85 sx differential fit an 87 250sx?

[JasonB]

just wondering: im trying to get atc-lindsey's 85 250sx ready for her and phill to go to Rogers memorial ride next weekend. Phill has an 87 sx they are trying to get the diff off of so they can swap it onto Lindsey's 85sx. They are exactly the same right? I think the brake drum set up is different between the 85 and 86/87, but the diffs are the same right? I havent played with removing it yet but will be on saturday; i think the brake drum on the 87 set up is frozen on there. is there a special way to knock that off? thanks guys!

[Dirtcrasher]

Diffs are the same, only the brake arrangement /tubes/axle/swinger changed.


I would fill the drain plug with something, stand it on end. The brake shoe linings fall off

[Flyingw]

Not so fast Dirtcrusher.... The diffs are not the same. In the pic you will see an ES diff. Note the machined OD where the axle tube sealing lip fits in to the diff. On the 85 the depth of that area is shallower than the 86/87. Fitting in to that is the axle tube that has a cooresponding male sealing lip that fits in to the diff. This sealing system changed in 86/87 with a taller sealing lip and deeper mortise in the diff housing casting.

What does this mean, and 86/87 diff will work on 85-87 250SXs but an 85 diff wont bolt up flush and seal right on an 86/87 swingarm and axle tube. If someone does want to bolt up an 85 diff to an 86/87 swingarm and axle tube, then the sealing lip shown on the pic needs to be ground or machined down. Its not a whole lot and I never measured the differance but thats easy enough to figure out. The truth is, Honda redesigned this to fix the water intrusion problem but they didn't fix crap. They still leak unless you lay a bead of silicone around that joint before you bolt it together. In fact, both left and right axle tubes should have silicone around the joints.

[JasonB]

thanks for the responses guys, and I posted that backwards! I mean to ask; will the 87 diff bolt onto and 85 250sx? and from what I comprehend from your post flyingW is that the 87 250sx differential will bolt up to the 85 bike. I am planning to tear into it in the morning at Lindsey's house to see what I can see. I think the brake drum is froze up on it though, so it should be fun to pry off. Im taking all my tools over with me and want to make it a quick job.