My 69 sierra trail boss 500 polaris powered

[chazz79]

This is the new land boat.



Someone poured a ton of love into this aatv. It has been completely apart and had the tub rhino lined inside and out. Origional orange body was @1/8 inch thick but this thing is roughly 1/2" thick. The engine looks to be professionally sorted out and fabricated in, overall on par with something I would've done myself.



The added power hasn't affected the transmissions at all. The drive chains look worn as well as the sprockets. The chain is chinese so I'm guessing all these items were replaced when the engine was installed. I'm hoping someone here knows who built it so I can contact them and pick their brain (has to have been someone in the northern ohio area. Anyone that builds an AATV with a stereo, gun racks and "beverage" storage has to be a character worth meeting!

[Mike]

It definitely looks good. How fast is it?

[chazz79]

I blew two chains getting it off the trailer today so I really don't know. I already repaired the left side and I'll have the right side ready to go tommorrow when the real farm stores open tommorrow. The brochures said 35mph on a stock one so it should be pretty scary as it sits.

[chazz79]

I've repaired my chains and taken my first ride. This thing is very fast and unstable as anything I've ever strapped myself into. No brakes and very little reverse action makes turns impossible so I still need to do more work. Does anyone know where a transmission adjustment procedure can be found? If there's anyone selling factory service manuals I'd love to have one. It's a rocket for sure but I don't know how useful that's going to be in a woods situation

[jpswift1]

There's a 6x6World member who knows all about the Sierra Trail Boss. I think his username is Jeff Tboss. He'd probably be the guy to ask for the transmission adjustment question.

[Jeff t-boss]

NICE RIDE! As far as your tranny adjustments goes, there are threaded bolts sticking out of the trannies with jam-nuts against the tranny casing. There is an elaborate proceedure, but to simplify; loosen the jam-nuts and turn the screws "IN" evenly till you have light resistance and the control lever (On the tranny) does not move in either direction when you try to move it BY HAND. (Make sure that the control lever is pointing straight up/down depending on which type tranny you have. {There's an "Old" and "New" style, but the proceedure is the same for both.})Then back each one out 1/8 turn at a time until the control arm can be moved (By hand) 5 degrees in either direction. When you reach this, tighten the jam-nuts. (Vehicle IS NOT running during all this, and its best to disconnect the control rods from the control levers.) That should get you moving forward and backwards and steering left and right. You'll have to drive it and probably readjust once or twice. If that doesn't help, you have issues deeper inside the trannies, but I won't go into it unless you come to that hurdle. Also check your oil levels/condition. There is a 1/8 pipe plug in the front/back of the casings about 1/2 way up. As far as oil type goes factory specs were 1 1/2 pints of straight 30W (No detergents) motor oil. I've read about useing 90W or ATF, and have experimented with both. 90W absolutely no good for Wisconsin winters, and ATF (I'm testing that now.) shows no real gain or loss in performance or heat buildup as of yet. (These trannies DO get quite warm.) I have the ATF in one tranny and the 30W in the other, and see/feel no real difference in control. Hope this helps.

[chazz79]

I got it adjusted up pretty well but it's still not turning right. I have to yank the sticks pretty hard to get the directions to change. I back up and yank a stick to scoot a little one way and do a 90 degree turn in 5 tries. I was hoping for more smooth action and maybe some spins on center. In my neck of the woods no one has these and I've never driven one so I really don't know what to expect. It won't turn at all on dry pavement without some serious abuse, on gravel it fights with me, in dirt it's better. I have learned that it's not advisable to fly up the road at 40+mph and attempt a 180, bad stuff happens.

[Jeff t-boss]

First thing to remember is that with these type trannys, is that you have to keep the throttle up around 1/2-3/4 at all times. It's not like driving a car. Also if that doesn't help, then you most likely need to have your bands (2 in each tranny) relined.

[chazz79]

I have it all figured out. The trail boss is fine but the engine needs a cam. Operating a trail boss takes a degree of skill and the ability to modulate power from the engine. The spanked exhaust lobe on the polaris engine is holding it up from developing power enough to make it turn. Its a common polaris problem that's going to robb me of 500bones. Since this puts me past the point of no return equity wise I think I'll go ahead with my plans of building a stainless or aluminum hull. IF you know anyone looking for a rhino lined stock hull send them my way.

[jpswift1]

I didn't think 2 stroke engines had a cam. Do you mean that it's something like a rotary valve on a Rotax engine? I've worked on those before and that seemed to be a common problem with them.

[thebuggyman1]

I had the same problem with my radiator cap on a 68 beetle......Looked all over the place and could never find it.

If you are going to rework the hull, consider modifying it to accept larger tires. 25" tires on a trail boss would be COOL!

[chazz79]

Yup that's the plan. Stretch the wheelbase and get redesign the body to clear 25's on 12 inch wheels. The frame will also be narrowed to fit on tigher trails. It is a watercooled 4 stroke 2000 model polaris 500cc engine out of a polaris quad. It is a SOHC 4 valve design with three lobes. Two outboard lobes drive their own rocker for intake valves, and a single wider lobe drives one splayed rocker that taps two exhaust valves. It's a good engine that produces a solid 36hp in stock trim. It's a failure point in these engines that I have to work around for 500 bucks....

I have sheets of 10 guage stainless on hand but I'm afraid of the weight it'll add. I'd be a little uneasy floating the merrimac around. I can go aluminum but then I'd have to buy that Tig welder I've been eyeing and the wife would shoot me. My 1500.00 toy is already going to be up to 2g's and unsellable without taking a huge loss. In it's current undrivable state I may get 500 bucks out of it....again a huge loss. I might as well have fun with it because I can't afford to unload the thing.