A spare Honda CRX throttle cable was used as they are of very good quality and would allow me to couple it up to the throttle pedal with ease and have a sturdy and reliable of adjustment.

The completed bracket.
 

 

A bracket was folded from sheet steel, with a brace welded on at one side. The other side was kept open to allow it to be easily fitted and let you view the linkage. The angle of the bracket was carefully set so the cable does not rub against the side of the end fitting - it exists parallel. If you do not pay attention to this you run the risk of wearing and ultimately snapping the cable - not recommended!

This bracket is fixed to the throttle bodies using the original fuel rail mounting holes, one of which was blanked and had to be drilled out and tapped to suit.

 

The only modification to the throttle cable was the removal of the dust boot to keep it from fouling on the linkage. The linkage on the bodies is made from aluminium and a couple of light casting marks had to be smoothed out using a needle file to let the throttle operate smoothly. Honda's car throttle cables are ever so slightly larger than the ones used on the Fireblade, but mine worked out perfectly in the groove, and the nipple on the end is even the same diameter so it just slots right in.

 

On most Honda cars they allow a reasonable length of free cable at the throttle end, and as my setup had very little free length I was going to have to loose the spare somewhere. It transpired that I only had about 40mm extra cable to loose. I decided to extend the rubber buffer fitted as standard around the cable with piece of strong rubber tube. This was cut down its length, slid onto the cable then covered over with adhesive lined heat shrink.

I could have just cut the cable and fitted on a screw clamp but didn't want the risk of it loosening so managed to retain the standard, cast alloy fitting after checking it was not being restricted on full throttle.

The only issue now was to look at the ratio, after all the bike bodies are designed to be used with a twist grip and not a pedal. All rigged up the throttle pedal in the CRX throttle pedal wanted around 8mm more movement than the throttle bodies allowed, which means the throttle pedal was not fully resting on its floor stop when wide open. This was modified by extending the stop so no undue stress would be put on the cable and bodies.

Because of the decrease in range over which the throttle travels from 0-100%, you loose a small degree of control - if this was a problem when driving the throttle pedal pivot point would have to be modified as the stock linkage on the bodies incorporates an end stop and balance adjusters between the body pairs and allows little flexibility for fabricating a conventional push rod style of linkage, and allow an adjustable ratio.

When testing the setup with the engine off everything felt very smooth, however when started the throttles were pulled closed by the engine vacuum and required a larger effort to open them, at which point the vacuum drops rapidly so the throttles move as normal, quite a challenge!

To get around this In the short term I fitted a heavier return spring on the throttle pedal so the force required to operate the throttle is at least even from 0-100%. This made a massive difference to the driveability of the setup, especially when driving in stop start traffic.