Yeah, I know having the motor down low is bad for spray, gravel, etc.
And, in general, batteries low would help to lower the COG. However,
the lower frame tube geometry make it very difficult to mount my present
batteries low. I'm thinking of adding a blower to the motor, in which
case I will control the openings to the motor and can keep stuff out. It
just turns out the motor will fit in very nicely in that space. It will
actually be a lower COG using the chain drive than the direct drive was.
Since I have a big motor (80lbs) and hope to go to Lithium, in the end
it should be a good design. I also have a short range need so I don't
need a lot of battery weight.
But keep me thinking! I haven't cut any metal yet.
- SteveS
Jeffrey Blamey wrote:
Is there any way to nest the motor higher to get battery weight lower.
With my PMG132 I high mounted the motor well out of the way of road
spray. It sits under the front of the seat back of the tank. Just a
thought since you are so early in stage 2.
Jeff Blamey
On Tue, Nov 4, 2008 at 6:57 AM, SteveS <[EMAIL PROTECTED]> wrote:
I know they made a lower ratio for the R75, but I didn't consider other
models. Might be worth a look, but probably can't get me more than 10%
higher.
I've been playing around with a gear or belt drive layout. Actually it may
end up working out better as far as fitting everything in the frame. The
motor can nest down between the lower frame tubes leaving a nice large area
above that could be made to fit a variety of batteries. I have some SLAs to
learn on, but I hope to go to lithium at some point, so this may end up as a
good solution.
I was disappointed for a day, but now I'm re-energized. I think I'll use a
chain drive first since it's cheap and I can try out a few different ratios.
If it's to noisy I can then change over to a belt drive once I settle on a
gear ratio.
- SteveS
john fisher wrote:
its a long shot, but different rear-end ratios were built for racing the
R75/5 and I think for the R100/7 bikes. Reg
Pridmore and others raced them with shaft drive. Reg hasn't had a shop in
years, but the folks at Mountain View or San
Jose BMW might have a ring and pinion lying on a shelf. Its also possible
that the gears from an R65 or R50 or R75 will
fit- in those days the bikes shared parts across the range. The R90s might
have had a different final drive ratio too.
Just a thought. ( rode an R90S and an R100RS for many years)
SteveS wrote:
So I guess I'm finally convinced I need to add a gear reduction.
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