Bonneville America Forums Forums Technical Forums General Tech Throttle cables x 2?

Just in the process of stripping down my 04 TBA to fit the Wiseco 904cc kit when I noticed there are 2 throttle cables going to the carbs.
Anyone explain why is this? It appears one pulls and the other pushes..never seen that before.
Might need more help later and I will try not to lose any stuff in the crankcase..BikerThug!!

have u never seen before that 2 cables going from throttle cover on handle bars?

Yes I have..but never gave it much thought! Can you answer my question though? Why are there 2?

push and pull thats why is spring on carbs if something happens return cable closeing throttle

If you use just one throttle cable, you have to use Godzilla return springs to make sure the carb doesn't stick wide open.
The bigger the cylinders, the bigger this problem gets.
Heavy springs tend to wear your arm out on the highway.
Twin cables mean you can use light return springs.

I'll take a guess at this:

Since the metering function of the vacuum slide is dependent upon the butterfly opening the carb requires a more precise input from the throttle. The second (return) cable is more of a feedback control as opposed to a closing control to keep the operation consistent; this prevents any slack in the input cable and keeps the butterfly opening and closing motion smooth.

It's a government "safety" requirement. All bikes these days have a pull on cable, a pull off cable and a throttle close spring just in case something sticks or breaks and the rider doesn't know what clutches and kill switches are for.

Thanks guys..that answers my question. Didn't realise it was legislation.

Stephen, keep us informed with the process of the BB kit and photo's if possible mate, hope all goes well for ya. Also have a look here if you have not already done so