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INTRODUCTION
RESTORATION OF VINTAGE SNOWMOBILES HAS BECOME A PASSION WITH MANY INDIVIDUALS, PARTICULARLY OVER THE PAST FIVE YEARS; PARTLY DUE TO THE CURRENT "RETRO" TREND INITIATED IN THE MARKETPLACE. ONE EXAMPLE IS THE NEW FORD MUSTANG, AND THE UPCOMING DODGE CHALLENGER AND CHEVY CAMARO. RETRO IS "IN" BIGTIME. THE OTHER CONTRIBUTING FACTOR IS THAT A LOT OF US "BABY BOOMERS" WANT TO RESTORE OLD IRON WE DROVE IN OUR YOUTH, OR EVEN OWN WHAT IN 1970 WAS OUR DREAM SLED, BUT OUT OF OUR REACH FINANCIALLY BACK THEN.
THERE ARE A LOT OF RESTORATION CANDIDATES OUT THERE FOR SALE, PART OF THE EXCITEMENT OF THIS HOBBY IS SEARCHING THEM DOWN, AND HAVING SOME OLD LADY OR GENTLEMAN SAYING HE HAS A COUPLE YELLOW SLEDS UNDER A TARP IN THE BACK OF HIS BARN.
I HAVE HELD A PASSION FOR SKI DOO SNOWMOBILES ALL MY LIFE. I LIVE, EAT BREATH VINTAGE SKI DOO 365 DAYS A YEAR; MY GREATEST INTEREST IS THE THOUSANDS AND THOUSANDS OF PARTS USED IN THE ASSEMBLY OF THESE MACHINES. I SPEND COUNTLESS HOURS LEAFING THROUGH PARTS MANUALS, MEMORIZING PART NUMBERS, AND ILLUSTRATIONS. AS A FORMER SKI DOO DEALER MYSELF, I HAVE HANDS ON EXPERIENCE WORKING AND INSTALLING THESE PARTS, AND KNOWING THEIR FUNCTION, AND INTERACTION WITH OTHER ASSEMBLIES.
WITH THIS GUIDE, I HOPE TO OFFER SOME INSIGHT AND ADVICE TO NEWCOMERS TO THIS GREAT HOBBY. I WILL TOUCH ON EACH ASSEMBLY OF THE SKI DOO SNOWMOBILE, WHAT TO LOOK FOR, AND WHAT TO AVOID.
ENGINE
THE ENGINE IS THE HEART OF THE SKI DOO SNOWMOBILE. THE VAST MAJORITY OF SKI DOO'S BUILT AFTER 1963 USE A ROTAX MOTOR. THESE ENGINES ARE HIGHLY REGARDED AS THE BEST TWO STROKE ENGINE, PERIOD. THEIR LIGHT WEIGHT AND POWER OUTPUT ARE ALMOST LEGENDARY. THE WORKMANSHIP IS IMPECCABLE; ANYONE THAT HAS STRIPPED DOWN A ROTAX CAN ATTEST TO .
WHEN IT COMES TO REPLACEMENT PARTS, PERSONALLY I WILL NOT COMPROMISE. IT'S OEM ROTAX, RIGHT DOWN TO THE GASKETS. ROTAX OEM PISTONS ARE FORGED, AFTERMARKET ARE CAST. THE FORGED PISTON IS MUCH STRONGER, AND LESS BRITTLE THAN THE CAST PISTON. SO YOU ARE NOT PAYING FOR JUST A NAME, THE FORGING PROCESS IS MUCH MORE EXPENSIVE, AND INVOLVES STRONGER ALLOYS.
NOT TO CONDEMN AFTER MARKET PISTONS, IF NOTHING ELSE IS AVAILABLE, THEN THEY WILL 'DOO. IF YOU ARE REPLACING A BAD PISTON THOUGH, MAKE SURE YOU DETERMINE THE CAUSE FIRST, DOO NOT SIMPLY REPLACE THE PISTON, OR YOU WILL BE LOOKING AT ANOTHER PISTON FAILURE WHETHER YOU USE OEM OF NOT! THE MOST COMMON CAUSE OF PISTON FAILURE IS AIR LEAKAGE, USUALLY A RESULT OF LEAKING CRANK SEALS.
THE CRANKSHAFT IS A MAJOR COMPONENT OF THE ROTAX ENGINE. BUYING USED CRANKS IS A RISKY VENTURE AT BEST. UNLESS YOU CAN INSPECT THE CRANK PERSONALLY, OR THE PRICE IS NEXT TO NOTHING, I DOO NOT RECOMMEND BUYING USED CRANKSHAFTS. IF THE UPPER OR LOWER RODS HAVE ANY CORROSION OR PITTING ON THE BEARING RACES, MAJOR ENGINE FAILURE WILL RESULT. INNER BEARINGS THAT ARE BAD MEANS THE CRANK HAS TO BE "SPLIT" AND YOU ARE LOOKING AT BIG $$$. EVEN NEW OLD STOCK CRANKS NEED TO HAVE BEEN STORED PROPERLY.
