Throttle sticking open
Discussion
Hi all, I've got a little problem that's surfaced lately - the throttles tend to stick open a little, which causes over-revs on gear changes.
I thought it was the cable but it's not.
It sticks just before the closed position, and then closes slowly the last bit.
I see there are springs on the ends of the throttle rods, plus I've got a spring across to the air box bracket, but I can't really increase its strength as it will make the accelerator too hard to push.
Any ideas please?
Thanks
Andy.
I thought it was the cable but it's not.
It sticks just before the closed position, and then closes slowly the last bit.
I see there are springs on the ends of the throttle rods, plus I've got a spring across to the air box bracket, but I can't really increase its strength as it will make the accelerator too hard to push.
Any ideas please?
Thanks
Andy.
This is a tricky one. There are five springs pulling those throttles closed.
One on each throttle arm, a coil going round the throttle arm.
One in each potentionmeter. Okay I know, picky's me middle name.
One big coil spring between the airbox bracket and the passenger throttle arm.
All the big 'I was going along and my engine redlined and wouldn't stop' are likely to be poor maintenance, as something has to have gone wrong with all of that. Unless of course the throttle cable doesn't break but seizes in its sheath.
Your problem is either the butterflies in slightly the wrong position.
The throttle shaft end being compressed by the screw plate at the cable end.
Or a slight bowing of the throttle shaft itself.
Disconnect the connection between both throttles. Take the big coil spring off and the inlet pipes. Screwdriver onto the throttle butterfly screws and crack each one open about a full turn.
Pick one throttle, open it slowly with your finger to about 30 degrees and then let it flick back closed. Do this a few times. It should now do this easily now without any sticking. Slowly tighten each screw and then presto, that bank should be back to normal. You've effectively shunted the butterflies back into an ideal position.
Two words of warning, don't whatever you do open the screws enough to drop one, and secondly you probably really ought to put some loctite on what you can see of the screw thread while doing it up.
Good luck
One on each throttle arm, a coil going round the throttle arm.
One in each potentionmeter. Okay I know, picky's me middle name.
One big coil spring between the airbox bracket and the passenger throttle arm.
All the big 'I was going along and my engine redlined and wouldn't stop' are likely to be poor maintenance, as something has to have gone wrong with all of that. Unless of course the throttle cable doesn't break but seizes in its sheath.
Your problem is either the butterflies in slightly the wrong position.
The throttle shaft end being compressed by the screw plate at the cable end.
Or a slight bowing of the throttle shaft itself.
Disconnect the connection between both throttles. Take the big coil spring off and the inlet pipes. Screwdriver onto the throttle butterfly screws and crack each one open about a full turn.
Pick one throttle, open it slowly with your finger to about 30 degrees and then let it flick back closed. Do this a few times. It should now do this easily now without any sticking. Slowly tighten each screw and then presto, that bank should be back to normal. You've effectively shunted the butterflies back into an ideal position.
Two words of warning, don't whatever you do open the screws enough to drop one, and secondly you probably really ought to put some loctite on what you can see of the screw thread while doing it up.
Good luck
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