Suspension adjustment

[realwlrd]

There is a small adjustment knob on the right side, at the bottom of the rear monoshock. I cannot budge it. Any suggestions?

[Bruce C]

If it's a brand new bike, it's probably fully closed (clockwise). Mine was very tight. Use considerable HAND pressure counterclockwise.

Bruce C

[Caseyd]

When I first got my K1200GT I could not rotate that knob either, however I noticed if you put the bike on the center stand it makes the rear suspension easier to adjust. That knob has made a huge difference in the comfort of the bike for me.

[realwlrd]

Thanks guys. I did try the adjusment, counterclockwise, on the center stand, to no avail. I went to the dealer and he was able to do it on a used floor model with just his finger tips. I've sprayed some WD40 on it and tapped on it, still with no luck. I ridden it a couple of times since then and will try again in a few days. Maybe it will loosen up.

It seems like ther is some "slack" in the rear suspension, as if the bolts that hold the rear shock are considerably smaller than the holes they fit in. That's the sensation, anyway. Is that normal?

[rdfrantz]

realwrld, how about some information here.

 

Fill out your Profile.

 

What year and model motorcycle?

 

What country (The biked do differ by country)?

 

How many miles on it?

 

Purchased new by you?

 

Why didn't you have the Dealer attempt to adjust that "thingy", which controls rebound damping.

 

What is the setting of the Preload adjuster?

 

How much do you weigh?

 

What kind of riding are you doing?

 

What are you doing - specifically - when you noice "the slack" in your suspension?

 

Does it make any noise when you "do that"?

 

Does it act that way if you are stopped and bounce on the seat?

[realwlrd]

MasterYoda, thanks for the reply and here is more info

 

Fill out your Profile.

OK

What year and model motorcycle?

2004 K1200 GT

What country (The biked do differ by country)?

USA

How many miles on it?

7406 when I bought it on 10/10/2005. 7787 on 10/16. a little over 7800 now.

Purchased new by you?

used, bought it 10/10/2005. I am the 2nd owner.

Why didn't you have the Dealer attempt to adjust that "thingy", which controls rebound damping.

Because I don't trust dealers, I'm cheap and am capable of doing my own work. But I did ask there advice and they were indeed courteous and helpful

What is the setting of the Preload adjuster?

Slighty more than full soft. I did apply a 22 mm open end wrench (counterclockwise)to the knob and managed to break it free. It didn't take much, but it was more than I was able to mange by hand since I couldn't get a good grip on the knob

How much do you weigh?

No more than 240 lbs, full gear. about 180 lbs for the wife, full gear. We weigh 210 and 150, respectively, bare. We are tall, but not slender. We're definitely not short and fat.

What kind of riding are you doing?

Bought the bike for 2 up riding mainly. You can bet I will be using it solo, too. Prefer curves to slabs. Plan to ride the dragon Sunday. (done that plenty of times on my sportbike, with the wife)

What are you doing - specifically - when you noice "the slack" in your suspension?

Crossing surface irregularities, like bumps, cracks, joints.

Does it make any noise when you "do that"?

Not sure. I mostly feel it as opposed to hearing it. I suppose it would be a single "clacking" sound each bump, etc.

Does it act that way if you are stopped and bounce on the seat?

no

[rdfrantz]

Thanks for the details.

 

Overall, with your combined weights, past sport bike experience, and riding bent toward US-29, I'd say your were a candidate for upgraded spring shocks. Before Ohlin's, I'd recommend Wibers or Penskes, set up specially for you.

 

If I were riding my RS with my (like your) stock suspension, and weighted like you, I'd start the preload 3/4 toward stiff, and same with the rebound damping.

 

I'll guess your "slack", is a feeling returned by the rear damper where the spring is compressing and no damping is taking place, and then some damping is applied. Such would indicate the damping is already worn out, and as well, the stock unit is not at all up to the task anyway.

 

I'll warn you to INCREASE REAR PRELOAD RIGHT NOW. It only takes three or four events of bottoming out the rear damper before it ceases to function entirely.

