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Discussion Starter #1
I am having my '04 rear shock replaced with a Wilbers shock which can be hooked up to the hydraulic preload adjuster on the Wing. Wilbers says that the pump output on the Wing is too great and that the diaphragm in the pump needs to be moved up so that it will only travel 21mm. otherwise it will blow the seal on the shock. My question is how is this gonna affect the read out? Will it go from, say, 12 to 25? Will it go from 0 to 12? Is there a way to decrease the output of the pump without changing the readout? And what about the bank angle sensor on the shock. How will this figure into all of this? Thanks--Carl
 

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Not sure about the '04, but the '01-'03 rear shock is mechanical, not hydraulic or pneumatic.
 

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Sorry Chef but the rear shock on all Gl1800s is Hydralic with a electric pump that adds or subtracts fluid from the shock which adjusts the ride height. As to the question asked. Is the stock pump too strong for the new shock? I'm not sure I get your questions. Have not had any exp with this shock. Have you looked at progerssive suspensions shock? It will fully intergrate with the honda system. Good luck.
 

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There is probably a generic misunderstanding about what the Pre-Load Adjustor is and does. Making it simple the Pre-Load Adjustor is a seperate mechanism from the Shock and is only used as the top seat for the Spring. It can be placed in different positions on the Shock Body by simply machining a groove for the keeper circlip wherever you need to place it for a No Pre-Load position allowing for full movement of the Adjustor.

The Pre-Load Adjustor consists of a Pump that is operated by a DC Motor which provides Hydraulic Pressure on the Piston that is mounted on the Shock Body. The Piston has a hole in the center that the Shock Body fits through. When the Piston is secured in place over the Spring a Circlip Ring fits into a grove on the Shock Body to hold it in position.

When replacing the 970-lb/in OEM Spring on my OEM Shock with a 1,400-lb/in spring that was aprox. 1/4 shorter a local machinest cut a groove 1/4" lower on the Shock Body to allow for proper 0 Pre-Load position thus allowing me to maintain the full 0->25 settings on the Pump/Piston Pre-Load Adjustor.

If you need to change the position of the Pre-Load Adjustor Piston it is do-able provided you have enough metal on the Shock Body to work with.

Jerry
 

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Check out Works Shock

First of all, Works Performance already makes a replacement shock and spring for the GL1800 that will work with the existing system, with no modifications. I have one of their shocks on my bike, and it is a HUGE improvement over stock.

Second, yes you can alter how much adjustment you get out of the pre-load adjuster if need be. I have taken mine all apart and have posted photos here:

http://www.pbase.com/fredharmon/rearshock

However, I don't understand the statement
the diaphragm in the pump needs to be moved up so that it will only travel 21mm. otherwise it will blow the seal on the shock
Becase all the adjuster does is increase the preload applied to the spring. I don't understand how increasing the spring force would blow a seal in the shock. Maybe it couldn't handle the rebound dampening of the higher pre-load settings? But even so, I don't see how this would blow a seal.

Anyway, I suggest you call Works. They have a shock for the bike and it works good and you don't have to make any changes to the preload adjuster.

Fred H.
Fort Worth, TX.
 

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Here is a photo of the inerds of the GL1800 hydraulic/electric pump unit.

You will notice a connector (black) on the side of the units hydraulic chamber. If you look close, you will also see a small metal rod inside the chamber. This rod is moved up and down when the black plunger is driven up and down by the electric motor and angle/screw drive. It is attached to a variable resistor (rheostat) that lives under the black plastic connector. The controller unit measures the amount of resistance in the rheostat to determine the setting (number) to display on the controller panel. It is just a simple positional sensor similar to a Throttle Position Sensor.

The amount of travel is determined electronically inside the control unit on the fairing panel. It won't allow the motor circuit to activate when the sensor indicates 25, and conversely won't let it go any lower than 0. The easiest way to decrease the amount of travel provided would be to drain out some of the fluid. If done properly, you would induce enough air that the pre-load adjuster wouldn't begin to move until about the setting of 12 or so. This should reduce your adjustment range by about half.

Hope this helps. If you need more info, email me. I still think you should give the folks at Works Performance a call.

Fred H.
Fort Worth, TX.

 

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good infromation from jerry and fred......as usual

i agree with fred about calling works.....if an after market
part-of any kind-can`t be bolted on without modification
it is`t made for your bike....imo

i would go with a shock designed for a gl1800
 

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Works Shock

I now have about 10K miles on my Works Shock, doing both two up fully loaded, and single rides with no gear. This includes rides through the Arkansas and Missouri Ozarks all the way to Virginia and back two-up and loaded as well as a couple trips by myself loaded, and some day rides with no load.

This shock adds another dimension to the adjustment as the rebound dampening is adjustable. It also slightly affects the compression dampening as well. This is a nice feature as once you get the pre-load set properly, you then have the ability to add or subtract dampening force. With the stock shock, you are just stuck with whatever dampening it provides, which in some cases is not enough.

