Why I dread changing fork oil

[Pharkmeh]

You guys rock!

bloody big ditto - thx for another keeper....:-D

[Jethro]

Mark, what does the 1100E have for rear shocks? I did a cheap pair of MDI shocks and even they are an awesome compliment to the progressive fronts. Such an upgrade over the stockers. Enough so that I am considering a pair of Ikons or maybe even Works jobbies.

[Hoomgar]

Mark, what does the 1100E have for rear shocks? I did a cheap pair of MDI shocks and even they are an awesome compliment to the progressive fronts. Such an upgrade over the stockers. Enough so that I am considering a pair of Ikons or maybe even Works jobbies.

I believe they are stockers. What should I look for? I have S&W air shocks. Should I try them or just spend the cash and get progressive rears too? So far the rear don't seem to bad.

[bwringer]

Here's a dumb question... Maybe Mark can help.

On my GS1000, there is no obvious nut ion the top of the forks, just the air valve. So how do you take 'em apart? My fork seals just came in.

Also, you might want to loosen the top pinch bolts. This makes it MUCH easier to remove the fork caps. Just don't forget to tighten them again.

[bwringer]

Thanks for all that Brian. Now as for this quoted statement? (Dynamic Sag) What is that?

You might notice that the black zip tie stays on one leg of my bike's forks. The idea is that you see how much of the fork's travel you're using over a given stretch of road or track, which might provide useful information for further fine-tuning of your suspension or possibly an alteration of your riding style or position. It's just one more piece of information you can add to all the other information and impressions you gather while riding.

Let's say you move the zip tie to the bottom while relaxing and chatting at the overlook at the north end of Deals Gap.

After your record-setting run to the resort, see where the zip tie ended up and ponder this information carefully.

If, for example, you feel that you're chattering under hard braking, the humble zip tie can verify whether the fork is indeed bottoming out under hard braking and you can then decide whether you want to increase preload or spring rate (assuming higher-rate fork springs are available.). If you're not bottoming, but you're still chattering, you might look into stabilizing things, maybe with a fork brace, or you might try decreasing preload a bit or using lighter fork oil. Of course, lighter fork oil would affect damping everywhere else... it's a balancing act.

You might also decide that increasing preload would make the fork too stiff on corner exits, so you can decide to instead alter your riding a bit (brake more gradually) rather than sacrifice compliance. (Regular maximum braking is not a safe tactic for street riding anyway.)

On the other end of the spectrum, your zip tie might tell you that you're not using all or most of the available fork travel during hard riding. In this case, lighter preload might give you better feel and compliance. Or you could take this information and decide it would be safe to brake harder heading into turn #4 on the track, or you might decide to change your body position a bit to move more weight to the front on corner exits.

Basically, the maximum amount of fork travel you're using while riding (dynamic sag) is a piece of data you can add to a complex equation, and it can have many different meanings and results. You can also put a zip tie on the shaft of one of your rear shocks to gather similar data.

Most people who worry about such things are track riders running consistent laps and looking for that last 1%. For 99% of riders, simply setting static sag will give them amazing improvements in control, performance, and comfort. Very, very few riders, even on modern sportbikes, have ever bothered to set static sag properly.

[Hoomgar]

The scary part is I understood all of that and it makes perfect sense to me :shock:

Thanks Brian, now you have given me even more things to "over-think" about

I'll be using this info.

[Sandy]

I use the zip tie method all the time. It really takes the guess work out of suspension tuning. I find, however, I get a better visual reference by using one on each fork leg, one set where the suspense would actually bottom out and one to use to measure suspension travel. Hoomie, on my naked GS1000 with progressive springs I've found that a 5/8" inch preload spacer, 15W fork oil and no air works great for me at 210lbs. I've got 1 1/4" preload and come to about 1" of bottoming out under very hard braking. This setup works good for me and performs well for what I would call moderately aggressive riding on rough roads, what ever that means! Maybe use this as it start point for your setup.

