So I'm stuck.  The throttle cables in my 2018 Czech Sport Cruiser have begun to fray and need to be replaced.  I replaced them with the 1.5 mm throttle cable from Aircraft Spruce that says its "Ideal for Bing carbs" which sounded great since that's what the Rotax 912 ULS.  Unfortunately they did not work.  Turns out the Czech Sport Cruiser uses a 1 mm cable.  The 1.5 mm caused too much drag and the throttle return spring would not return to full throttle.

I purchased 1mm aircraft cable praying that would fix the issue.  Alas, it did not.  Even with these 1mm cables, there is still too much drag and the throttle won't return to full throttle.

I have no idea what type of cable Czech Sport Cruiser used because it is not in any manual and I can't find the information anywhere.

Do I just need to install a stronger return spring?  If anyone has any leads on where to get the slickest, smallest and strongest throttle cables, I am all ears.




  • Re: Throttle cable dragging

    by » 2 weeks ago

    Just to clarify, are you saying that with each throttle cable connected at the carburetor, and left disconnected at the throttle lever, the carbs won't return to full throttle? 

  • Re: Throttle cable dragging

    by » 2 weeks ago

    Some thoughts;

    New 1mm or 1.5 mm should make little if any difference, both are suitable.

    Drag/friction on throttle lever? - Jeffs question (above) addresses this.

    Routing problem? All bends must be gradual. No kinks/or sharp bends. The cable should , as far as possible, be aligned with the adjustment ferrule on the carburettor. This may result in using extra cable.

    Did you lubricate the cable? If so this could be the problem - modern throttle style cables have an inner sheath that does not like lubricant. 

    How did you adjust the cable length to suit application? - damaged outer sheath may be "grabbing" inner cable.

    Sign of cable in good condition; After cutting to length, hold cable assembly vertical - inner cable should slide/drop out of its sheath (outer cable) without/minimal assistance.

  • Re: Throttle cable dragging

    by » 2 weeks ago

    The throttle spring is supposed to go to wide open if the cable breaks and isn’t meant to while the cable is connected.

You do not have permissions to reply to this topic.