Couldn't really find a thread where this belonged, so I thought I'd start a new one. There has been so much discussion across so many threads concerning MPG and 6-speed performance, I just thought this deserved it's own discussion.<br />
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It pertains mostly to the Harley conversions and the TG, but it may be of some interest to those that have the option to change transmissions regardless of brand.<br />
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In short, I had a junky 6-speed in a Harley Lehman conversion powered by a TC-88 Stage II. I had changed the tires and other things to get it geared just like I wanted and could cruise in 6th. doing 75-80mph at around 2750 RPM. Most of the time, I felt as if it was lugging the motor and usually stayed in 5th. The junky 6-speed finally gave-up-the-ghost, which afforded me the opportunity to put my stock 5-speed back in. I went from a stock 32-tooth output pulley to a 34 to reduce the cruising RPM's a bit. I now cruise at between 3200-3300 doing 75-80mph and 3000 at 70mph. This gearing is a little tall in first, but it will move on out.<br />
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I have checked the mileage I had been getting against the mileage I am now getting trying to duplicate similar rides. With the 6-speed, I generally averaged 30-31 on the interstates at 75-80mph and 33-34 on the two-lane back roads at 55-65mph.
The overall average was close to 32-33.<br />
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With this 5-speed and the 34-tooth pulley, I am averaging around 34-35 overall. To those that have complained about the lugging underpowered 6th. gear...I can tell you that running in 5th. at a higher RPM and less motor lugging has resulted in a slightly improved MPG for me. The trike sure feels a whole lot happier too.