Model Forum / Radio Controlled / Land Models / December 2003

Hey Larry...helpful hint:

http://www.tinyurl.com

According to some info I found, the F201 uses ball diffs front and
rear. The diffs are adjustable, meaning that you can tighten a screw
or nut that mashses the entire diff together.

So, do this:

 (1) Remove both differentials.

 (2) Get a pair of scissors.

 (3) Place a differential between the scissors, so that the blades of
the scissors are seated into the slots of both outdrive cups. If you
do it right, it will look like the scissors are cutting into the
outdrives.

 (4) Grab the main gear (the big, wide, round gear) of the
differential and try to turn it with your fingers, while the outdrives
are locked in position on the scissor blades.

 (5) Can you turn the main gear easily? If so, follow the kit
instructions to tighten the differential. That probably means
inserting a hex key into one of the outdrives and tightening it, while
keeping the other outdrive locked up. But it's been years since I
adjusted a Tamiya diff, so check your manual.

 (6) Keep tightening until you can _barely_ turn the main gear with
the outdrives locked up. Then tighten it just a little bit more (maybe
1/4 turn or 1/2 turn) and you're done.

 (7) Grab an outdrive in each hand and turn them opposite
directions. They should turn smoothly in opposite directions with
little resistance. If there is a lot of resistance, then the diff is
too tight.

 (8) Repeat above with second differential. Traditionally, the front
differential is adjusted to be slightly looser than the rear, for
better front traction in the turns. But for initial testing, you
probably want them both very tight.

Try checking all the key spots with a voltmeter, or a little 6V light
bulb, until you find the power loss.

Reversing polarity on the servo probably won't hurt it -- I think they
have a diode to prevent that sort of thing.

Rick R.

Larry,
It just so happens that I am one of those folks that who put together
kits and the like for guys who cant or dont want to.
However I am in Milwaukee.
So try this, Go to your local hobby shop and ask if they offer this service.
If they dont, ask if they know anyone who will do is on the side.
Often times the counter sales guys will do it for you on their own time.

I used to build all the display kits for a Hobbytown USA near my house.
Any repairs or help his customers needed were sent my way.
I am always happy to help... for a few bucks of course.

Hope this helps, this kit you choose is of very high quality and performs
very well, but it is not meant for first timers.
It is admittedly a tough one to build. Dont feel bad for struggling with it.

John