Throttle Cable Layout

[rjaxe]

Today I completed the modification I have been making to the throttle cable on my S130. In standard form the cable on mine was crunched down by the bonnet and depending on which way it decided to lie the throttle was affected. To be honest I was not impressed with the outer being the moving element in the arrangement rather than the conventional inner.
So I redesigned the arrangement so that the outer is fixed at both ends and the inner does the moving. The cable now lies almost flat over the right side of the engine. The carb lever is a redesign effectively turning it through 180 deg. so the inner is above the spindle an the return springs at the bottom. The outer fixed to a small bracket added the carb intake backplate. The cable itself has a lined outer and a hard fixed bend at the pedal box end. The pics below shows the installation.

[TonyWylde]

That looks a very well thought out tidy installation. I've wondered about the cable layout myself over the years. I might try and pinch your idea. Nice work.
Tony.

[stugilmour]

Excellent post Richard. Very timely, as trying to do something similar right now. I am expecting some eBay bits and bobs shortly. Can I pick your brain a bit on some details?

How are the ends of the cable outer sheath fixed to the brackets, or are they just fitted in place and don’t move as each bracket holds the outer sheath in place? Really confused with this detail and can’t find a simple piece that will attach the outer cable sheathing so it doesn’t slide around.

I am using bicycle brake cable material at this point. Any suggestions appreciated. Might have to use different cable materials?

I already have a similar 90 degree bend sleeve by the pedal box. Appears the bicycle guys call this a “noodle”, which is pretty descriptive. Does your noodle attach firmly to the pedal box?

I have ordered an adjuster sheath piece. My thinking was by adjusting the length the outer sheath will firmly remain in place without actually being firmly attached. Not sure yet if this will work?

Any help appreciated. Thanks

Stu

[rjaxe]

Hi Stu, for this design I used a throttle cable from a motorcycle, there are loads on EBay. I had to shorten it and add a purpose made nipple to the inner at the carb end where it fits into the trunnion (again purpose made). The outer sheath was fixed to the pedal box but the other end is just inserted into the adjuster on the carb backplate bracket, the lever return springs hold it in place. This is common practice on most bike installations. You probably have most of the details parts in hand by the sound of it but if you need to know exactly what I used let me know I will see if I can dig up the EBay references and the sketches I made of the manufacture parts.
I do not know what return spring arrangement you have in mind but I started with just the Weber internal springs which returned the spindle to its stop fine but it was so light that I could not feel any resistance through the throttle pedal so I added a pair of springs to the lever to stiffen it up the action. You can see the pair of springs in the photos.
It is a worthwhile improvement so let me know if you need more help.
Richard

[baileyman]

Very similar to what I did. I was worried about two things, the sudden rapid throttle opening, and the angular swing of the cable through the opening rotation. The first I cured by shaping an Euler spiral so the throttle opens slowly then fast instead of the other way around. The second (the actual topic here) I cured by using a small rose joint for the cable to pass through and hold the housing. With this the up and down movement of the cable can be accommodated without the cable bearing against a fixed housing fitting at either extreme. Subsequently when we bought a race prepped Seven I was pleased to see the same rose joint arrangement. John