Note: If you ordered this prior to 11/13/20 there is an interference issue. New bolts are being machined and sent out. Please reach out to me to ensure that you get the updated version.
Setting the chain tension on Sidewinder and Viper is not definitive and yields a sense of uncertainty. Some will argue that its been that way on previous Yamaha's, but the previous Yamaha chain case life was not so sensitive to chain tension. The pro cross chain case uses much longer chain, so there is more stretch to keep after. The top gear bushings are also a known wear item and I feel part of the problem is chains are being run too tight. When the adjuster bolt is threaded in too far it applies more tension than is intended by overriding the natural tension provided by the spring.
The BOP tensioner incorporates a depth rod into the adjuster bolt design. The depth rod has 1/16" increments on it, with the first line( from left) indicating the rod is flush with the end of the tensioner bolt. When setting tension one simply slides the rod in until it hits the tensioner and then turns the tensioner bolt in until the first line. This method of adjustment ensures that one can be certain they are not applying additional force.
The depth rod can also be used to measure how much the chain has stretched over mileage intervals to help one determine service intervals for adjustment and replacement of chain. If the chain has stretched since last set, the rod will slide in beyond the first line. You can then measure in 1/16" increments the gap between the tensioner and tensioner bolt.
The rod does not remain in the bolt at all times. The small bolt and washer threads into the tensioner bolt head to cap it off and prevent any oil from leaking out.
Retail price is $45