GL1800 (2009) harsh front suspension

[coolboot]

I changed the bushings and spacers on my front suspension
I cleaned all parts
I dismounted the anti-dive valve and cleaned it.
I used a 1/4 dr socket to push the anti-dive piston (using a clamp) to reinstall the locking ring
Cross-torqued screws as per specification

For refilling the forks, I used the recommended oil: Pro Honda Suspension Fluid SS-8 (10W)

As per the service manual (I own it):

I added 17.9 US oz on LH fork and 16.4 US oz on RH fork
I slowly pumped the fork tubes serveral times to remove any air
I compressed the fork tube fully
I measured the oil level from the top of the fork tube
The fork fluid level specification is 5 inches (spring and the long spacer NOT installed)

The oil level was too low, so I added oil to match the specification

My questions are:
1. Was it ok to add oil since its level was not up to the recommended height?
2. OR should I have kept the oil qty without going further?

To me it's confusing since I don't know if it is possible to match the oil qty AND the oil level height.

3. What do you believe is causing the harsh suspension (my tires are at the correct pressure)?

[WingAdmin]

The oil height in the forks is what matters. If you have both measurements available to you, go by the height. The quantity can vary depending on how much oil was left in the forks, etc.

Make sure to pump them up and down to make sure all air bubbles are out, and re-check the height just to be sure.

[MikeB]

I dismounted the anti-dive valve and cleaned it.

Many Honda GL1800 owners have had problems with the anti-dive unit sticking and causing front-end problems.
The brake slave cylinder may be the problem, it forces a 5mm pin into the anti dive actuator to lock up the left fork during braking. This slave cylinder is supposed to return upon releasing the brake lever but it doesn’t always behave as it should, it can take some time to return to its resting position.

Take a look at this site and read through the posting. Good information there.
http://www.goldwingfacts.com/1800antidive.htm

[coolboot]

Thanks for the useful information.
Is there a way to test the antidive valve operation?

[MikeB]

I believe if you want to see how it feels just unbolt the anti-dive actuator on top of the anti-dive valve, tie it up somewhere that it won't mark anything up and go for a ride.

Take a look at the Fred Harmon site for a very good explanation of the Anti-Dive valve.
http://www.pbase.com/fredharmon/antidive

[Red Ron]

Thanks for the useful information.
Is there a way to test the antidive valve operation?

you can do the nickel trick and check to see if there is any difference. Very easy to do. Drill a 7/32" hole in the exact middle of a nickel and put it between the two halves of the anti dive. For the '08 i used to own the difference is incredible. It only costs a nickle and easy to reverse.

[Viking]

Thanks for the useful information.
Is there a way to test the antidive valve operation?

you can do the nickel trick and check to see if there is any difference. Very easy to do. Drill a 7/32" hole in the exact middle of a nickel and put it between the two halves of the anti dive. For the '08 i used to own the difference is incredible. It only costs a nickel and easy to reverse.

And if you do not like to use nickels to do this trick, you can buy a kit from here for $16.99. Gives you a shim, and slightly longer installation screws.

http://www.motomfg.com/GL1800_Goldwing_ ... p/gl-1.htm

[MikeB]

I like the nickle idea if the intention is to disable the Anti-Dive. You can't hardly buy a washer of that size for a nickle.

[Big Blue UK]

I disabled the anti dive, also the linked braking, nice if you are riding around on dry roads resembling a snooker table. If I only want to apply the rear brake, I do not want anything applying the front brake for me, same when I apply the front brake. As for locking up one of my fork legs for me while braking, no thanks.

How many 1800's have you rode to compare the difference, your front end may be as good or the same as the next, could be that you prefer a softer ride.

I bought the kit Viking linked to.

[coolboot]

I don't need to compare with other GL1800 at this point.
Mine is so stiff with a hard rebound that it is hazardous to get out of control.

[Viking]

I don't need to compare with other GL1800 at this point.
Mine is so stiff with a hard rebound that it is hazardous to get out of control.

In that case, there is a problem. What amount of pressure is in your front tire. Some of us run as high as 43, which is pretty hard, but most don't. It is possible that you did actually get too much oil in the forks. The only solution is to open up the top caps again and suck some out, but this does not give you any exact measurement of what is actually in there. This, however, should not cause hard rebound, only hard compression. If you have too much fluid in the forks, you are going to blow your new seals out. Another thing you may try is to loosen off the pinch bolts and the axle nut and then bounce the front end to see if it loosens up. If it does, then you have experienced what is called 'stiction' where the forks are binding due to being slightly twisted. If this works for you, then retighten the axle nut first, then torque the pinch bolts to exactly 16 foot pounds and no more. Stiction normally shows itself as poor rebound, but could also make the front end hard, I guess. If you do not have a stiction problem, then you must have excessive oil in the forks. GL1800s suffer from too soft a front end, not too hard.

