Throttle play?

[Journeyman]

Hi folks. I'm a very new owner of an '82 GS450. One thing that's inhibiting my throttle/clutch control learning is the fact that my throttle has a large amount of play. Both rotationally and side to side. Probably about 15 degrees of rotation before it actually affects revs. I understand these are cable controlled. So, what do I need to do to eliminate both side to side and rotational play? I imagine the latter is just tightening the cable... Not sure about the former.

 

[Brendan W]

Are we talking about the twist grip at the bar ?
15 degrees doesn't seem excessive, could tighten it up to ten.
Most people talk about mm of slack in the cable,
The twist grip will have some end float.
Mine is at 2-3mm and doesn't worry me.
Nothing much to be done about it anyway as the flange on the twistgrip wears in the groove inside the switch housing

 

[Journeyman]

Yes indeed, the twistgrip. Maybe my degree guesstimation while I'm at work is off, I'd say it's probably at least 20mm, easily more. I'd like it to feel more precise and responsive and to bite earlier. Still can't figure out how the side to side play is solved. I'll have a look at the Haynes manual when I get home...
Anyone recommend some aftermarket stuff to aim at later?

 

[Brendan W]

The lower, carburettor end of the cable is locked with a nut. This is where to go for big adjustment. Fine tuning then at the top.
How much side play have you got?

 

[Journeyman]

Too much! 15mm, easy. It just feels....flimsy with that much play.

 

[Brendan W]

Open the switch housing and see what's going on in there. The twist grip has a flange at the inner end that should be a snug fit in the internal groove of the housing.

 

[Journeyman]

Thanks man, appreciate all the responses. I'll open her up when I get home today.

 

[TxGSrider]

I usually feel for slack with the bars turned all the way in each direction. I like there to be just a little play at its tightest (which is usually turned at lock the right). If I notice allot of difference in play I look to see that the cable is routed correctly.

 

[Guest]

Hi folks. I'm a very new owner of an '82 GS450. One thing that's inhibiting my throttle/clutch control learning is the fact that my throttle has a large amount of play. Both rotationally and side to side. Probably about 15 degrees of rotation before it actually affects revs. I understand these are cable controlled. So, what do I need to do to eliminate both side to side and rotational play? I imagine the latter is just tightening the cable... Not sure about the former.

I like to have as little slack in my throttle cable as possible, so I feel your pain. Be aware you must have some slack to allow for proper operation, but nothing like what you have. To find the minimum, tighten it way down and then start the engine and rotate the bars side to side, from lock to lock. If the revs increase anywhere while you are moving the bars around then you need more slack. The goal is to have the least amount of slack that still allows the bars to move fully side to side without affecting the revs.


Mark

 

[sam000lee]

You should have enough slack so that you can "feel" it in the throttle but from my experience there shouldn't be any more than that. By 'feel' I mean that with the throttle closed (i.e not touching it) you can put your hand on it and by applying a small amount of rotational wiggling feel when the cable tightens but before the butterfly valves in the carbs are opening (at least for the BS34's that are stock on the GS450).

If you look under the tank where the throttle cable is mounted by two nuts to the carb, the exposed cable should have a small amount of slack. Look at the latest post in the "Rebuild" thread in my sig. There's a (slightly fuzzy) picture that may (or may not) be good for reference/sanity check.