250sx; questions,repairs and upgrades...

[Name Brand]

I've seen a few questions as to what people have done with thier 250sx machines; here's mine.

I recently purchased this fuel tank. I've been looking for something that holds enough to completely refill my main tank and sits inherently stable. All the fuel tanks I've been seeing are far more vertical than horizontel and tend not to stay tied down during some hard riding. This tank is meant for a Ski-Doo snowmachine. It holds three gallons and has it's own pour spout and vent. It sits very nicely on the rear rack and stay's well put with only two bunjee cords. It comes to the rear of the seat and is very comfortable to recline against with it's curved front. I must say it looks very good on the machine and almost seems like it was made for it.

[MTS]

They also Make a Flat jerry can that will velcro it to your backrack and let you Stack/stap stuff on top......

[Name Brand]

Next off is the extended swingarm; it is the factory swingarm and rear axle from an '86 Fourtrax250. Here is the thread all about it; http://www.3wheelerworldforums.com/s...0sx+swap+gears
The lower gearing has slowed down the machine quite a bit, but I plan on getting 25 inch tires next summer which should bring me back up to the factory speeds. With the extended swinger I should be able to fit them. Note on my homemade bracket (where the bottom end of the shock mounts) there are three different holes for placing the shock. I am running the Fourtrax shock right now but will probably swap back to the SX shock. I've noticed no real loss of turning, but it does seem to climb steeper hills easier. Becuase this is from an '86, the rear braks is also the superior sealed drom type.

[Tri-ZNate]

so how much more length did you gain with the TRX swinger?

[Name Brand]

This is my snorkle. After a few too many hydro's and ugly crankcase and rear diff fluid I decide it was needed for the deep water crossings I have been doing. It is made out of 1.5 inch ABS pipe. The first part is simply a sweep 90 connected by a very short piece of pipe to an inline 45. The inline 45 was trimmed just slightly on the end plugs firmly right into the airbox. I simply removed the clamp the holds the factory rubber duct on and push it out of the way. The tall piece of pipe is removable from the curvy bottom piece. I store the curvy piece in my saddlebag and the tall piece below my rear rack with a bunjee cord. At each connection I use a short piece of bicycle intertube to hold the two connections even more firmly and to make sure no water gets in. I also have run my rear brake, rear diff and crankcase vent lines into my airbox. This has worked very well and I have not gotten water into these places since doing so. With the snorkle I can go through water over the top of my gas tank; much deeper than the factory setup. I've plugged the drain hole in the airbox. The snorkle doesn't interfere with riding either. I drilled holes across the top off the snorkle so that my shirt doesn't plug the end again.

[Name Brand]

This horn is from a 1991 Geo Metro. I bent the bracket it cam on 90 degrees and bolted it to the bottom of the upper triple tree using an existing bolt. This also put the drain hole on the bottom. The horn does not hit anything when the front is turned either direction. I put a momentary switch with waterproof cover in the factory switch unit on the left side handlebar and wired the horn to an always hot wire on the ignition. Even though it is a small car horn I assure you all, it is really loud.

[Dammit!]

Man that thing looks like a Humvee on three wheels.

[Name Brand]

The Fourtrax swingarm adds about three inches to the wheelbase. The factory SX brake cables work with it too. Here's a picture from a recent ride that shows the extra length fairly well.

I need to replace the ones missing from the back tires, but all three tires are studded with half inch hex-head sheet metal screws for winter. I'll buy new tires next summer. It stays put on the ice by itself. but with enough thottle I can still break it loose.

[Tri-ZNate]

man that is a sweet setup. very nice Job

[Name Brand]

This is what I had to fabricate to make the TRX swinger work on my machine. I connected the two front crossbars on the swingarm with a piece of 1.5 inch square tube with a 3/8 inch hole for the front bracket mounting bolt. I used the same type of square tube with 3/8 inch hole in the back on the axle centered below the TRX lower shock mount. This shock mount is unused but can be seen in the pictures above. I made the bracket using 1x1.5 square tube spaced 1.5 inches apart; just wider than the shock. There are three sets of holes that the shock's lower mount can be bolted too. The upper shock mount on the frame is unchanged.

The bracket is removable and is the first thing to come off when taking apart the rear. The front and rear mounting bolts and the lower shock mount bolt are removed and the bracket can then be pulled downward and off the swingarm. Disassembly is then continued normally. The '85 style swingarm and axle had to be taken apart piece by piece; this '86 style can be taken apart in sections - bracket, shock, rear axle, swingarm... done far easier and quicker.

For those wondering about the durablity of this setup I did crack and bent the swingarm once after a bad wreck; details are here- http://www.3wheelerworldforums.com/s...ad.php?t=61058
The swingarm cracked the top of the forward crossbar near the right side pivot. All of my welds were not damaged; I had to find and replace that swingarm but I am still using my original homemade shock bracket. So yes, this is the third swingarm my machine has had.

[Name Brand]

I thought I would update the thread on my machine and show of some pictures of the new tires!

The rear tires are Kenda Bearclaws; 25x12x9. The front tire is a Goodyear ATT912; 25x11x9. The rear rims are from an '86 Fourtrax 250. I could not find a 9x8 rim for the front so I took an extra rear rim and narrowed it to 7.5 inches wide. I would have gone 8 inches wide, but couldn't becuase of the backspacing. 1/4 of an inch less on each side won't matter.

The front tire does not rub. I've had it on a few rough rides now. My new rears do not rub either. Do keep in mind my swingarm is 3 inches longer than a stock SX. The right tire comes within an 1/8 inch of the side of the muffler but the rubber doesn't touch it. It does get scrapped by the mud the tire carries, but no big deal. The old tires had some extra sidewall lug which did rub the muffler. I like how the tires stick out past the rear rack!

Having real tread is a huge difference. I ran this machine for the first five years I had it with the original nearly bald tires still on it. I had to swap to the spider-claws in the pictures further back in this thread for a season when I replaced my rear axle. It is constantly surprising me at what this machine will pull itself through now. Also how much less the front end slides around on slick trails when trying to turn. The lowest point on the machine is the bottom of the skidplate on the rear differential. From that point to level ground there is now 8 inches of clearance!

The two pics on the right are from the Watermelon Trail behind Homer, Alaska.

[Nick_R_23]

Those tires look HUGE on there!!!! Great job on the build, really turned out nice!!! I bet itll really eat through the mud!!

-Nick

[dirt bike dan]

looks really good man!! bet itll float like a champ with those 25s!!

[mapyang]

Nice Sx all you need now is a trx300 engine then nothing will stop you. I put 22x12.5x8 spidertrac tires on my 1985 sx and the tires rubbed on the rear brakes so i bought 1.5 inch wheel spacers from www.highlifter.com. I got to say it handles nice not tippy at all its 46 inches wide tire to tire now. Go luck with your ride.
Drew

[oldskool83]

Looks like a freaking tractor.