Author Topic: which throttle cable  (Read 8613 times)

Offline dougrs

  • Motobrick Curious
  • Posts: 45
which throttle cable
« on: March 22, 2015, 10:04:14 AM »
Hey,
I need some assistance in sorting out which throttle cable I need. Some background first. The bike was idling high, but when I pushed on the idle adjuster screw, the throttle body would go down and the bike would idle  fine. I greased the gears up in the hand grip assembly and the stickiness of the throttle assembly improved a bit. However, when I turn the bars to either side and release the throttle, the throttle body assembly will not slap back down to the resting position. I believe I need a new cable.

So I am confused as to which cable. I have a standard '94 K75.

Do I need the longer or shorter cable?

32731457376 accelerator bowden cable Length 1025 MM (http://parts.bmwmotorcycles.com/p/BMW__/ACCELERATOR-BOWDEN-CABLE-L=1025MM/42761111/32731457376.html)

32731457378 accelerator bowden cable Length 1142MM (http://parts.bmwmotorcycles.com/p/BMW__/ACCELERATOR-BOWDEN-CABLE-L=1142MM/42761113/32731457378.html)

thanks for the help,

-Doug
  • MD
  • '89 Yamaha FJ1200, '94 BMW K75

Offline johnny

  • TrailBrakingThrottleWhacker
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Offline rbm

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Re: which throttle cable
« Reply #2 on: March 22, 2015, 02:36:01 PM »
However, when I turn the bars to either side and release the throttle, the throttle body assembly will not slap back down to the resting position. I believe I need a new cable.
First check whether or not the TPS switch on the end of the TB assembly is sticking. Number 6 in this diagram:



Loosen the two allen screws that secure the TPS switch to the rail so that the switch is free.  Test your throttle, also from lock to lock.  If the throttle no longer binds, the TSP was hanging up the butterfly valve shaft.  If the throttle still binds, it could be a sticky cable or it could be misrouting of the cable.  When adjusting the TPS switch, take special precaution not to press downwards on the switch as you tighten the screws; it is a natural reaction as you try to hold the switch in position but the downward pressure causes the binding.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline dougrs

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Re: which throttle cable
« Reply #3 on: March 22, 2015, 02:55:53 PM »
I removed the tps and still had the issue.
  • MD
  • '89 Yamaha FJ1200, '94 BMW K75

Offline dougrs

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Re: which throttle cable
« Reply #4 on: March 22, 2015, 03:16:12 PM »
I put the TPS back on, discovered that throttle cable was binding on clutch cable and I fixed this. Throttle response seems good now, No bindin when turning the bars, BUT now my tach doesn't work.  Thoughts on what I might have done to cause that?
  • MD
  • '89 Yamaha FJ1200, '94 BMW K75

Offline rbm

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Re: which throttle cable
« Reply #5 on: March 22, 2015, 04:53:38 PM »
Tach signal comes from the coil primary through a Black/Blue wire to Pin 16 on the instrument cluster.  Either of those connections got disturbed - the 1/4" spade on the coil or the multipin connector on the back of the instrument.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline dougrs

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Re: which throttle cable
« Reply #6 on: March 22, 2015, 05:02:58 PM »
I noticed that a vacuum tube (the one in the pic on the right side with the wire/spring around it) had come off. Everything worked once I put that back on.
  • MD
  • '89 Yamaha FJ1200, '94 BMW K75

Offline rbm

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Re: which throttle cable
« Reply #7 on: March 22, 2015, 05:06:39 PM »
Did you properly set up the TPS after you disturbed it?
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline dougrs

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  • Posts: 45
Re: which throttle cable
« Reply #8 on: March 22, 2015, 05:15:29 PM »
I forgot to mention, that I did take the TPS off again, and refit it too.

thanks for your help!
  • MD
  • '89 Yamaha FJ1200, '94 BMW K75

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