In the single rider/no gear mode, I run with the preload adjuster set at zero, and the rebound dampener set at 4 clicks from closed. In the two up/fully loaded mode, I run the pre-load adjuster at 10 and the rebound dampening at 6 clicks from fully closed.

The ride is greatly improved and the bike handles better in all aspects. Not only is the spring stronger on the Works shock (11,000 lb spring rate vs 875 lbs measured on my old OEM spring) but the shock is also better equipped to handle the compression and rebound dampening forces, and in addition, the shock is rebuild-able (unlike the stock shock). So in a few years I can send it back for a rebuild for about $100, instead of having to toss the shock and buy a new one. By the way, a new OEM shock for this bike costs around $1,000 because you can't buy just the shock, but you also have to buy the entire hydraulic pre-load adjuster as well (which is a dumb move on Honda's part).

After 10K miles, the Works shock shows no signs of wear and is still performing as well today as it did the day I installed it. The only thing I might have done differently is in the length of the shock. Works offered to make the shock slightly longer to increase my ground clearance, but I elected not to, as I wanted to evaluate the "standard" shock that would be offered to the GL1800 community. In hind sight, I have found that since I now run the shock at lower pre-load settings, that my ride height and ground clearance are slightly reduced. I used to run the OEM shock at 21/25 and hence it lifted the rear a bit and added some clearance. If I had it all to do over again, I would have asked them to make the shock about 1/4 of an inch longer (which translates to about an inch difference in ride height and clearance). This is also one of the nice things about Works, as their shocks can all be made custom to you (at no extra charge) with whatever changes to the spring rate, length, or dampening you need.

http://www.worksperformance.com/

Fred H.
Fort Worth, TX.
 

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Discussion Starter #10
Fred- Thanks for all the info. From what I understand, the output of the Gl1800 pump is too much for the Wilbers shock and needs to be decreased by removing some hydraulic fluid, advancing the piston and then refilling the pump and connecting the shock. The piston should only move 21mm to avoid blowing the seal on the shock. Does that make sense? My question was how to do this and what effect it will have on the 0-25 readouts. I am not a mechanic or engineer. My mechanic is doing this and says he will figure it all out. The Wilbers shock has a ride height adjustment on it which is why I went with this shock. It is very high quality and reasonably priced. A friend put one on his K1200LT and it absolutely transformed the ground clearance and handling of that bike. So my question again is how will decreasing the output of the pump affect the preload setting readout . Will the readout begin at lets say, 12 and end at 25 or will it begin at 0 and end at 12( or there abouts)? Is it the angle sensor that determines the readout? Wilbers doesnt address this guestion.
 

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Blowing a seal

Well, first let me say that I still don't understand the "Blowing a seal" statement. The pump drives a slave piston on the OEM shock that adjusts the spring preload. It does nothing to the shock itself.

I guess it could be that the Wilburs shock may use it's own pre-load slave cylinder that replaces the Honda OEM slave cylinder, and if that is the case, then maybe he is saying the pump will blow the seal on his replacement slave cylinder.

Anyway, how the unit reads after the adjustment depends on how the adjustment is performed. If he advances the adjuster to say 10, and then drains out some fluid, then the adjuster will only be able to go from 10 to 25. If the unit has no air in it, it won't be able to go to zero anymore as the pump motor won't be able to go past it's initialized point of 10. This could possibly present a danger of burning out the motor if you held the down button after the mechanism reached 10, because then the motor would be trying to draw a vacum on fluid, which is almost impossible to do. Of course all this depends on how the slave cylinder is mechanized. I am assuming it has a mechanical stop that won't allow it to retract beyond a certain point, and that this is the initial point that is being set to "10" on the adjuster. Trying to draw the slave cylinder back further against the stop would result in stress on the motor.

But if he simply lets the right amount of air into the system, the adjuster motor will still move from 0 to 25, but for the first 10 settings, the preload won't change, as the pump will only be compressing the air instead of moving the fluid. When I ran my OEM shock on my bike, you could hear the tone of the motor change at about number 4, because it had a bit of air in it. I refilled it and bled all the air out and now it begins moving from 1. Jerry had one that has so much air in it that the motor wouldn't labor until it hit about 10 or so.

Anyway, I hope this answers your question. Can you give me a link to the Wilburs shock site? I would like to see it.

Fred H.
Fort Worth, TX.
 

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Discussion Starter #12
Thanks again Fred. Wilbers does have a remote mechanical hydraulic preload adjuster that it comes with. I guess we could figure out the volume of hydraulic fluid that would fill the pump when the piston is 21mm from the outlet and add that much oil. Will discuss all this with my mechanic. With all the snowmobiles and quads that he has to deal with this time of year, I'm sure he is gonna be very amused and excited by all of this!! He is a super tech however so most likely this will all be a piece of cake for him. Try www.sebimoto-germany.de/ I got the shock with preload adjuster and ride height adjuster. Did not get the hi/lo compression adjuster. I did think about the Works but was concerned that it wouldnt increase the ride height which is the primary reason that I am jumping through all of these hoops. Regards--Carl
 
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