Author Topic: Suspension Setting: More, or Less, Damping ?  (Read 3603 times)

Offline billincentraljersey

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Suspension Setting: More, or Less, Damping ?
« on: October 28, 2007, 11:34:13 PM »
I left the front and rear preload of my B1250 at stock settings.  I never got around to actually measure it.  Whatever it is, it seems fine.  I am about 175 lbs with all my gears on.

The problem is when I go over a single sharp bump, my a$$ gets a hard kick.  I notice the problem went away while I was on my cross country trip.  I had a top box mounted and had about 50 lbs of stuff in it.  Now I don't have the 50 lbs top box anymore, the kick is back.

So, do I need to increase the rebound damping ? 
Or, decrease the rebound damping ?
There is no compression damping adjustment, correct?
I think I need to decrease the COMPRESSION damping.
Carpe diem quam minimum credula postero
Bragging Rights:  NJ to CA in 8 Days on my B1250ABS. Not quite ADV Rider.
07 B1250ABS, 90 Kawasaki Concours, 84 Moto Guzzi V65SP, 77 Yamaha XS360, xx-77 NYC Subway

Offline pmackie

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #1 on: October 29, 2007, 01:11:15 AM »
Quote
I think I need to decrease the COMPRESSION damping.

yup...ideally you would DECREASE the "high speed" compression damping, but since you don't have ANY compression damping adjustment, all you can do is comprimise.

Since you felt it was better with more weight, you can DECREASE the spring preload 1 or 2 clicks AND decrease the rebound 1 click. This may make the bike wallow a little in the corners however.

The good news is that it is pretty easy to try more or less preload and/or damping. Check some of the other posts, because there are some links to how to set the correct sag/preload.
Paul
2002-GSF600S, Progressive Fork Springs, B12 Shock,
SS Brake lines, EBC HH pads, Leo Vince Ex & Kappa bags.
Ex Bike Mechanic (late 70's), somewhat rusty
32 years in the Fuel/lubes industry(Retired)

Offline rkfire

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #2 on: October 29, 2007, 09:15:47 PM »
I have a 1200, but I experienced the same thing. Any sharp edge bump, or washboard type bumps and the rear shock was harsh. I carry a passenger often, and I'm no lightweight myself so I increased the preload a click, and decreased the rebound adjuster just one click and it's actually a better ride. Even when riding one up it's a much better ride. Try the rebound, it can't hurt.

Offline billincentraljersey

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #3 on: October 30, 2007, 12:56:48 AM »
rkfire,

Thanks for your input.  I doubt I need to increase the preload, which will give me more compression travel.  I would need to do that if I am bottoming out when I hit the bump ... BUT, this kick in the a$$ went away when I carry a passenger or load up the rear with 50+ pounds of gear/luggage. 

I'll try the lower compression damping first.

Carpe diem quam minimum credula postero
Bragging Rights:  NJ to CA in 8 Days on my B1250ABS. Not quite ADV Rider.
07 B1250ABS, 90 Kawasaki Concours, 84 Moto Guzzi V65SP, 77 Yamaha XS360, xx-77 NYC Subway

Offline billincentraljersey

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #4 on: October 30, 2007, 01:01:20 AM »
Quote
I think I need to decrease the COMPRESSION damping.

you can DECREASE the spring preload 1 or 2 clicks AND decrease the rebound 1 click. This may make the bike wallow a little in the corners however.

hi pmackie,

wallow in the corner ... would that be from the decrease rebound damping or the decrease spring preload? 
Carpe diem quam minimum credula postero
Bragging Rights:  NJ to CA in 8 Days on my B1250ABS. Not quite ADV Rider.
07 B1250ABS, 90 Kawasaki Concours, 84 Moto Guzzi V65SP, 77 Yamaha XS360, xx-77 NYC Subway

Offline billincentraljersey

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #5 on: October 30, 2007, 01:04:02 AM »
Hummm ..... if I cannot resolve this suspension setting quirk, I'll have to ditch the skinny wife and find a fat girlfriend. :lol:
Carpe diem quam minimum credula postero
Bragging Rights:  NJ to CA in 8 Days on my B1250ABS. Not quite ADV Rider.
07 B1250ABS, 90 Kawasaki Concours, 84 Moto Guzzi V65SP, 77 Yamaha XS360, xx-77 NYC Subway

Offline rkfire

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #6 on: October 30, 2007, 10:34:42 AM »
I wasn't suggesting to increase the preload, I was saying that even though I stiffened my preload I STILL got a more supple rear suspension by decreasing the damping. I said "Try the rebound, it couldn't hurt".

Offline pmackie

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Re: Suspension Setting: More, or Less, Damping ?
« Reply #7 on: November 01, 2007, 02:55:46 AM »
Quote
wallow in the corner ... would that be from the decrease rebound damping or the decrease spring preload?

The downside of softer springs (less preload) and less rebound is that the bike will squat more due to sag, and rise more on the brakes, due to less rebound. So, basically on the way into the corner the back of the bike will rise. Once the apex is reached and the gas is applied, the bike will squat again, causing a "wallowing" response.

Both of these effects is fairly minor with just a change to the preload and rebound damping of the stock shock, but the effect is there even with the preload and rebound high on the stock shock. Obviously, more prenounced as cornering speeds become more aggressive.

A better shock tends to have better control of the "high speed" compression (usually bumps) vs the "low speed" (spring control).

I'm using a 1200 shock on my 600, which is better than the stock 600 shock, but still not as good as better suspension components. (the old cost vs performance compromise) :motorsmile:
Paul
2002-GSF600S, Progressive Fork Springs, B12 Shock,
SS Brake lines, EBC HH pads, Leo Vince Ex & Kappa bags.
Ex Bike Mechanic (late 70's), somewhat rusty
32 years in the Fuel/lubes industry(Retired)