market, and since Word War II occurred during most of its reign, production wasnt all that high. The Knucklehead did form the basis of all big twins produced since, and today its one of the most valuable of all the classics. The Panhead was the result of a revised Knucklehead; while many felt that the life of the Knucklehead was cut short, the Panhead that replaced it for 1948 offered valuable improvements. Most changes involved the cylinder heads, which were capped with a redesigned rocker cover resembling an upside-down roasting pan, hence the name Panhead. The most noticeable of these were the switch to hydraulic lifters which automatically took up any slack in the valvetrain and didnt need constant adjustment. They also ran cooler, because the heads were made of aluminum, they were quieter and needed less maintenance. But from my own experience to just tighten the primary and rear drive chains are a chore. The transmission lock bolts need to be loosened then the whole transmission is slid back till the tension on the primary is correct, then lock down the adjuster arm, then lock down the transmission after making sure both sides of tranny are equal distances from the motor. Now you can put the bike on a crate and loosen the rear wheel so the adjusting bolts can be tightened, this too must be measured to insure the rear wheel is not cocked to on side. Then the axle nut can be tightened. In another three to four hundred miles the steps will need to be repeated. Not a good system on the EL model, on the FL model a primary chain tensioner was used which made life much easier. The Panhead was available in a 61 cubic inch until 1952 called an EL, and a 74 cubic inch known as an FL, which in 1965 was equipped with electric start. The Panhead had just reached its pinnacle in 1965 when Harley replaced it with a revised engine boasting (you guessed it) new heads. The Shovelhead digs in now, called so becaus...
