300EX engine in 350X?

[Lomax]

after a few trips around the yard my soon to be wife somewhat enjoys my old 350x. doesnt really have enough umph to get the motor spinning though. I was thinking that after we were married that i could just find hera 200x or a 350x and install the electric starter kit but i think i would like to take it a step farther. I think that i would like to find a "well used" 350x that may be in some need or care for a cheaper price and put a 300EX motor in place of where the stock engine is or was. That would also give it Reverse which would be an added benifit. I dont know what all a conversion like this entails but i know if its been done, someone on here has surely done it. Please chime in a tell me the details so I will know what to expect
thanks
-Will

[Blown 331]

Well people put (or did put) the 350X motor in a 250X (same as 300ex) all the time. So I would say if it works one way it should work the other. I think one mount has to be changed or something like that. The only sticking point I can think of is, if the exhaust might hit the frame. A 300EX only has one exhaust pipe so it might line up with the down pipe on the 350X. I'm sure it can be made to work though. I'm sure if you come up with a 350X roller and a 300EX engine I'm sure you'll get it in there. A 400EX motor would be nice too, lots more power and you can get reverse in an 05 and up. I don't think that will fit the 350X as well though. Good luck!

[SYKO]

there is some member here who has done it, I think hes in NC or something like that, he was selling 300ex roller in classifieds for awhile

[Blown 331]

there is some member here who has done it, I think hes in NC or something like that, he was selling 300ex roller in classifieds for awhile

Good call.

http://www.3wheelerworldforums.com/s...0EX+MOTOR+350X

[Eric250R]

This swap is so easy it's almost boring. It is easier to install a 250X motor simply because you don't have to weld up a battery box. But that's pretty much it. Weld a box on the left rear of the frame and bend the back of the head pipe to the inside of the frame. As far as the one motor mount that didn't line up, I didn't even bother using it. I"ve done this 3 times, and it's way too simple.

[Merge_88]

I was interested in this swap myself, but wasnt too sure if I'd be happy with the 300ex power? I have owned a stock 300EX and it was pretty boring compared to my 85 350X I had. Does a different pipe and jetting make that big of a difference to the 300 engine. I like the idea of the electric start and reverse, but just dont know if I will be happy with lack of power. Any tips or real life experiences comparing the two engines?

[Blown 331]

I was interested in this swap myself, but wasnt too sure if I'd be happy with the 300ex power? I have owned a stock 300EX and it was pretty boring compared to my 85 350X I had. Does a different pipe and jetting make that big of a difference to the 300 engine. I like the idea of the electric start and reverse, but just dont know if I will be happy with lack of power. Any tips or real life experiences comparing the two engines?

That's why I was thinking a 400ex engine would be a lot nicer but I think it would be difficult to get it to fit.
I'm not sure if you've seen this but this conversion was done by a board member, haven't seen him around lately though. It hasn't been updated in awhile but a video has been added so I guess it worked out. I think 400EXs are one of the most under-rated bikes, especially on this site. http://miltechsolutions.tripod.com/o...x/atc440x.html

[Mosh]

This swap is so easy it's almost boring. It is easier to install a 250X motor simply because you don't have to weld up a battery box. But that's pretty much it. Weld a box on the left rear of the frame and bend the back of the head pipe to the inside of the frame. As far as the one motor mount that didn't line up, I didn't even bother using it. I"ve done this 3 times, and it's way too simple.

Yes...The 250X motor would be better...It is lighter,and just as powerful as the 300ex.
Plus the reverse is easier to use.

My friend has had his 300ex motor in the 350x for years.It was low on power obviously vs the 350x,but some porting and a cam brought the lowend right up there with a 350x.
The electric start would only be a benefit for a rider that doesnt want to kick the 250x motor over.Mounting the battery is kind of a PITA to deal with,and one more thing to fail on the trail.

[Blown 331]

You could also always bump the 300EX motor up to 350cc to help out with the power. And I think a nice and economical carb for 350cc is a stock 400ex carb.