Cable lengths - Quick action throttle

Anyone know what the front throttle inner/outer cable length difference should be for a Norton quick action throttle?

Just in the process of fitting one and the so called 'correct cable' I've just bought for a quick action throttle seems to be to short - Its got 60mm of inner cable protruding with the cable adjuster screwed fully in. This is not long enough and won't let the carb slides seat when its fitted.

At a rough guess I think the inner cable should be about 80 to 90mm longer than the outer for a quick action throttle. Can anyone confirm this before I return the cable for an exchange?

What twistgrip are you using Mike ? I have a twinpull Tommaselli Daytona 2C and made up cables for it. I'm not sure that it's quite as quick-action as some of the motocross styles with a huge drum. It needs just over 1/4 turn from closed to full throttle.

Off the bike, my cables have 112 mm free length with the in-line adjuster screwed in. Are you measuring with the slides connected ?

Does this help at all ?

Its the proper Norton one - part 064600 which is a single pull quick action throttle, with the front throttle cable I've bought - part 064601 to suit. The problem is it doesn't

I'm not certain what length the standard Norton front cable is as I'm changing from an Amal twistgrip (which is a different length cable to a standard Norton twistgrip) but I have a sneaky feeling the front throttle cable I have been sold is for the standard Norton twistgrip and not a quick action one.

The length quoted is with the cable off the bike and the adjuster screwed fully in. Also its about a quarter turn travel on the Norton quick action throttle, can't wait to try it - should be a vast improvement over a handfull and a half :!:

Mike
Had the same issue and had to shorten cable for a new AMAL twistgrip from Surrey cycles recently. The old Wassell quick action (1/4 T) from Norvil (my spare) has 82mm inner including nipple with inline adjuster screwed down.
Depends if you have an insert/ferrule at the t/g end. the Wassell used one, the AMAL doesn't and that increases the inner length needed by appx 6mm. Hope that helps.

Keith1069 said:

The old Wassell quick action (1/4 T) from Norvil (my spare) has 82mm inner including nipple with inline adjuster screwed down.
Depends if you have an insert/ferrule at the t/g end. the Wassell used one, the AMAL doesn't and that increases the inner length needed by appx 6mm. Hope that helps.

Click to expand...

Thanks for that one Keith - the lengths you quoted make complete sense.

I went to Norvil and we checked all the cables in stock and none suited the quick action throttle. The Norton part number for a quick action throttle cable turned out to be for the Amal grip I'd just taken off. (Thats Andover Norton stock for you - why do they use a Norton part number for something different instead of giving it a new original number???)

Eventually I bought the nearest cable Norvil had and modified the length so that 85mm of inner was available. Fitted it with insert sleeve and all now works fine.