Simple spintron for testing cams and lifters

When cams are worn, they usually develop flats at the points where they give maximum acceleration to the cam followers. The closing ramp is also important - if it does not moderate the descent of the follower, the cam can be a valve-dropper. A mild cam can be better than a savage one - it also affects' the way the power is delivered, if the bike is slowed and the rider is forced to slip the clutch in the middle of a corner, more horsepower is sometimes not the best answer. The timings usually affect the position of the powerband within the usable rev range. A peaky power band can be moderated by the exhaust system, but a restrictive exhaust system can cut the top off the usable rev range. The timings also affect how strongly the exhaust system resonates. A 2 into1 exhaust system works better with an earlier exhaust valve opening point, but the noise is louder. The usual exhaust opening point is about 80 deg, BBDC. Mine is 94 deg, BBDC with a 2 into 1 pipe. Megaphone exhausts with a peaky power cam often give good power but a bad ride. For racing, a long stroke motor is usually safer than a short stroke motor. With megaphone exhausts, a race cam and a short stroke, the power can come on with a bang and send the bike sideways in the middle of a corner.