[Hoomgar]

I use the zip tie method all the time. It really takes the guess work out of suspension tuning. I find, however, I get a better visual reference by using one on each fork leg, one set where the suspense would actually bottom out and one to use to measure suspension travel. Hoomie, on my naked GS1000 with progressive springs I've found that a 5/8" inch preload spacer, 15W fork oil and no air works great for me at 210lbs. I've got 1 1/4" preload and come to about 1" of bottoming out under very hard braking. This setup works good for me and performs well for what I would call moderately aggressive riding on rough roads, what ever that means! Maybe use this as it start point for your setup.

Thanks Sandy. I'm working on an 83 1100 though but the same school of thought applies. Where have you been hiding my friend!?

[Billyboy]

I use the zip tie method all the time. It really takes the guess work out of suspension tuning. I find, however, I get a better visual reference by using one on each fork leg, one set where the suspense would actually bottom out and one to use to measure suspension travel. Hoomie, on my naked GS1000 with progressive springs I've found that a 5/8" inch preload spacer, 15W fork oil and no air works great for me at 210lbs. I've got 1 1/4" preload and come to about 1" of bottoming out under very hard braking. This setup works good for me and performs well for what I would call moderately aggressive riding on rough roads, what ever that means! Maybe use this as it start point for your setup.

Thanks for the info Sandy! It turns out that I ordered progressive springs in MAY and they just got in. I guess I forgot I ordered them. I've also ordered fork seals, and euro bars from Bikemaster. I'll be doing it all in one shot when the stuff gets in.

I got ten pounds on you and like to use the springs, so I might use a 3/4 " spacer.

Is there a thread on replacing seals?

[Sandy]

Thanks Sandy. I'm working on an 83 1100 though but the same school of thought applies. Where have you been hiding my friend!?

Been hiding just about everywhere but home Mark. Family reunion and a trip to Vancouver Island took up about 12 days, back to work for 4 days, then off to a another reunion my wife arranged with her retired nursing buddies, bush camped for 5 days and had a big lightning storm/wind storm and had to cut our way out of our campsite. People nearby had their car totalled with some trees that came down and luckly nobody was hurt. Life never gets dull. Thanks for asking though. Maybe I'll be around a little more now. Maybe I'll even get to ride my GS a bit.

[Billy Ricks]

One thing to keep in mind is if once you get preload set to the desired amount of sag for your weight, if you bottom out you need stiffer springs. More preload at that point isn't the right way to go.

[8trackmind]

I got ten pounds on you and like to use the springs, so I might use a 3/4 " spacer.

Depending on your progress with the wheelies, you may need an even larger spacer.

[Billyboy]

Depending on your progress with the wheelies, you may need an even larger spacer.

Yeah, good point. Hmmm. And my Euro bars just shipped. That'll put more weight up front. I may need to start with a full inch and experiment until I stop slappin the tank.

[bwringer]

One thing to keep in mind is if once you get preload set to the desired amount of sag for your weight, if you bottom out you need stiffer springs. More preload at that point isn't the right way to go.

True, but where are you going to find a selection of spring rates to fit skinny old GS forks? AFAIK, they simply aren't available. Maybe there's someone that makes fork springs for vintage racers or something.

At least with progressive-rate springs, the spring rate does go up as the spring is compressed. So with more preload, you do use a higher spring rate. The problem is, the whole process is pretty imprecise and choices are severely limited by the availability of different fork springs.

With that said, upgrading to Progressive brand fork springs and shocks, along with taking some care in setting sag is about the biggest performance bang for the buck possible. (Progressive brand stuff is the least expensive suspension upgrades option, and is plenty good for most GS riders.)

As many have remarked, just getting the suspension in the ballpark transforms a GS. An old rattly antique suddenly handles surprisingly well. Even if you're not a corner carver, the improved feel, precision, safety, and comfort are amazing and well worth a couple hundred bucks and an afternoon in the garage. A skilled rider can keep up with modern bikes all day -- the bike stops being an obstacle.

Of course, there are intrinsic limitations to those skinny forks, flexible frames, and heavy engines. The laws of physics still apply, but decent suspension can help you bend the rules a bit...

[Billy Ricks]

Either using springs from a heavier bike or calling suppliers will yield heavier than stock springs. As long as they aren't too long for the forks they can be adapted with preload spacers.