85 250x swap w/ a 88 350???

[85chevy + honda]

I have a 1985 trx 250x and want to know if i could swap it out with a 1988 350 motor. Im mostly concerned about driveshaft size, do the 250 and 350 have the same driveshaft size? I dont want to snap it with a bigger motor. Also things like wiring harness and just plain clearance. Now i do have a lot of room in the engine bay being that its air-cooled, and motor mounts im not worried about you can make anything fit with the right tools of course. Any help would be appreciated. Thank You.

[Blue250X]

Well, I am not sure you have a 1985 250x, because they didn't make them yet. They started in 1987. And if you are talking about the 350x engine, they didnt make em in 1988..those ended in 86. But if your talking about a 1988 250x and a 85 350x, then those pretty much bolt right in.

[85chevy + honda]

No it says right on the frame of my bike its an 85 trx 250 (Born Dec. of 1984) and i know its not the utility quad. And the engine im looking to swap, the 350, is a 1988 but i dont know if was the 350x or not. I have been looking around and the 1985, 86, and 87 trx 250x are all the same bike. But anyway are the driveshafts and swingarms the same size on the 250 and the 350?

[DEAL]

I think hes talking about the utility trx250 and trx350.
the 350 is 4 wheel drive .. even if you leave the front drive out .. I don't think the motor will bolt right in.

[sportraxkid]

Originally posted by 85chevy + honda
No it says right on the frame of my bike its an 85 trx 250 (Born Dec. of 1984) and i know its not the utility quad. And the engine im looking to swap, the 350, is a 1988 but i dont know if was the 350x or not. I have been looking around and the 1985, 86, and 87 trx 250x are all the same bike. But anyway are the driveshafts and swingarms the same size on the 250 and the 350?

Your not making any since? First you say that you know its not a utility quad then ask if it has the same driveshaft? If your bike is a 250x its newer then 1985. It would also be chain driven and have a forward kickstart? You dont have a 250x you have a trx250 utility quad and I dont think the driveshaft's will line up.

[250X_project]

None of us are perfect, but you need to do better research. The Honda 250X was made 87,88,91, and 92. No more, no less. As for the 350X it is made 85 and 86 only. Both are chain driven. Until you find out what your machine even is we can't help you.

I believe you are talking about the utility TRX250 and the TRX350. Any pics? It have racks? Just trying to help..

[85chevy + honda]

actually i just got it recently, my first one, and i dont have any pics, it being 21 years old the plastics were completley shot and hacked up so i ordered new ones due in next week. i took the racks off of mine, im not really going for the utility quad thing, even tho i bought one lol, it was an amazing deal so i bought it. it had crane cams in it when i bought it, put a twin air filter on and looking to do more mods. i wish i could go bigger with the motor but eeh what r u gonna do its still fun of course. if u have any performance parts for sale or come across some i would deff. be interested. thanks.

[85chevy + honda]

Also have done research and thats one of the reasons i joined this forum, to get help because i dont know a lot i dont claim to know a lot im just asking for help. Also would anyone happen to know what motor, if any i could put in my bike, again it is a 1985 trx 250 (the utility) it is shaft driven and 2 wheel drive. Thanks.