IT'S EASY TO TELL AN OEM GASKET VS AFTER MARKET. MATERIAL QUALITY IS USUALLY SUPERIOR, ALTHOUGH SOME AFTER MARKET GASKETS (WINDEROSA IS ONE) MAKE VERY NICE STUFF. THE ONLY THING TO WATCH FOR, ESPECIALLY WITH FULL GASKET SETS IS THAT THERE MAY BE VARIANCES FROM YEAR TO YEAR IN THE MAKE UP OF THE GASKET SETS. THE DIFFERENCE IS USUALLY IN THE CRANK SEALS.
ELECTRICAL COMPONENTS, SUCH AS VINTAGE CDI BOXES ARE RISKY AT BEST, UNLESS IT IS NEW OLD STOCK. IF YOU NEED A CDI FOR YOUR T'NT RV, AND CAN AFFORD IT, CONSIDER A HEWTECH UNIT.
RECOIL STARTER PARTS? OEM IS BETTER QUALITY, FITMENT, AND DOO LAST LONGER.
EXHAUST SYSTEMS- VIRTUALLY IMPOSSIBLE TO FIND NEW, 'CAUSE THEY WERE MADE OF THIN STEEL, SUBJECT TO TEMPERATURE EXTREMES, AND ENVIRONMENTAL CHANGES, SO RUSTING IS A BIG PROBLEM. ANOTHER AREA OF USING YOUR JUDGEMENT IN BUYING THESE. THERE ARE A COUPLE PLACES GETTING INTO REPRODUCTION EXHAUSTS (SPAULDING VINTAGE), AND THEY SEEM LIKE VERY GOOD QUALITY COPIES.
SUSPENSION
BOGIE SUSPENSIONS ARE VERY SIMPLE, AND USUALLY TROUBLE FREE IF MAINTAINED. USUALLY NEW OLD STOCK BOGIE TIRES CAN BE FOUND, BUT EVEN BOGIES THAT HAVE BEEN ON A SHELF FOR 35 YEARS CAN SPLIT, SO KEEP THIS IN MIND. CROSS SHAFTS; MAKE SURE YOU KNOW THE LENGTH YOU NEED; THERE IS OBVIOUSLY ONE LENGTH FOR 18" TRACKS, AND ONE FOR 15".
SLIDE SUSPENSION; THERE ARE AT LEAST SIX OR MORE DESIGNS USED BY SKI DOO FROM 1970-79. HERE, IT'S A PERSONAL CHOICE, AS SOME OF THE AFTER MARKET PARTS ARE OKAY, NOTABLY THE SLIDER SHOES. IF YOU ARE RESTORING TO 100% ACCURATE HOWEVER, I DOO NOT THINK THE SLIDER SHOES CAN BE HAD IN THE ORIGINAL WHITE USED BY SKI DOO. KEEP IN MIND THAT NEW OLD STOCK SLIDERS CAN BE BRITTLE, AND SPLIT DURING INSTALLATION.
IDLER WHEELS? BE CAREFUL AS THERE ARE MANY DIFFERENT DIAMETERS. KEEP IN MIND THAT THE BEARING SIZE IS THE SAME FOR ALL YEARS.
WHEN IT COME TO SKIS, THAT'S A PERSONAL DISCRETION. SKIS ARE EXPENSIVE TO SHIP, AND THE AFTER MARKET ARE DECENT. THE LATE 60'S 1970 SKIS ARE NOT AVAILABLE AFTER MARKET, SO WHEN RESTORING ACCURATELY YOU WILL NEED USED OR NOS. AT LEAST THE SKIS CAN USUALLY BE SANDBLASTED AND PAINTED TO LOOK NEW AGAIN.
LEAF SPRINGS HAVE A TENDENCY TO SAG OVER THE YEARS, SO STICK WITH NEW OLD STOCK IF YOU CAN. I FEEL THIS IS AN OFTEN OVERLOOKED AREA WHEN A RESTORATION IS UNDERTAKEN. SKI SHOCKS; WITH USED OFTEN TIMES THE SEALS ARE SHOT RESULTING IN LEAKAGE, AND THE SHOCK IS USELESS FUNCTION WISE.
TRACKS? WOW, I COULD WRITE A GUIDE ON TRACKS ALONE. IF IT'S AN OEM TRACK, GET THE PART NUMBER, AND MAKE SURE IT'S THE PROPER NUMBER FOR YOUR MACHINE. AFTER MARKET TRACKS ARE OKAY, AGAIN, JUST MAKE SURE IT'S THE RIGHT ONE FOR YOUR APPLICATION. TRACKS ARE VERY SUSCEPTIBLE TO DRY ROT, SO USE YOUR DISCRETION HERE. ALSO, EXPENSIVE TO SHIP.
