CR500 In a 400EX with a hint of 250R...

[QuicktimeRacing]

So thats my latest and greatest plan which is currently underway. I am starting with a bare 400ex Frame, a motor from an 86 CR500 and a Swingarm and misc parts from an 86 250R 3 wheeler. I got most all my parts from ebay such as control arms, knuckles, tie-rods, gas tank, headlight etc. and am kinda getting anxious to get moving on the project. The dirtbike motor is by no means a direct fit so I will have to do some mods to get it and the exhaust to fit as well as build a custom aluminum radiator lastly I will most likely have to remove my rear fenders when I kick it over due the kick starter swinging back but aside from that I think it should run like no other when I finish it up. The 250R swingarm is supposed to give me a little extra length from the 400ex arm which I assume I'll be needing with the extra power. I'm not sure anyone has made this swap yet but I'll be sure to keep you guys posted on it as I go along. Any input before I jump in head first? :devil:

[abuckley1290]

thats gonna be crazy fast! keep us posted man

[JOEX]

I belive there are some serious vibraton issues with this combinaton.......

[hotrodbelair]

are the 250 motors have counter ballencers in three wheelers like they do in the quad? if they do i would just throw that motor in there then put the 500 top end on it. cause that 500 motor is gonna vibrate like crazy.

[QuicktimeRacing]

I understand that there will be vibration due to the size of the motor but will it be unbareable? Is there that much difference in feeling the vibrations between a quad and a dirtbike? I intend to use the quad mostly for Dune trips, not much for trail riding. Is there a balance between the power to comfort level? Is it not worth it? -Trent

[eganracing]

thats a crazy idea. i would go for it if i was u just because u have all the parts already. good luck on your build.

[bansheemorphine]

sounds like this thing will be nutty i have been thinking about putting a cr 500 motor into my ex sometime keep us posted i want to see this thing when it's done. as for the vibration issues could you rubber mount the motor somehow?

[QuicktimeRacing]

I figure it will be fast enough to justify the vibrations. Beleive it or not I am doing this on a budget otherwise I wouldn't have come up with the plan. :D I would think it would be respectably quick, hopefully quicker than those stupid Banshees that would blow by me on my old 400ex.:( I'm use to giving up comfort for speed. I drive a low 12second car on the street in Tucson with no A/C, power steering and it won't idle below 1300 because of the cam and tunnelram. I figure whats one more abnoxious pain in the butt to ride toy? :blah:

[abuckley1290]

hows the project comin??

[GPracer2500]

Here's a good thread on 400EX/CR500 hybrids: http://www.exriders.com/vbb/showthread.php?s=&threadid=162504

[QuicktimeRacing]

Thanks for the link! I'm not sure it built much confidence as for the vibration concern but still alot of useful information. It's actually coming along quite well. I've began fabbing everything up slowly but surely. I'll post some pics up when I get a little farther along. As for the vibrations I will have to look into getting it balanced. I trust my welds and ability to keep bolts from backing out but every little bit helps I'm sure. I'll keep ya guys posted... -Trent

[jdboy]

For any engine info you will be needing you can goto www.cr500riders.com . This is the best place for info on the CR500 on the net. Good people! If I remember right there are a few hybrids on the board as well. A couple of quads and a 3 wheeler or two.

[ride_red666]

my friend used to have a cr500 hybrid. it was scary fast. make sure you get a LONG swingarm or it will wheelie all the time..

[flying dutchman]

if you ever want to build a 500cc 2stroke dirtbike engine into a quad you actualy should never go with the cr500 engine because of the vibrations.
but if you are sure you wanne build such a quad go with the kawasaki kx500 engine those motors are a lot more balanced so they wont vibrate as much

[rancid]

i would use a trx250r 6 speed motor with a 500cc sabertooth cylinder. more power than a cr 500 and it will be a 6 speed and no vibration issues.

[Penler]

idk if it will help but try to mount the engine like they mount harley engines, its rubber mounted and stuff so the vibration is limited, just a thought

[ride_red666]

Originally posted by Penler
idk if it will help but try to mount the engine like they mount harley engines, its rubber mounted and stuff so the vibration is limited, just a thought

ya like engine mounts in a car are rubber mounted

[QuicktimeRacing]

Originally posted by Penler
idk if it will help but try to mount the engine like they mount harley engines, its rubber mounted and stuff so the vibration is limited, just a thought

I was thinking of going with some poly leaf spring bushings or something similar. My only concern is whether or not flex in the motor mounts will cause problems with the chain in any way.

Is it worthwhile to get the motor balanced? Is this something to look into? -Trent