trx250 rear swap for 250sx

[obijuan]

So I have found several incomplete units and parts available. Having trouble finding this locally actually. Didnt think it would be thjs difficult. I am putting this on my 85 250sx.

1986 trx250 rear suspension parts all look very similar but im sure something just will make it a little more difficult than it seems.

What is the bare minimum parts interchange from these two? 85 250sx and 86 trx250.
I know swingarm, driveshaft and rear diff gears are different. Also the real axle shaft is supposedly different as well.

Is there a resource for superceding part numbers? Interchangeability guide where I can find this?
Or spoonfeed me pretty please? Also finding good descriptive pics of these trx parts is tough.

Any information will be appreciated and reciprocated.

[TheRealFatShady]

I was going to just use a trx swingarm and driveshaft with my stock SX rear end. However, I ended up getting a full quad for parts, so I never did.

The swingarm doesn't mount directly to the axle/final drive housing, I had to cut mine and bend it to mount it up, and I never went back to re-enforce it. The driveshaft looked fine but the part which gets mounted by four bolts was like a half to 3/4" off.

It may take a few days but I can get you pictures to show this.

[Name Brand]

I used the entire TRX250 driveline in my SX. Click on the link in my signature to see why and how I did it. The only fab work I had to do was make a new lower shock mount on the TRX swing arm. With the TRX differential having a slower gear set you will end up with more torque and less speed. I corrected this by running 25'' tires which has worked great for what I do with that machine.

[obijuan]

I have seen every thread you have written. Lol. I guess I need side by side comparison of each part to see what is necessary. I might judt hack up and extend a stock swinger.

[Name Brand]

The '85 isn't the desirable setup. Upgrades on the '86 were the better sealed brake, and the way that the rear axle assemble can be unbolted from the swing arm. The '85 has to be disassembled piece by piece since the swing arm and 'axle housing' are the same piece. One could swap that rear axle assembly between swing arms if using all the '86-87 style parts.

What are you trying to accomplish?
I went for the lower gear and longer swing arm by using the entire '86 TRX250 drivetrain.
Longer swing arm with SX gearing would be the TRX swing arm and driveshaft attached to an '86-87 SX rear axle assembly
Stock swing arm and low gears would be the '86-87 SX swing arm with TRX250 rear axle assembly.

The TRX250 had a nine inch rear rim size in those years. I don't know if even the large bell eight inch SX rims will fit.

[TheRealFatShady]

Name Brand - Do you know if the TRX swingarm bolts up to the SX rear end? I had an 86 SX, I had two TRX swingarms, I believe different years as one had welded plates that looked factory on the top and bottom of the swingarm and the other one didn't.

The reason I ask is because I had to cut and bend and re-weld one to fit the SX rear end, and the other TRX one is the same (Either use the full TRX rear or cut and modify it.)

EDIT - Only thought is I ran into two 85's, and that is slightly different?

I attached pics. I cut this one up as it was all rusted. I may still use it after heavy re-enforcement, it was basically just spot welded after cutting and bolting it on to make sure it lined up. This should now bolt right on to my SX parts with just the modded swingarm and driveshaft.

Yes, that is candle wax, lol.

[obijuan]

My 85 parts look way different.

[TheRealFatShady]

I had overlooked it "The '85 has to be disassembled piece by piece since the swing arm and 'axle housing' are the same piece." - Name Brand.

That would make sense as to why your 85 setup is different. I guess it shows you can use just a TRX swingarm and driveshaft with your stock SX rear end, but you'll have to bend/cut and weld it to fit, and you'll keep the same gearing as before.

My pic is the 86? TRX 250 swinger that's rusted on top of the stock 86 SX swinger.

[Name Brand]

Until last summer I never had an '86-87 SX swinger to check if the TRX250 axle assembly would bolt on. I didnt have need to try. I can't recall what the mount on the axle side looked like and I have to wonder if it would be easier and strong to move that to align with the swing arm mount. I wish I knew for sure now. I wonder if your swing arm is bent; I have bent one myself after a wreck.

My swing arm is from an '86 TRX250 and looks just like the on in the pictures.

Sorry I can't provide more; I'm twelve time zones from all my parts and machines till next year.