This adjuster on #4 carb on GL1000 and GL1100 and on #3 carb on GL1200 is almost always sticky at the least and many times jammed solid.

If you try to force it, you can end up with the arm loosening on the bush. Sometimes a few drops of release oil will get it moving but often not.

The proper way to release it is to remove the spindle so that you can get at the bush, because from '76 onward there is a spring over the top of it.

Now please, you must try everything you can to get this thing moving first, as removing the spindle is a fraught operation.

Removing the throttle spindle.

Depending on the model, there will be a nut and spring washer on one end or the other of the throttle spindle.   If the nut is on the inside, between the #2 and #4 carb, you can pull the spindle out without dismantling the carbs, but if it's on the outside you will have to dismanlte the whole side as there is insufficient room between the carbs tio get the spindle out.

To remove it, use an adjustable wrench to stop the relevant operating arm moving and use an 11mm wrench to remove the nut.

Under NO circumstances whatsoever must you try to remove it by gripping the spindle.

The spindle is brass. First you will raise burrs that will rip the spindle bores if you don't remove them (or you will remove the plating on the spindle if you do), but worse, because this wrecks the spindle, you can actually twist it.

Now the two throttle plate screws need to be undone. This is where, if you don't have JIS screwdrivers, I suggest that you go and invest in some. These screws are soft and easily damaged.

They are also lightly peened over by the factory. 95% of the time they will come out and screw back in, but that odd time they will rip out the threads from the spindle! You will need to hunt up another carb body if this happens. I have tried to repair a damaged spindle but trust me, it doesn't work!

The plate will be a bear to get out. They almost always are, due to the fact of the screws compressing the slot. Drip some release oil around the plate before even thinking about removing it. I use a wood rod from the choke side to gently knock it out. Do not use anything harder than wood or you will damage the sharp edge of the plate.

You can now pull the spindle out, noting where all the plastic and steel washers go.

Now you can get at the adjuster to release it. Sometimes just a bit of heat will do the trick. An overnight soak in release oil may help. Be very careful not to use too much pressure on the arm that is attached to the brass bush. It can come loose on the bush and give you even more problems!

Replacing the spindle:

Grease the adjuster thoroughly and replace the spindle in reverse order. Lightly grease the sides of the plate to help it slide into place, making sure that the plate is the right way round (I suggest marking it with an ink marker before removal, as it is is only too easy to put it back the wrong way.)

Not that I have ever done that of course. No way! :oops:

Before you finally tighten the screws, hold the body up to a light source and check that the throttle plate is seating all round when closed. It is very easy to have it sit just slightly off and leaking. If you don't do this, you will be chasing a high idle forever.

The plate screws should be Loctited into place. I use Stud Lock, which is green; A bit stronger than Blue, not as immovable as Red.

Use a long screwdriver to gently peen them over again.

Spindle felt seals:

You should take advantage of the spindle removal to replace the 40 year old felt seals. Use a screwdriver and GENTLY lever the brass retainer out of the body. Remove what is left of the seals and clean out the seat area. Replace the new seal and GENTLY press the retainer back in. It's almost a finger push but not quite. I have a soft plastic mallet to finally knock it home. Whatever you use, take care, as these retainers are very easily distorted. Oil the felt seal before refitting the spindle. On the #1 and #2 bodies, oil the blind spindle hole while you have the chance.

New felt seals are available here.