I am new to the 120 seen as well. This info is posted on www.recmotor.com
. So far they are the best 120 aftermarket website i have found. they have several kits and parts to speed up the 120's.
Speed Tips For The 120's
1. The 120's have very small track drivers which cause an excessive amount of friction on the track drive lugs as the track moves, this causes poor acceleration and top speed. The fix for this problem is to run your track with the least amount of tension possible and lube the hyfax and drive lugs with cooking oil.
We have also found a drive cog alignment problem on the Arctic Cat Z120. The only real way to solve this problem is to remove the drivers and grind them to fit. We do not, however, recommend this because it might void the warranty. The Z120 has another high friction problem, that is the lack of track clips on every window of the track, long runs in limited snow or on ice causes excessive heat on the hyfax from the rubber. We recommend contacting your local dealer and having them install the missing clips.
2. Brake band adjustment is very important, not only for stopping, but also for maximum engine performance. A dragging brake can cause serious hp loss. The easiest way to determine brake band drag is to jack up the rear of your sled and run the engine at full throttle for 30 seconds. Then, shut off the engine and feel the clutch drum, it should be cool to the touch. If you feel any heat at all, re-adjust brake band to eliminate drag.
3. Radar testing has shown us that plastic skis will add over 1 1/2 MPH to the Ski-Doo Mini Z and the Arctic Cat Z120. The Polaris XCR120 comes standard with plastic skis.
4. Many hours of dyno testing has shown us that the use of Energy Release additive in the oil will keep the Suzuki, Honda and Fuji engines running cooler, which gives them max hp and torque even when the engine is heavily heat soaked from high RPM running.
Clutch Heat Tips
Clutch heat can cause performance problems on all centrifugal type drive clutches. There are 3 things that we have found in testing that can cause heat related problems:
1. Brake band drag which we refer to in the below tips.
2. Clutch drum bearing drag. We have found that bushing style clutch drums need to be removed on a regular basis and cleaned to prevent heat. Needle bearing drums like the one used on our RC-1335 clutches have much less coefficient drag which greatly reduces heat and need very little maintenance.
3. Clutch shoe slippage, which is caused by too high of spring tension and can be verified by a chattering sound and/or a jerky feel at engagement. This can be cured by going to a lower tension clutch spring. Dirty shoes can also cause slippage and can be fixed by removing shoes from the clutch and cleaning them with a good grade carb cleaner and drying them with air. Then take a small rat tail file and cut two small groves across the width of the shoe. This will give the normal dust and dirt a place to go giving you a more aggressive clutch.
Remember: 1. No brake drag. 2. Clean and lube drum bearing. 3. Clean and groove shoes = LESS CLUTCH HEAT.
Chain Tension Tips
Chain tension is very important for good speed, all sprockets and drive train have some run out. Rotate your track to find the tightest spot on your chain then adjust the chain to have approx. 1/4 inch of slack.
This will give you the BEST PERFORMANCE.
Rear Sprocket Break In Tips
By taking your rear drive sprocket and wire brushing the edges of the teeth on a wire wheel before installing you reduce chain side friction and have a smoother rolling chain this = MORE SPEED and BETTER TAKE OFF.
Grass Drag Tech Tips
GRASS DRAG WHEEL ALIGNMENT TIP: WE DO A LOT OF TESTING IN THE SUMMER ON OUR LITTLE SLEDS AND HAVE FOUND ONE AREA THAT MOST PEOPLE MISS WHEN SETTING UP FOR RACING AND THAT IS WHEELS ,WE FOUND THAT GETTING A PAIR OF 8 INCH AIR TYPE DOLLIES WHEELS AND MOUNTING THEM DIRECTLY TO THE SPINDLES WORKS THE BEST YOU CAN FIND THESE AT ANY TRACTOR SUPPLY STORE . MOST LITTLE SLEDS HAVE A LOT OF STEERING PLAY THERE FOR THE WHEELS TRY TO TOE OUT WHEN DRIVING CAUSING DARTING AND SCRUB SPEED LAY A 2X4 ON THE GROUND AND ROLL YOUR SLED WHEELS UP AGAINST THE 2X4 WHILE HOLDING THE SLED HAVE SOMEONE ADJUST THE ALIGNMENT PERFECTLY STRAIGHT. THIS WILL GAIN YOU QUICKER ACCELERATION AND MORE TOP SPEED.
Arctic Cat Z120 New Drivers
Have your local ARCTIC CAT dealer order the 2001 drivers for your 2000 sled it will reduce track drag and increase speed.
