE83]

Sweet!

Im glad these projects are working out good so far, I hope yours rides as good as mine did on your first test ride. I actually think the CR motor is faster in the EX frame then it was in the bike frame, I hope you'll have the same results with the RM motor!

[711stretfighter]

Taking it out for the first test ride today. Hope it goes well.

http://i95.photobucket.com/albums/l150/kissmybutt_02/Technical/Photo1019.jpg