BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Phil C on 12 Mar, 2018, 16:12

Title: Throttle cable
Post by: Phil C on 12 Mar, 2018, 16:12
I've got problems with my throttle cable and twistgrip, and am embarrassed to say I don't know anything about them or how to adjust them. Should the item on the photo screw into the hole in the twistgrip housing?

Phil (novice.)
Title: Re: Throttle cable
Post by: AWJDThumper on 12 Mar, 2018, 16:58
The B40 throttle cable doesn't normally come with an adjuster fitted and so one must be fitted either at the carb end of the cable or the throttle end. The adjuster you've got slips over the inner cable and looks as though it should screw into the throttle where the cable enters. However, this depends on whether you have the appropriate throttle fitted to the bike. The alternative is to use an adjuster that screws into the top of the carb. If you haven't got one they can be obtained from AMAL/Burlen.
Title: Re: Throttle cable
Post by: JulianS on 12 Mar, 2018, 17:25
That is an adjuster which screws into the carb top.

Your carb top will either be threaded to take it, or if a plain bored hole will take a top hat ferrule.

See photo below, top carb top with adjusters and lower one showing the threaded holes.

The twistgrip usually takes a plain split top hat ferrule.
Title: Re: Throttle cable
Post by: Richard Mills on 12 Mar, 2018, 17:36
I've never seen an Amal carb cable adjuster with a longitudinal split in it. Owner modified?
Title: Re: Throttle cable
Post by: Phil C on 12 Mar, 2018, 18:54
I was wondering if it's some kind of modification by a previous owner. It was where the bare cable shows on the photo, the cable went inside it (via the slot) and the item slid up, threaded end first, into the twistgrip housing as per the route of the cable. But there appears to be nothing to stop it sliding down again. I don't get it. I guess the thread is redundant anyway. Could it be a spacer of some kind? What should be where the bare cable is?

Also, see other photo, isn't this the adjuster, about eight inches down from the twistgrip? If so, do I need more than just that one?

Phil (novice.)
Title: Re: Throttle cable
Post by: JulianS on 12 Mar, 2018, 19:59
Normally the twistgrip end of the cable will fit into a split tophat ferrule as in first photo.

With a mid cable adjuster, which is a much better idea that the fiddly hard to get at ones on top of the carb, you normally find a plain tophat ferrule (second photo) on the cable end to fits in the carb top.
Title: Re: Throttle cable
Post by: Phil C on 12 Mar, 2018, 21:05
Let me check that I understand.  The bottom end of my mid-cable adjuster should have a plain (ie not split) top hat ferrule on it, which pushes up into the adjuster?
Title: Re: Throttle cable
Post by: Phil C on 12 Mar, 2018, 21:08
Also, what kind of fit into the throttle housing should the split top hat ferrule be?
Title: Re: Throttle cable
Post by: AWJDThumper on 13 Mar, 2018, 14:55
If the throttle has a hole which is too big for the cable, and isn't threaded to take an adjuster, then it needs the split top hat ferrule which simply pushes into the throttle housing and is held in place by tension in the cable produced by the throttle spring. You don't need anything else.
Title: Re: Throttle cable
Post by: Phil C on 13 Mar, 2018, 17:27
Okay I guess the item I've got is a home-made top hat ferrule, but it's not held in place, it just falls off. Of course it could be me.
Title: Re: Throttle cable
Post by: JulianS on 13 Mar, 2018, 17:52
If you get the proper item it will be held in place by the cable.
Title: Re: Throttle cable
Post by: Phil C on 13 Mar, 2018, 18:02
Okay thanks, I'll try to get one.