One other thing. Temporarily disabling the antidive could verify that it is not the problem.

[WingAdmin]

I don't need to compare with other GL1800 at this point.
Mine is so stiff with a hard rebound that it is hazardous to get out of control.

In that case, there is a problem. What amount of pressure is in your front tire. Some of us run as high as 43, which is pretty hard, but most don't. It is possible that you did actually get too much oil in the forks. The only solution is to open up the top caps again and suck some out, but this does not give you any exact measurement of what is actually in there.

Sure it does. In fact, that's the best, most accurate way to measure the correct amount of fork fluid.

Take a small metal pipe or stiff hose. Measure from the end of it exactly 5 inches or 128mm (which is the correct fluid level for the GL1800). Mark the pipe, or put a piece of tape around it to mark that level. If it's metal, you could bend it.

Remove the top cap, insert the pipe so that it reaches exactly 128mm down into the fork. Now use a small pump (Mity-Vac works great) to suck up the fluid through the pipe. If it doesn't suck any up, add some fluid to the fork. Once it has sucked up fluid and then stops sucking up any more, you know the fork oil level is exactly right.

Fork Fluid Level

[thrasherg]

Sure it does. In fact, that's the best, most accurate way to measure the correct amount of fork fluid.

Take a small metal pipe or stiff hose. Measure from the end of it exactly 5 inches or 128mm (which is the correct fluid level for the GL1800). Mark the pipe, or put a piece of tape around it to mark that level. If it's metal, you could bend it.

Remove the top cap, insert the pipe so that it reaches exactly 128mm down into the fork. Now use a small pump (Mity-Vac works great) to suck up the fluid through the pipe. If it doesn't suck any up, add some fluid to the fork. Once it has sucked up fluid and then stops sucking up any more, you know the fork oil level is exactly right.

Fork Fluid Level.GIF

This is the way I have always done my forks and I believe it to be very accurate, you must make sure the fork is fully compressed when you run the test and should have pumped the forks a few times before performing this test to get any air out of the damping mechanism.

Gary

[Viking]

Sure it does. In fact, that's the best, most accurate way to measure the correct amount of fork fluid.

Take a small metal pipe or stiff hose. Measure from the end of it exactly 5 inches or 128mm (which is the correct fluid level for the GL1800). Mark the pipe, or put a piece of tape around it to mark that level. If it's metal, you could bend it.

Remove the top cap, insert the pipe so that it reaches exactly 128mm down into the fork. Now use a small pump (Mity-Vac works great) to suck up the fluid through the pipe. If it doesn't suck any up, add some fluid to the fork. Once it has sucked up fluid and then stops sucking up any more, you know the fork oil level is exactly right.

Fork Fluid Level.GIF

This is the way I have always done my forks and I believe it to be very accurate, you must make sure the fork is fully compressed when you run the test and should have pumped the forks a few times before performing this test to get any air out of the damping mechanism.

Gary

Yeah, I must not have explained myself very well. I was under the impression the OP had already done all this, and so had the exact right amount of fluid --- so --- if he removed some fluid from the forks, he would no longer be able to ascertain how much fluid was in the forks. This was only a test to see if the forks soften up a bit. I do believe, tho, that the problem is not the amount of fluid, which is reported to be correct. My first thought would be the AntiDive, and the second would be stiction.

[zgoldwingman]

I changed the bushings and spacers on my front suspension
I cleaned all parts
I dismounted the anti-dive valve and cleaned it.
I used a 1/4 dr socket to push the anti-dive piston (using a clamp) to reinstall the locking ring
Cross-torqued screws as per specification

For refilling the forks, I used the recommended oil: Pro Honda Suspension Fluid SS-8 (10W)

As per the service manual (I own it):

I added 17.9 US oz on LH fork and 16.4 US oz on RH fork
I slowly pumped the fork tubes serveral times to remove any air
I compressed the fork tube fully
I measured the oil level from the top of the fork tube
The fork fluid level specification is 5 inches (spring and the long spacer NOT installed)

The oil level was too low, so I added oil to match the specification

My questions are:
1. Was it ok to add oil since its level was not up to the recommended height?
2. OR should I have kept the oil qty without going further?

To me it's confusing since I don't know if it is possible to match the oil qty AND the oil level height.

3. What do you believe is causing the harsh suspension (my tires are at the correct pressure)?

I'm pretty sure the right fork which has the cartridge, the piston in the cartridge, the threaded rod has to be bled of the air trapped in the cartridge. I always pump it full travel about 10 times. Helps to tie a wire or string below the nut to pull up.