From article <richard.711657035@tdsb-s>, by richard@mais.hydro.qc.ca (Richard Patenaude):
> At the club i race, we can only use stock speedwork motors (Dirt Oval), my problem is that all the A main racers know how to get more RPM's out of their motors without opening the can....does anyone out there know how to do it and would be nice enough to tell me?
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> Tired of being blown away!!!!!
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> Richard
If you are really serious about this, the first thing you need to
do is to get access to a dyno. That will give you the measuring
tool you need to understand the results of any changes you
make. The next thing you need to do is realize that you are
conducting a trial and error scientific experiment. Document what
you do carefully, and do everything possible to keep the test
parameters the same (e.g. voltage, load, etc.). Finally, you need
to try a bunch of changes out and see what gives you the most RPM
and torque. Here are some things to try:
Various brush/spring combinations. Your mileage may vary, but I
have had good luck with stock motors using the Reedy 1/12th scale
competition full brushes with Bud's purple (heavy) springs. You
will also want to see the effects of soldering the brushes
vs. using hook and eye.
Use jeweler's rouge to polish the bushings where they meet the
comm. You can also chuck a new stock motor without springs and
brushes and run it in a dremel tool for a while without
lubrication to break in the bushings.
Get a spring thing and experiment with spring tension.
Get a hood alignment tool and use it.
Use comm sticks on your motor after every run to keep the comm
clean.
Remember, dyno the motor after everything you try. Good Luck.