I would not give up on the shaft drive just yet. What do you define as hot? It's likely that the insulation in your motor is rated up to 180 deg Celsius. Try measuring the brushes with a temperature probe after you heat things up. How many amps were you pushing through the motor? More amps will give you better acceleration (and make things heat up even quicker). And finally, what speeds will you be doing most of your riding at, what kind of RPMs will your motor usually be turning, and how often will you be riding up hill? Lugging the motor at low speed around home will heat things up because there is no air flow being generated by the internal fan in the motor. Pulling the same amps to maintain a higher speed, the motor will run cooler because of the higher RPMs. I have been running my motorcycle for years with a chain and a 14 tooth (now 13) front sprocket and a 41 tooth rear. That overall ratio sounds to me like it is close to what your shaft drive setup provides... unless I am reading your ratio backwards. Having said all that, I can ride my motorcycle around all day long at low speed without any heating issues at all. The times that my motor has been the hottest has been in the snow when I have used it to drag the kids around the cul-de-sac on a sled at very lows speeds. That's easily remedied by a well placed armful of snow, but the extra drag of towing the kids really heats things up. How well does your motorcycle roll? damon
> Date: Sun, 2 Nov 2008 08:26:43 -0500> From: [EMAIL PROTECTED]> To: > listserv@electricmotorcycles.net> Subject: [ElectricMotorcycles] BMW update> > > Another milestone (of sorts) in my BMW motorcycle conversion journey. I > > had played around with an Elec-Trak motor direct to the shaft drive, > which > proved woefully inadequate. From taking with several people it > seemed that > I really needed to go to a higher gear ratio (the 'built-in' > ratio is > 3.3:1); or, possibly, a bigger motor. Jim Husted found a nice > 7", 8-brush, > motor for me. I thought I'd try it direct just to see, > which I did > yesterday. It did pull away (slowly) from a stop and > actually had ok > acceleration, but the brushes got hot from my low speed > driving around the > yard.> > So I guess I'm finally convinced I need to add a gear reduction. I > had > hoped to use a planetary gearset, but really couldn't find anything > > appropriate, so it looks like chain and sprockets. Now I have my winter > > project.> > Too bad, as the direct drive was absolutely quite; really sweet.> > > - SteveS> _________________________________________________________________ When your life is on the go—take your life with you. http://clk.atdmt.com/MRT/go/115298558/direct/01/
