..300ex../..350x..??

["BLAHH"300!!]

i have heard about doing this swap from the 300ex motor to the 350x motor.in the 300's frame.....it would be a nice little stuff ..but what else would be needed to make this work..will it slide in and bolt right up ..i doubt it..but i'm askin.....why aren't there more swaps like this??

[330exracer]

i wouldn't recomend doing it. it can be pretty complicated. just geta 330 kit or 350 kit they be fater then the 350.

I have actually put a 350x motor in a 250x frame.
it doesnt fit right in, you have to ethier cut off the top rear motor mount of the frame and widen it or do like I did and cut about an inch off the motor case making it fit into the frame mount.

the frame was so close to the oli line going to the cam that I notched the frame to give it some room.

the exhaust will need a custom pipe, Powroll makes one I think.

the 350x motor is far better than the 250x/300ex,"in my opinion"
the dual exhaust head plays a part, I have seen a couple 350x heads on 300ex engines. one thing to remember, a 300ex is only 282cc and a 350x is 350.4cc

on the downside you would lose reverse and electric start, on the plus side you gain lots of power, 6th gear and a stronger right leg from kicking the beast over...........

look here for more info
http://www.powroll.com/honda_trx_250X.htm

[NJ300ex]

i believe it was quadfamily that once called fst and they said that they can modify the cases of the 300ex to fit the 350x head. This way you keep reverse and electric start but you get the power of the 350x.

just adding a 350x head alone to a 300ex will not make it as powerful as a 350x........
by the time you big bore a 300ex you could have put in the 350x and had money left, the 350x has a 68.4cc advantage over a 300ex. now if you added a big bore to a 350x engine.......wow.
but in the end, id say sell the 300 and just buy a 400EX........

[400exJOE]

type it in at yahoo (300ex, 350x, 250x, conversion) and see what you come up with. I did it already and there are a few people who have done the conversion and wrote how to do it. Pretty detailed too. I was interested in doing it b4 i bought my 400.

i just slod my ex engine for 760.00 and bought a 350x engine for 350.00 kit coasted 560.00 to do.....i cant wait to do this

["BLAHH"300!!]

not one negative post.....

thanx for the info guy's..i'm not really thinking of doing this but i have though about how much larger the motor was and wanted to hear what other's had to say about it....there is a 350x motor on e-bay...it's a little messed up but you know..a good project ya' know....
as far as reverse and electric start are concerned...i wouldn't realy miss it too much...i don't really ever use my reverse now unless i'm in a real tight situation.....i'd love that sixth gear as long as it had enugh power to pull it...and the kick start...well.....if it wassn't too much os a pain in the......then i wouldn't mind that either....."sell the 300 and buy a 400"......some of us don't have the cash kbperf man.....i'd like to do the conversion just for the satisfaction of saying i did it..ya' know....with a little help from my freinds of course..
...jabberjaw....what do you think...

also of note is, try to just get a whole 350x bike.....I used parts off the 3-wheeler like the swingarm, it is like an inch longer and can fit into the 250x plus the 350 axle is a inch or two wider. the shock is better I think to. I had stock 250r a-arms on mine and they were wider than the 250x stock.