|
 6in4, 6in5, 5in4, 6w/OD, 5w/OD, Right Side 6, Right Side 5.Oh, did I mention the optional kicker? If you understand the first sentence of this article, then you know a little about motorcycle transmissions. The aftermarket manufacturers of trannys, Baker, Rev Tech, Jims, just to name a few are...
offering options for transmission fitment to retro older bikes with today’s better gear and case construction and options on 5&6 speed gear sets. Back cut gears, Helical gears, these options offer smoother engagement and quiet operation with less backlash. Today’s trend of wide tire bikes has also had its impact with the right side drive transmission and primary kit. This keeps the rear tire centered and does away with the left side pull that tends to happen on wide tire bikes when the primary is offset to the left. This is great but also requires the purchase of a frame to accept the right side drive. These frames can accept 240/250mm tires and still use a 1.5-inch wide rear belt, or a 280/300mm with a chain. How wide do you want to go? The other big seller is the six speeds; the obvious benefit is the reduction of engine rpm at highway cruising speeds. The difference with the extra gear is the change in the gear ratios throughout the rpm range. Some six speeds have a close first gear ratio (2.94:1); this can add about 5-7 mph of usable first gear. I know with a stock trans I’m usually up shifting to second in a matter of feet. The sixth gear is usually (.86:1), which is considered overdrive with a fifth gear at a (1:1); the difference is night and day. Well, don’t think that it’s only the aftermarket guys cashing in on the six speed tranny, Harley has been offering the Screamin’ Eagle 6-speed transmission for some time now, and I’ve lost count of how many of these I have done. They offer it as a complete transmission or the trap door with all the gears complete with mainshaft, countershaft, and seals. This requires many special tools and additional gaskets for the primary. Any time a job like this is done a service manual will help you with torque specs and torque sequences. The stock case needs some modification to install the new gear set; a template is included to ease this mod. This article wouldn’t be complete if we didn’t look at Harley Davidson’s first ever factory 6-speed, Harley has dubbed it the 6-Speed Cruise DriveGearbox. It is only available on 2006 Dyna models and cannot be retrofitted to earlier Dyna models or any other models for that matter. The new 6-speed Cruise Drivereplaces the 5-speed transmission previously used on Dyna models. On the Cruise Drive6th gear is actually direct drive (1:1ratio which is a combination of the new transmission gear ratio and the new primary ratio). That means every time the engine completes one revolution, so does the rear wheel. This helps reduce engine rpm at cruising speeds, which also helps to reduce engine noise. The primary drives as well as the compensating components are new. Changes include a new primary drive ratio-1.35:1, compared to 1.44:1 on previous models. The motor company had a recall on 2006 Dyna models built between June9 and October 19, 2005. The gearboxes in the affected motorcycles had a defect which under certain circumstances could allow them to go into a false neutral position even though the neutral light is illuminated. Approximately 13,400 motorcycles were included in the recall. So if you have an old scoot that needs some new gears or a ground up build with a steamroller wheel on it, the variety of company and aftermarket transmissions are there to cater to the masses. I can’t wait to see what happens next. That didn’t take long, seems my newest biker rag just came in the mail, how about a “Redundant Neutral Detent For Positive Neutral Finding”, we could look into this a little more but that would be …………well you know. |
ROAD MAP 
