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Throttle return
sambo83 - 20/3/09 at 11:15 PM

Also noticed after my throttle cable snapped that there's a return cable in a spring that is under mega pressure, before cable snapped my accelerator pedal was hard to push, is this normal or could it have caused the snap? Help appreciated!


mediabloke - 20/3/09 at 11:24 PM

quote:
Originally posted by sambo83
Also noticed after my throttle cable snapped that there's a return cable in a spring that is under mega pressure, before cable snapped my accelerator pedal was hard to push, is this normal or could it have caused the snap? Help appreciated!

I'd have thought it unlikely to be the cause, if the spring is between the pedal and the pedal box.
The tension in the pedal would be more likely to be due to the fibres in the cable fraying and jamming it, or to it having got snagged. Whereabouts (on the cable, not on the M6.. ) did it break?

Francis


sambo83 - 20/3/09 at 11:30 PM

Doesn't seem to have snapped so much as come out of the soldered nipple, the nipple is still stuck in the carb, it's just I've noticed how hard it is to move throttle by hand without cable and wondered if this is putting undue stress on the cable?


mediabloke - 20/3/09 at 11:42 PM

quote:
Originally posted by sambo83
Doesn't seem to have snapped so much as come out of the soldered nipple, the nipple is still stuck in the carb, it's just I've noticed how hard it is to move throttle by hand without cable and wondered if this is putting undue stress on the cable?

I see! I had a prob with a bike brake cable a while back; IIRC the crimped end being slightly loose and came off the end of the cable when I applied a bit too much pressure.

If your pedal is hard to press anyway, you're not going to be able to tell when the throttle arm hits its end stop. Good job the cable snapped...

I reckon if you get hold of a lighter spring for the throttle (or run it without for the moment) and replace the cable, you'll be laughing.

I have the opposite at the moment with the bike carbs on my Indy - the only pedal-return tension is supplied by the throttle arm. That causes the engine rpm to drop...eventually... Maybe we could start a 2-man group buy on throttle-return springs.

[Edited on 20/3/09 by mediabloke]


ReMan - 21/3/09 at 01:18 AM

You do need an extra return spring to comensate for the pedal rather than hand throttle on the bike
However some haeavy footed peeps over spring to make it feel more like a tin top
This is bound to add to the strain on the cable as is running without a stop
Lighten the spring, fit a stop, wear slippers job done


Slater - 21/3/09 at 08:52 AM

I have just had to fit a proper throttle return spring to my bike carbs, I used 3 elastic bands to get through SVA!

Here is my effort, I used a short cable with nipple, 2 x 5p coins with hole drilled in the middle, spring, big nipple on top.

I bought a big selection box of springs, the one in the pics seems the right sort of tension, but when I get it on the road I can easy swap for a stronger spring if required.

If you u2u me you address I will send you a selection of springs for you to try.
Keith

I also fitted a pedal stop (block of wood)so only 95% of throttle travel on the carbs is used.
This arrangement should ensure the cable is never stressed to much.


Throttle Return Spring
Throttle Return Spring


[Edited on 21/3/09 by Slater]


sambo83 - 21/3/09 at 09:06 AM

have got the nipple off this morn and clear evidence of previous breakage as nipple was drilled right through and remains of solder on nipple so it may have been a weak point! Will try halfords and a few bike shops today for some cable then will try to sort the prob! Cheers for your help


Hellfire - 21/3/09 at 09:09 AM

You definitely need to fit a stop for the accelerator pedal, to prevent overstretching the cable.

Phil


Paul TigerB6 - 21/3/09 at 09:28 AM

quote:
Originally posted by Hellfire
You definitely need to fit a stop for the accelerator pedal, to prevent overstretching the cable.

Phil


100% agree on this. Saves a lot of strain on the cable but even more importantly it stops your foot pressure putting strain onto the throttle mechanism on the carbs.

Did this job on a locost a couple of weeks ago. Two bits of L-shaped steel rivetted under the scuttle panel. This had a rivnut in it and then a socket head bolt. One in front of the throttle and one behind plus 5 mins adjusting the lengths of the bolt before locking off resticts the throttle pedal movement to ensure no strain in put on the throttle mechanism on the engine.


sambo83 - 21/3/09 at 06:48 PM

Ok gents went to local push bike shop near me and got a tandum brake cable that was 6 ft, cost £1:50. fitted and all working now, will def try and fit a pedal stop though!! Was really hard trying to fit pedal end though, at full stretch with one arm trying to tighten things, wish I was an octopus! Thanks for all your help. Still getting used to car and am still a little nervous of it but I'm sure will get used to it eventually.

[Edited on 21/3/09 by sambo83]


lococost - 23/3/09 at 10:01 AM

It sounds like you have the extra spring on the throttle side? If so, you'll put a lot of strain on the cable all of the time. Ideally, you want the spring on the pedal side, especially if it is that hard. (of course also get the throttle stop).

[Edited on 23/3/09 by lococost]