Re: [Re: Curtis POT questions ]

[Paul Anschel <PaulAnschel@netscape.net>]

I have experimented with different arrangement here.  I currently am using one
of the Curtis PB-6 pots attached to a standard throttle cable on a motorcycle.
 I have found that the potbox has enough resistance to rotate the throttle
back if you release although it has less return force than a standard bike.  I
have also experimented with attaching an additional return spring to the PB-6
arm that pulls the throttle back - this works pretty well.  I have been told
that KTA Services in California used to sell a throttle pot that would fit
right into the motorcycle throttle but I don't know if they still do.

-Paul


"David Roden" <roden@wksu.org> wrote:
> The Curtis 1205 that I've ordered for my motorcycle requires a 5Kohm pot.
> Can anyone tell me: 
> 
> 1) The wattage required of the pot. 

It's low current.  Half-watt should be fine.  You want high reliability, 
though, so avoid the cheap unsealed carbon pots.

> 2) Is it linear or log taper. 

I believe Curtis uses, or used to use, a custom taper.  Linear would 
probably be OK.  Log is probably not a good idea, because I think it 
would exacerbate the infamous Curtis lurch.

> 3) low ohms is slow, and 5 Kohms is full on, Right? 

I think I remember reading this.  It seems counter-intuitive (open potbox 
causes full on!), but the controller logic is supposed to shut down if the 
resistance is too much over 5K.  (My old Curtis PMC-25 uses 3 wires, so 
I'm not sure about the above.)

> 4) Does there exist a POT box that would handle a 2 cable (pushme-pullu) 
> motorcycle throttle system.

The standard Curtis potbox has a lever that turns maybe 70 degrees if I 
remember correctly.  It has a spring return.  This lever is linked to the 
pot inside the box.  I don't see why you couldn't add another cable 
bracket to the box and use the second cable, though with the spring return 
you might not need both of them.

Years ago I tried to rig my own potbox design, and had lots of problems 
with the linkage and with pot noise.  You cycle the pedal thousands of 
times a year, so you want something reliable.  I think the Curtis potboxes 
are worth what they cost.  

Good luck!

David Roden
Akron OH USA


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