 

Good luck with your investigation and solutions.

[JerryMather]

Here's a little more info. that a new friend of mine posted on another K bike site the other day.

Suspension setup

General rule for suspensions

Set the pre-load first (rider sag)

Check static sag

Set the rebound (if adjustable)

Set the compression (if adjustable...some even have both low-speed and high-speed settings)

 

Pre-load should be set such that the bike is sitting (at rest) at the 1/3 travel point from full extension (rear wheel off the ground) with the bike normally loaded (you included).

The K1200RS/GT rear travel is 6 inches (well, really 5.9+), so the pre-load setting should be 2 inches. I don't know what the suspension travel of the K-S or K-R is, but the pre-load should be set at about 1/3 of the full suspension travel.

 

Static sag...I can't remember the numbers, but it's more for getting the right spring than an adjustment. It has to do with how much the spring compresses in millimeters between a totaly unloaded to the bike (again, rear wheel up in the air) after the pre-load is set, and when the bike is at rest, unweighted by anything on the bike (no rider, no bags, etc). If the distance between the coils is small, the spring has basically been used up just by the pre-load, and indicates that a heavier spring is needed. If there's a larger distance (and again, I need to find the numbers), then you might need a lighter spring. However, after saying all that, most bikes come with a spring for a 160-180 lb/75-80k rider. If you normally have an additional 100lbs./45k weight on the bike, you should consider a different spring, and then you have the opportunity to have someone set the shock up per your specifications. Same if you are around 100lbs. dripping wet, but you also need to share your secret...

 

Rebound: When the shock returns from a compressed situation, adjust the rebound by decreasing the damping until it overshoots and returns to the normal rest point, then add damping until it stops at the normal rest point without overshooting. The object is to get the shock back to the normal rest point the quickest. Too little damping and it overshoots, taking longer to get to the normal rest point. Too much, and it's too slow getting to that rest point. A very slight overshoot would be ok, one that's barely noticible.

 

Compression is more of a user-feel adjustment. You don't want the suspension to bottom out (too little damping), but you don't want the bumps and jolts (too much damping) transmitted to the bike (and to you) if you can avoid it. Low-speed compression (0-2 inches/second) is for bumps and pavement irregularities, and the high-speed side (2 inches to 15 feet/second) is for potholes and badly maintained railroad grade crossings. Low-speed is something you can play with over time riding various roads. Good place to start is the mid-range setting, and based on the feel, adjust as you like. Don't go more than two clicks at a time, though. If you end up with the adjustment at one end or the other, it could be time to have the shock rebuilt and set-up for you by a suspension shop The high-speed circuit should be adjusted fairly close to the same setting as the low-speed one, then on or two clicks one way or the other depending on your "large-bump" experiences. Hopefully, you don't have those.

__________________

Ray

[realwlrd]

Thanks everybody for your replies.

I did adjust the preload and damping to the max and then backed off slightly. Rode about 120 miles with the wife along highway 70 between Knoxville and Crossville, TN and back. Much improved handling, I must say. Sunday, did a solo "Toy's for Tots" run with the local Hardley crowd (about 8,000 bikes). Not much of a test. Then went to the dragon. Thought the suspension worked great, full stiff. Handles amazingly well for a big bike, but then I'm no Valentino Rossi, either. I was a little wonky on the throttle control at first. Quite a bit more engine braking from a 1200 cc motor than with a 600 cc. Prefer to stay off the brakes as much as possible on 129. But got the hang of it about half way through going up. Not a problem coming back due to slow traffic (van) in front. All in all, I am more than happy with the bike. So is the wife. Bless her little pea-pickin' heart. As much as I loved having her with me on the sportbike, I know it was tough on her. No more back aches for her.

 

I reckon the slack is as your say, Master Yoda. Rebound damping, but no compression damping, right? Not so much a problem, as a quirk. I have looked at the Wilbers (after seeing it recommended in this forum) and have a quote in hand. (yikes)

 

Beav, thanks for the suspension refresher. One of the better ones I have seen. I will use that info as a guide for new suspension parts.