TAPP Clutch Tuning FAQs

What do the clicker bolt adjusters do?

The eccentric bolts called "clicker bolts" help raise or lower the vehicle's top RPM. Rotating the bolt to a higher number raises RPM because the ramp angle is increased. Rotating the bolt to a lower number lowers RPM.

What does the ramp position A vs. B represent?

Each Tapp Clutch ramp has two sides. "A" represents lower engagement than "B." Engagement can be raised by choosing position "B" while keeping opposing ramps balanced. Two opposing ramps must match - for example, two opposing ramps on "A" and two on "B" will raise engagement, while four ramps on "B" will raise engagement even more. Spring choice also affects engagement.

How can I change my clutch engagement?

Spring and ramps have the largest influence on clutch engagement. Springs come in different stiffnesses - for example, the blue spring is 100/190 and the black spring is 140/210, so the black spring will have higher engagement than the blue spring. The ramps also have an "A" and "B" side; using side "B" increases clutch engagement because it has a higher shoulder to overcome before the arm roller starts shifting out along the ramp. Arm weight does not affect engagement much.

If I switch from a button spider to a roller spider, do I have to recalibrate my clutch?

A roller spider is more efficient than a button spider because it has less rolling resistance, and the roller spider setup may run less arm weight. To determine this, install the same calibration used with the button spider, run it to read the top RPM, then adjust the weight to achieve the target RPM.

If I am increasing my horsepower, do I have to increase my shift arm weight, roller size, or change the spring?

Arm weight is adjusted to achieve target top-end RPM. Any change in the vehicle or driving conditions may affect top-end RPM, so adjust shift arm weight up or down to raise or lower RPM. Springs raise or lower engagement RPM and also influence shifting characteristics - a stiffer or softer spring can affect top-end RPM, but not nearly as much as a shift arm weight change. Increasing roller size can help add weight and reduce the amount of weight needed on the shift arm. For example, a set of 2 mm rollers weighs 61.2 g, while a set of 3 mm rollers weighs 73.2 g.

I bought a used Tapp Clutch. How do I know it will work on my machine?

Tapp Clutches are versatile, but there are specific fitment limits. The post must match your machine's PTO taper and offset. Calibrations can be changed if needed to suit your machine. Each Tapp Clutch post can be identified by its length and by the opening at the top of the post, which indicates whether it requires a specific washer, special bolt, or both.

How do you reduce belt slippage?

Belt slippage can be caused by calibration issues, a bad belt, oil or grease contamination, water, or incorrect belt deflection. Recent vehicle dimension changes may also require clutch calibration or gearing changes, such as changing to larger or smaller tires. Terrain and riding style can also require clutch tuning. Both clutches and the gearbox need to work together for the driving conditions - for example, a desert calibration will be very different from a mud or rock-crawling calibration.

My target RPM is different from what my gauge says. How can I get my machine to target RPM?

The first step in clutch tuning is achieving target RPM. If RPM is too high, add weight to the shift arms until RPM comes down to the target number. If RPM is too low, remove weight from the shift arms to increase RPM. If shift-arm weight does not make enough difference, springs can be changed - springs have varying compression ratios that can change top RPM, engagement RPM, and shifting characteristics. A stiffer spring raises RPM, while a softer spring lowers it. The secondary clutch can affect target RPM, but the primary should be adjusted for target RPM.

How do I tune my Tapp Primary Clutch?

Tune the Tapp Primary Clutch by adjusting the clicker bolts, ramps, springs, and shift-arm weight.

Clicker Bolts

• Lower numbers lower the ramp angle, which lowers the RPM. A lower angle allows an easier shift out into a higher gear.
• Higher numbers raise the ramp angle, raising the RPM. A steeper ramp angle resists the shift out, requiring more RPM, like a lower gear.

Ramps

• Ramp angle can be changed for different shift patterns, affecting driving characteristics. Ramps have two sides and are reversible.
• Side "B" offers higher engagement, often used for harder-hitting racing applications. They can be accessed through the cover windows.

Springs

• Springs resist the centrifugal force applied by the shift arms to press the sheaves together. This squeezing force moves the belt up and down on the clutch sheave faces. The first number describing this resistance is the pounds per square inch to start compression; the second is the resistance or pressure required at full shift out.
• For example: a Tapp Blue primary spring has a rate of 100/190 and the Tapp Black primary spring has a rate of 140/210 - the black spring has higher engagement and higher max RPM. See your spring chart for other options.

Weight

• The shift arms are weight adjustable using a combination of bolts, washers, and rollers, offering many adjustable combinations. Weight location also affects the shifting pattern - tip weight squeezes faster and harder, while lower shift arm weight back-shifts easier and quicker.
• Clutch tuning is a science and an art - the near-countless setup variations on a CVT work great when calibrated correctly.

What primary clutch bolt do I use for my Tapp Clutch, and what clutch puller do I use?

Use the correct bolt and puller for your application:

• Can-Am X3: TRA bolt and stock TRA puller
• Can-Am Defender: TRA bolt and stock TRA puller
• Polaris Pro R: stock bolt and Tapp spacer (provided with the Pro R clutch) plus Evolution clutch puller SKU 4002020003
• Polaris XP Turbo: part #5121 (included with purchase) or Polaris part #7520531
• Polaris 1000: Evolution clutch puller SKU 4002020002
• XX Wildcat: stock bolt and stock Yamaha puller
• Kawasaki H2: Evolution clutch puller SKU 4002030001
• Yamaha and Arctic Cat 998: Yamaha stock bolt and Yamaha stock puller
• Skidoo: TRA bolt and stock TRA puller

How can a primary spring help my performance?

Primary springs live inside the drive clutch, also known as the primary clutch. The primary spring controls engagement RPM and operating RPM from low to high speed. Longer, stiffer springs with more coils generally create higher RPM engagement, while smaller, less stiff springs with fewer coils generally create lower RPM engagement.