i'm looking for some performance ideas, trying to make my sled a nasty trail machine. all the guys i ride with are riding 700's just trying to stick to there heels dont need to beat 'em. any info would be great. this is my first skidoo???
welcome to the forums. I doo have a few notes on the machs, however I think thumbdoctor will beat me to it :wink: . mine are packed away, I know it for sure. I personally think that is one of the best sleds for the trail ,if its smooth. they handled so flat through the curves. just lacking on travel. my zx picked up the inside ski more than those.
1) Replace those PRS lead skis with good plastic light weight items.
2) Disassemble the front suspension and replace the worn out (expensive) lever pivot bolts(called "Flanged Screws") with high grade steel bolts(need to shorten and grind nut thinner)
3) Replace front shocks with gas units (they fade fast under trail conditions
4) Add 1/2" shims to front PRS shock springs (replacement HD springs are no longer available)
5) Make sure the front camber angle is 0 degrees (straight up at the king pin) to reduce scrub
6) Remove skid and replace / repair all worn out shafts ,pivots and linkages, lube everything with low temp grease including repacking all bearings with low temp.
7) Replace front skid shock with a newer HPG unit with 150 LB springs.
8) Replace rear skid shock with a newer HPG unit with stock installed (90 LB)
9) Align skid in tunnel using shims to assure the 16 inch track is well centered and suspension is square.
10) Double up the guide cleats on the track (those skids were hard on cleats in the twisties)
All the above will assure you the suspension advantage over any likely equipped sled at the cost of less total travel. Much of the parts can be had from sled bone yards and after market suppliers. The standard Progressive Reaction Suspension has a lower centre of gravity than newer sleds so it can rail on smooth trails but be aware!, it's a lot heavier being steel so it carries more weight into corners and stopping. Best way to manage that set up is to power through the trails and use the brakes to modulate corners without letting up on the throttle. The biggest improvements are to be had in the skis and camber angle as the carbides need to be 90 degrees to the snow surface.
1) Remove primary TRA clutch and clean and inspect it for worn out components.
2) Replace Primary spring (Yellow Yellow 100 - 230 LB) with new or for more engagement and operating RPM use BRP (Black 415 019 500 185 - 410 LB)
3) Throw away the secondary pulley and install a newer Formula 3 adjuster unit with a 50-degree cam in it (much better cams and bushings available)
4) Remove windage plates from the secondary
5) Preload secondary beige spring to 15 Lbs. (better back shift for twisties)
6) Clean chain case & inspect gears (26 : 44 ratio) replace upper gear with 25 tooth
7) Replace the chain case lube with Amsoil synthetic or Dextron IV trans oil
The job at hand here is to add efficiency to the transmission of power. Old worn out components rob effective torque multiplication and newer technology prevails. The old 2 adjuster secondary clutches don’t hold up well to heat and repeated cycling because the bushings are too small and the adjusters are 180 degrees apart leading to high RPM wobble and accelerated belt wear. The TRA springs are always sacked out and lead to poor launch and back-shift. Clutch kits are more available for newer Formula secondaries. Brakes:
8) Check mechanical brake system for drag and disable automatic slack take up system
7) Check brake pad thickness.. You'll need them !!
Go through the entire chassis looking for any source of drag, the brakes are a sore spot on the prs chassis, just feel them after 1/2 hour sledding without using them and you will find that their hot. The automatic slack adjuster is too aggressive and makes them drag, just bend the spring lever away from the star wheel and make sure the brakes are periodically adjusted.
I have another article on rotary engines here if your budget allows. There's no shame in a stock motor well set up.
If I had to guess, I would say you have the wrong sled unless you are gonna be on very smooth trails. Its not easy to go fast if you're bouncing up and down all the time because the mach 1 has very little suspension. I was looking into one because they seem fast (which is good for you) but then I decided against it because they have practically no suspension. I would just work on the engine I guess and do main things like get a pipe, maybe new shocks and probly new springs for the tunnel. The best thing you could probly do to improve overall power would be to bore it out. Just a few simple ideas.
Don't beat me up to bad guys. But I put an Extra12 fron a 1996 Polaris XLT 600 in my 92 Mach. The only parts I needed to make iut it fit were 2 1 inch spacers for the rear arms. Spacers from a chrysler 727 torqueflight tranny mount in an older dodge pickup are exactly what you need. check it out.
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