Just bought a used TRX300EX -1997 model. The poor bike was run hard and put away wet by the past 2 owners with no maintenance ever done. I've changed the oil & filter, front brake pads, cleaned things up, now I need to adjust the chain. I have about 2 1/2" of travel in it. But for the life of me, I cannot figure out how to take the slack out of the damned thing! Would go buy the factory service manual, but the wife is out of work for the summer to stay at home with the kids, so another $50 is a big NO-NO right now!
One other point, the big nut that supports the axle bearing, it looks like some yahoo tried to adjust it and broke 1/4 of it off and applied RTV sealant at the thread joint. What do these babys cost to replace?? I'm going to avoid this repair until the fall though.

 

It's very simple.
Look at the axle bearing carrier (the thing at the end of the swingarm where the axle goes through) in the back of the quad. There are two allen head bolts that are bolted in the rear of the carrier. Loosen those.....
Now look to the left of the axle carrier, there is a "slot" where you can stick a large screw driver or pry bar in and twist the axle carrier itself. This twisting of the carrier is actually what loosens or tightens the chain.
Twist it until you get the chain tension just right and then tighten the two bolts back down.
I'm not totally sure what exact specs for how tight it should be is, but i do want to warn you that you do need some slack in the chain. If it's too tight when you come off a jump you'll snap the chain.
Hope that helps
Mike

 

Thanks, Mike. The specs are 1 5/8 slack according to my sticker on the housing.

 

i Run mine with about 1 1/2 inch of slack. So far nothing has happened. I'm pretty sure thats what most people run around here. Oh and ScottsGT, you want to make sure you oil your chain about every other ride. I know I was in the mountains and this guy didn't oil his. We stopped and checked his chain to see how much slack was in it. When we pushed it up it stayed there. It had no oil on it to go back down. Luckily we got back to the camp site without it breaking. Be sure to oil it. Also be sure to oil your break and clutch cables. You definately don't want either one of those to snap.

 

every 3 rides, i take my chain off, put it into a pan with royal purple waterproff grease, and heat it over an OUTDOOR stove till the grease gets nice and hot and runny, and seeps into all the rollers and rings, and stir it around a little. then take it out, wipe it down with a rag, and go slow for a while till all the excess grease spins off and wipe it off the bike. the chain could go for the whole summer and not need oiled, but i ride in a lot of water and deep mud, it could go for a month, but i ride like 4 days a week, so it takes a beating. it really protects the chain!!