Polaris Xcr120 Plug Indexing
We have seen a improvement in performance on the Polaris XCR120 when indexing the spark plug , this means removing the plug,marking it where the plug gap is then reinstalling it so the plug gap faces toward the piston you might have to add 1 washer to the plug or try other plugs to achieve this.
Best Kept Speed Secret
There are many things you can do to your track to reduce friction but one of the main areas overlooked is the drivers the problem they have is there diameter it is very small which means their lugs stay in contact with the track lugs a lot longer, which causes the track to heat up and get sticky,causing drag and that causes lose of speed. Heres the tip COOKING OIL go to the local groceries store and by a gallon of cooking oil put it in a garden sprayer or hand spray bottle and spray large amounts of oil on the drivers ,bogie wheels,and track lugs. you will see a big improvement in performance and speed.
Clutch Problems 101
ONE OF THE MOST COMMONLY ASKED QUESTIONS I GET ON OUR TECH LINE IS, WHY WHEN MY SLED TAKES OFF DOES IT SOUND LIKE THE CLUTCH IS RINGING or THE TRACK IS JUMPING COGS. ESPECIALLY AFTER YOU HAVE JUST INSTALLED DIFFERENT GEARS FOR MORE SPEED.
(ANSWER) A CENTRIFUGAL CLUTCH ENGAGES AT A CERTAIN RPM, WHAT THAT RPM WILL BE IS DETERMINED BY WHICH SPRINGS OR SHOES YOU HAVE IN IT AT THE TIME. THE ABOVE PROBLEMS USUALLY OCCUR WHEN YOUR ENGINE DOES NOT HAVE ENOUGH POWER OR (torque) TO ENGAGE THE CLUTCH AND MAKE THE SLED MOVE. HERE ARE JUST A FEW THINGS TO TRY (1) GO TO A LIGHTER TENSION SPRING IN YOUR CLUTCH, (2) MAKE SURE YOU HAVE NO BINDING IN YOUR TRACK AND IT HAS BEEN LUBED ( as per our tech tip) (3) CHECK TO SEE THAT YOUR DRIVE CHAIN ISN’T OUT OF ALIGNMENT OR TO TIGHT (4) CHECK TO SEE THAT YOUR BRAKE BAND ISN’T DRAGGING ON THE CLUTCH DRUM (5) RUN NO HIGHER THEN 87 OCTANE FUEL. OH AND ONE MORE THING THESE LITTLE SLEDS WERE NOT DESIGNED TO HAUL AROUND ADULTS LET THE KIDS DO THE TESTING.
Power Charts For The 120 Engine
PLEASE NOTE THAT THESE RESULTS ARE FROM OUR DYNO TESTING, AND OTHER PEOPLE OR THE FACTORIES MAY GET DIFFERENT RESULTS. ANY QUESTIONS REGARDING THESE RESULTS CALL OUR TECH LINE 319-365-5391.
Stock XCR 120 Stock MINI Z 120 Stock Z120 SnoPro
Stock Z120 77.5 jet Stock Z120 90 jet
The Answer To The Most Commonly Asked Question
The most common question I get asked on our tech line is how much HP does my sled have? Here is the answer everyone has been waiting for, out of all the engines sent to us for modification we tried to be very fair and pick one of each brand that had close to the same amount of run time and type of use. We then installed our governor spring and pipe, which was set to the same back pressure as the stock pipe. We ran inertia dyno tests on all three of the engines and these are our results. You will also note that there are 3 dyno runs on the Z120 Cat, the only difference is the main jet size. This was done so Z120 owners could compare to the Z120 SnoPro.
Wheel Kit Speed Secrets
MOST PEOPLE DO NOT KNOW THAT THERE IS A RIGHT WAY AND WRONG WAY TO INSTALL A TRACK WHEEL KIT. WHEEL KITS COME WITH ONE OR TWO SETS OF WHEELS DEPENDING ON THE BRAND AND THE INSTRUCTIONS TELL YOU TO MOUNT THEM IN THE HOLES THAT OUR ALREADY IN THE SLIDE RAILS, THIS IS OK IF YOU ARE NOT LOOKING FOR TOP SPEED ON YOUR SLED, BUT IF YOU WANT TO FIND THAT LITTLE EXTRA SPEED ADVANTAGE PROPER WHEEL PLACEMENT IS VERY IMPORTANT. PLEASE REFER TO THE FOLLOWING DIAGRAMS BELOW FOR A BETTER UNDERSTANDING OF WHAT I AM TALKING ABOUT.