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Clutch weights change game
As spring options became a staple in sled tuning, the next racer secret was made public. The clutch weight.
The most commonly used tuning part on the market (clutch weights) has not changed much in concept since it was first introduced. BUT, large improvements have happened ability to add weight in multiple positions, the amount of weight along the clutch arm itself, and improved shift arcs. Even though the basics of many clutch weight theories have been around since the mid 70’s (much of it from early 70’s Yamaha racing) it never quite caught on till the late 80’s. Most of it started by racers welding different clutch weights to achieve the proper gram-weight they wanted, in the proper place.
This early welding on weights was one of the only ways to change how much and where the tuner required the weight. There were issues that arose with the welding as it was not only unsafe but it changed the temper in the weights, and it was also inconsistent and hard to replicate. You often ended up tuning one machine very precisely but could not exactly replicate it to the next. So, the adjustable weight was invented and appeared quickly in the tuning market. The advantages of the adjustable-mass-distribution weight are the ability to accelerate and de-accelerate the clutch weight throughout certain shifting points of the clutch. These have become a standard in every racer and tuners’ clutching bin. The adjustable weights are now sold as part of many standard ‘trail’ clutch kits as well to improve performance, and give the customer adjustability of tuning for rider weight, altitude and conditions.
Through the late 70’s to mid 80’s there were great improvements in primary CVT tuning but it was during the late 1980’s that the move toward tuning the secondary clutch (along with the primary) began to happen. The top racers in the field had to keep moving forward as most of the racing field was acquiring the correct primary clutch parts and gaining primary tuning knowledge. So, knowledge of the helix and secondary spring separated the top minds in clutching in the late 80’s from the beginners.
Manufacturers up until the late 1980’s sold helixes in straight angles only, this was the only production option available. Just as racers were grinding on clutch weights, the straight angle helix was being modified. Soon the multi-angle helix became a staple. Many early prototypes were done entirely by hand by grinding all three ramps. A crude, but effective way to increase or decrease shift angle. These new tuning options coupled with a few new torsional spring options made huge improvements.
Reminiscing with seasoned tuners, many say they had a hard time believing some of those early helixes even worked! But it was their hard earned testing and racing that paved the way for the performance options we have today. The addition of CNC machines into the manufacturing of snowmobile performance products produced a perfectly replicated multi-angle helix. A big change from grinding the ramps and checking it out by line of sight.
The modern helix comes in an infinite amount of possible angles and compounds. The latest advancements are fully adjustable helixes. Amazingly this was built and tested in the late 80’s but never made it to market due to its reliability, material, and cost effectiveness.