Bike Carb Throttle Cable?

[brainbug007]

Can anyone describe (with pictures :)) how I connect a throttle cable from my bike carbs to the pedal box? Also will the throttle cable out of my donor work or is there something more specific I need?

[davedew]

To connect the throttle of my bike carbs I used a bicycle gear change cable. It already had a moulded on nipple at one end, I bought a solderless nipple for the other.

I drill through a bolt which was screwed into the back of the pedal box to hold the cable outer.

http://i831.photobucket.com/albums/zz233/davemdew/Haynes%20Roadster%20Pictures/Chassis%20Assembly/SAM_0300.jpg

I then had a friend make a fitting to attach it to the pedal. This is able to rotate in the pedal.

http://i831.photobucket.com/albums/zz233/davemdew/Haynes%20Roadster%20Pictures/Chassis%20Assembly/SAM_0306.jpg

The carb end outer is then fixed in a cable adjuster, with the nipple fitted to the carbs. I used an extra spring to get a bit more positive action on the throttle closing as I found it a bit lazy.

http://i831.photobucket.com/albums/zz233/davemdew/Haynes%20Roadster%20Pictures/Chassis%20Assembly/SAM_0301.jpg

HTH

Dave

[brainbug007]

That does help loads thanks dave :) Few questions though:

On your 3rd picture showing the cable attached to the carbs, are those all just bolts with the center's drilled out like in your 1st picture?

What size bolts did you use and drill the holes in them to?

Again in your last picture, I take the cable coming off the carb on the right side (without the spring) I take it this goes down to the pedal box? How did you route it? Does it just go straight down at a 180 degree?

[davedew]

Hopefully you can see the route in the below picture.

http://i831.photobucket.com/albums/zz233/davemdew/Haynes%20Roadster%20Pictures/Chassis%20Assembly/SAM_0298.jpg

On the carbs the cable seats in a proper cable adjuster. All the others are ordinary bolts just drilled through. I think from memory they were 6mm bolts with a 3mm hole to suit the cable.

[brainbug007]

Ah cool that helps to see the route. Next question being where'd you get the spring from and what size/desc was it? Also any ideas if there's an off the shelf version of the thing that goes on the pedal that your mate made?

[brainbug007]

Did some digging (probly should have done that 1st really..) but I guess its a "compression" spring that i want, so one of these? 6mm od, 4.83 id, 19mm free, 4.7mm compressed?

http://www.ebay.co.uk/itm/Compression-Spring-6-1-x-4-83-x-19-05mm-/150644685111?pt=UK_BOI_Metalworking_Milling_Weldin g_Metalworking_Supplies_ET&hash=item23131f7937

[davedew]

The spring was just one I found at work, but you need to make sure they are long enough to allow for the amount the throttle moves. I would say 19mm free length is to short. Mine is probably double that.

Plus the bolt has to go inside the spring so you want at least a 6mm I/D spring

[brainbug007]

Ok I'll keep digging for a longer and slightly wider spring. for the cable do you think one of these would be adequate?

http://www.ebay.co.uk/itm/Fibrax-Inner-Outer-Teflon-Coated-PTFE-Bike-Gear-Cable-Cycle-Wire-/180754326183?pt=UK_sportsleisure_cycling_bikeparts _SR&hash=item2a15cc22a7

[davedew]

That's the sort of thing I used.

[brainbug007]

Cool, found a better spring off the same person. Much larger compression range and i'll just have to use a larger M8 bolt at the top.

http://www.ebay.co.uk/itm/Compression-Spring-12-19-x-8-9-x-38-1mm-/150551258540?pt=UK_BOI_Metalworking_Milling_Weldin g_Metalworking_Supplies_ET&hash=item230d8de5ac

[davedew]

Should work fine. I think if you look at the picture of the carbs then the bottom bolt is M6 with a washer to locate the bigger spring. The bolt at the top of the spring is an M8