Got a 250x project, what aftermarket parts fit?

[Supergumby5000]

Me and my buddy just got a 1991 (we think) 250x for $100, and we're going to attempt to do a complete rebuilt on it.

We arent extremely experienced in this kind of work, but i figure as long as there isnt any major custom fabrication, this shouldnt be too hard.

I am mainly looking for info regarding on what parts will fit this bike, as in when looking for aftermarket stuff, what models of atv parts will fit? From the sub-forum, im guessing anything on a trx300ex, 300x, or 250x will bolt on?

We'll be using the stock frame, and pretty much replacing everything else.

What engine blocks will bolt in? or fit with minor modification? The bigger the engine, the better :)

Are there extended a-arms and swingarms that will fit? Im looking to make it 2" or so wider and 1-2" longer.

Which model plastics will fit? Ive seen a few 250x's with different model plastics on em, and i dont want to use the basic maeir 250x plastics.

any info would be great on this topic, as well as any pointers you experts out there might have!

[QuadCobbler]

If you look in the “all kinds of 300ex info" you will find allot of info on your build. Some mods I can think of are. Swing arms (250r, 400ex +2) 450r +2 or+3), (350x atc +1.5 to +2) I think all but the atc you will need to weld a mount on the frame for the pro link and you will need the bearing carrier for the swing arm. and you would need a 250r rear shock. I am prety sure all the axles are about 2" wider than a stock 250x axle. The 350x mite be a little less. Front shocks you can use with a relocation bracket are 400ex, ltz400, trx 450r, trx 250r, I am sure there are others you would need to measure the top mount width on others, and I think the ltz 400 shocks are 1" longer. Plastics, you can use the new Maier 450r style 300ex plastics or you could make new mounts for 400ex plastics. Motors, you can get a kit to install a 350x atc motor, old school hybrid, or you could go with a crf250 motor, but you would probably have to fab all of the mounts. The 350x kit you can buy on line. A-arms, you can use 400ex, or 250r with 400ex length shocks and relocation bracket and ty rods, about +2 per side. The lower 450r a-arm is wider at the frame mount and will not work unless you make new frame mounts. If I can think of any thing else usfull I will let you know.

[Supergumby5000]

Originally posted by QuadCobbler
If you look in the “all kinds of 300ex info" you will find allot of info on your build. Some mods I can think of are. Swing arms (250r, 400ex +2) 450r +2 or+3), (350x atc +1.5 to +2) I think all but the atc you will need to weld a mount on the frame for the pro link and you will need the bearing carrier for the swing arm. and you would need a 250r rear shock. I am prety sure all the axles are about 2" wider than a stock 250x axle. The 350x mite be a little less. Front shocks you can use with a relocation bracket are 400ex, ltz400, trx 450r, trx 250r, I am sure there are others you would need to measure the top mount width on others, and I think the ltz 400 shocks are 1" longer. Plastics, you can use the new Maier 450r style 300ex plastics or you could make new mounts for 400ex plastics. Motors, you can get a kit to install a 350x atc motor, old school hybrid, or you could go with a crf250 motor, but you would probably have to fab all of the mounts. The 350x kit you can buy on line. A-arms, you can use 400ex, or 250r with 400ex length shocks and relocation bracket and ty rods, about +2 per side. The lower 450r a-arm is wider at the frame mount and will not work unless you make new frame mounts. If I can think of any thing else usfull I will let you know.

awesome information, just the post i needed.

Sounds like i'll be using 450R style plastics, 400ex A-arms/shocks/swingarm

Any idea on how the plastics will line up with the 250x seat?


Oh, and i got some good news on the 4 wheeler today. Its been in my heated garage today for two days, so i thought i would try to start it for sh*ts and giggles.

Started up on the third kick :D We didnt think it ran.

So, we'll probably just get the 250x motor rebuilt and bored.

[QuadCobbler]

I belive the seat should mount right up to the plastics; direct replacement. As far as the 250x engine, it is a prety good engine to start with. Sence it is a kick start you can go with a high comp piston and some head work and not have to worry about the starter wimpin out on you. and the short stroke will give you more top end than a 300ex.