SPROCKETS; TRY TO STICK WITH NEW OLD STOCK, OR NEW AFTERMARKET. USED DRIVE SPROCKETS CAN BE BRITTLE OR WORN, OR EVEN SWELL UP TO THE POINT THEY WILL NOT ENGAGE PROPERLY.
DRIVE COMPONENTS.
DRIVE AND DRIVEN CLUTCHES ARE ANOTHER ITEM SUBJECT TO WEAR AND TEAR. TRY TO STICK WITH NEW OLD STOCK, AND MAKE SURE ON APPLICATION. THE PRE 1974 SKI DOO CLUTCHES WERE LESS THAN DESIRABLE, BUT DOO THE JOB AS WELL AS THE DESIGN PERMITS. THE PRE 74 MOVING FACE AND GOVERNOR CUP WERE SUBJECT TO A LOT OF WEAR, AND AS SUCH ARE RELATIVELY HARD TO FIND. BE VERY CAREFUL WORKING ON DRIVE CLUTCHES; REFER TO A SHOP MANUAL. THESE THINGS CAN SPIN AT UP TO 7500 RPM ON A TRAIL MACHINE, AND IF THEY FLY APART, YOU CAN BE LOOKING AT SEVERE DAMAGE AND PERSONAL INJURY. DRIVEN OR SECONDARY PULLEYS DOO NOT WEAR LIKE THE PRIMARY'S, USUALLY THEY ONLY REQUIRE BELT SURFACE CLEANING WITH STEEL WOOL, AND CAM SHOE REPLACEMENT. DOESN'T HURT TO REPLACE THE DRIVE AND DRIVEN SPRINGS AS WELL, AS THEY CAN LOSE THEIR TENSION THROUGH EXTENSIVE USAGE, AND RESULT IN LOWER PERFORMANCE.
CHAIN AND SPROCKETS ARE USUALLY FINE, THEY RUN IN AN OIL BATH, SO REPLACEMENT PARTS ARE USUALLY NOT REQUIRED. YOU MAY NEED TO REPLACE THE UPPER SEAL, JUST REMEMBER TO FIND THE PROPER PART NUMBER FOR YOUR APPLICATION.
COSMETIC AND CHASSIS PARTS
PLASTIC AND RUBBER PARTS TEND TO SUFFER WITH EXPOSURE TO ULTRAVIOLET LIGHT. USED RUBBER PARTS WHICH MAY LOOK GOOD IN A PHOTO, TEND TO HAVE MANY CRACKS AND "SPIDERWEBS" ON FLEXING THEM. PLASTIC GETS BRITTLE AND DISCOLORS. SO UNLESS THE PART IS EXTREMELY RARE, STICK WITH OEM NEW OLD STOCK. IN THIS AREA, ESPECIALLY WHEN IT COMES TO WINDSHIELDS, OEM IS BEST. I HAVE SEEN VERY FEW AFTERMARKET WINDSHIELDS THAT FIT VINTAGE SLEDS PROPERLY. MOST PRE 74 SKI DOO CABS ARE FIBERGLAS, AND CAN BE EASILY REPAIRED AND PAINTED. BE WARY OF DAMAGED POLYCARBONATE CABS; USUALLY NOT AN EASY FIX, AND DON'T TAKE PAINT TOO WELL.
SUMMARY
THIS IS A VERY BASIC GUIDE TO OFFER ADVICE TO THOSE THAT ARE NEW TO THE HOBBY. I DOO NOT CONSIDER MYSELF AN "EXPERT" OR AN AUTHORITY ON VINTAGE SKI DOO PARTS. THIS GUIDE IS BASED ON MY EXPERIENCES, BOTH AS AN AMATEUR RESTORER, A FORMER SKI DOO DEALER, AND A SELLER OF VINTAGE SKI DOO PARTS ON EBAY.
AS A RULE OF THUMB, REMEMBER THAT IN ALMOST ALL INSTANCES, OEM PARTS WILL BE SUPERIOR TO AFTER MARKET. YOU ARE NOT JUST PAYING FOR A BRAND NAME. OEM PARTS HAVE A LOT MORE ENGINEERING AND DESIGN INPUT, CLOSER TOLERANCES AND SUPERIOR MATERIALS TO AFTER MARKET. DOO YOUR RESEARCH; GET THE OEM PART NUMBER WHEN POSSIBLE. MOST OF ALL ENJOY LOCATING THE PARTS YOU NEED; THAT'S HALF OF THE RESTORATION CHALLENGE!
Guide created: 11/19/06 (updated 06/23/08)
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