Wed May 20, 2009 1:46 pm by Randall
Howdy folks,
Back when I was running a custom bike shop in the 80's guys would commonly come in with new 1000cc Sporties or 74" Shovels and want an S&S Super and straight pipes installed. I'd ask them what they wanted to do with the bike and usually they say they just wanted to cruise around. I'd tell them that the combination of carb (the Super had no accelerator pump) and pipes they wanted would likely result in less power than the stock Bendix or Keihin in the low and mid-range of the power band where they were doing most of their riding, but they didn't want to hear it. The Super would work acceptably with an 80" engine but to see any real benefits you needed 84" or better. We used to install Mikuni cable-actuated accelerator pumps on the Supers to help cure the hesitation you'd get on smaller motors when the throttle was snapped open suddenly. That said, the Super was very well-made and reliable. The new shorties with built-in accelerator pump should be even better.
I ran a round-slide 38mm Mikuni for awhile on my '46 FL 74". It performed well, but with fatbob tanks it was neccessary to run a throttle cable with a 90 degree elbow where the cable entered the top of the carb. This would occasionally hang-up the throttle cable. I could usually snap the throttle open and shut to break it loose and get it to idle down, but once, in heavy San Antonio traffic, it hung in the full open position when I did this, resulting in a bent pushrod before I could shut the racing engine down. I replaced the Mikuni with a 38mm butterfly-throttle Keihin from the take-off pile and it worked well for years.
On the 80" Knuckle I'm riding now I have installed a CV Keihin. I had some initial teething problems with it, but after replacing the aftermarket "tuner's kit" that I'd initially used in the rebuild with factory parts, it is running great. CV Keihins can be had for little or nothing, mine came free from the take-off pile at a friend's shop, and with the proper jetting work great. That'd be my recommendation for a retofit on a stock 74".
--- Randall