Author Topic: Past-my-Prime Shock Thread  (Read 275 times)

Offline Past-my-Prime

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Past-my-Prime Shock Thread
« on: July 19, 2019, 08:16:32 PM »
OK so I'm going to ask a really dumb question.

How do you know when your shock/spring is bad?

Mine is 30 years old. Going over speed bumps feels a bit harsh (I have mine set at the middle setting, and I'm only 155 lbs so that might be a problem).

But it does not bottom out, nor does it wallow as in up-down-up-down after a bump.

I've made a commitment to doing some long neglected maintenance on this bike (who I've just named after 23 years of ownership as Rocinante btw) and after coolant flush, brake fluid flush, gear box fluid change, new spark plugs, oil and filter change, valve clearance check, and spline lube, the suspension will be the next thing I'm looking at. I sprayed the dreaded 4-connetor under the fuel tank with electrical contact cleaner while I was draining coolant and had to move the fuel tank anyway, but she doesn't seem to run any better. I'm getting off topic. . .

Honestly she still rides like a bat out of hell despite the heavy weight full fairing and I have a very strong attachment to her but I don't want to just replace pieces because they're old.

Oh, regarding the Z-hose, I checked and there are cracks all over. I can't believe I have no issues with idling, dying, etc. but I've ordered a replacement.

FOCUS!  Is there a way to know when you need to replace the springs and shocks?
  • North Shore of Lake Superior
  • 1989 K75 RT

Offline daveson

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Re: Past-my-Prime Shock Thread
« Reply #1 on: July 20, 2019, 05:04:16 AM »
 "Going over speed bumps feels a bit harsh.

But it does not bottom out, nor does it wallow as in up-down-up-down after a bump.

 I don't want to just replace pieces because they're old."


If it's OK, keep riding, don't replace it.  Put it on the softer setting if it feels too harsh and see how you like it.

If the shocks no good it's bouncy,  if the springs no good it's compressed (the free length and the compressed length will be shorter) so the bike would be a bit lower. But it can't be too bad cause it doesn't bottom out.
  • Victoria, Australia
  • Current;'86 K100RT Past; '97 Yamaha V Star 650 Yamaha V Star

Offline johnny

  • TrailBrakingThrottleWhacker
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  • Whacking...n...Chopping Sliding...n...High Siding
Re: Past-my-Prime Shock Thread
« Reply #2 on: July 20, 2019, 08:52:48 AM »
greetings...

bricks needered new shocks when they rollered outta the factory...

do yourself a flavour and getts a new shock on there... not icon of course...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Laitch

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Re: Past-my-Prime Shock Thread
« Reply #3 on: July 20, 2019, 09:27:48 AM »
Is there a way to know when you need to replace the springs and shocks?
When you can't adjust your way out of an unsatisfactory rear shock response even after consulting with those who have skill in such adjustments.
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Past-my-Prime

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Re: Past-my-Prime Shock Thread
« Reply #4 on: July 20, 2019, 10:04:43 AM »
When you can't adjust your way out of an unsatisfactory rear shock response even after consulting with those who have skill in such adjustments.

Thank you!!

The only unsatisfactory thing right now is a bit harsh on speed bumps. To adjust to that, I only need to go slower on the speed bumps.

However. . . I'm heading out to the shade tree where I do my wrenching and such, and the next thing I'm going to do is set the rear spring to a softer setting.

I will provide an update to any popcorn-eaters.

What I have learned so far on this site (beyond all kinds of horror stories of breaking motorbricks and then -- usually -- fixing them) is that Johnny likes to go fast and uses a lot of Techtron, Martin and Laitsch are quick to advise people asking questions to do your research first and consult the Lieberry, Frankenduck has a bunch of step-by-step instructions on how to do almost anything, and Inge knew everything there was to know about K-bikes. There's more but I have some stuff to do.
  • North Shore of Lake Superior
  • 1989 K75 RT
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Offline The Mighty Gryphon

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Re: Past-my-Prime Shock Thread
« Reply #5 on: July 20, 2019, 10:21:25 AM »
Re: Speed bumps

Realize they are a Fascist attempt to provide real time punishment for your disregard of posted speed limits.  They are intended to provide a harsh whack at your backside similar to what your dear mother may have given you when misbehaving in the supermarket. 

There is a short stretch of road with a corduroy surface where heavy trucks have to stop for a signal.  That is my test area for suspension settings.  If you can find one like that(usually near a gravel pit, mine or concrete yard) it's a great place to see how your suspension is working.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too

Offline Past-my-Prime

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Re: Past-my-Prime Shock Thread
« Reply #6 on: July 20, 2019, 10:30:13 PM »
Thanks Laitch. You're right - best to let the initial post continue rather than side track the discussion.

Spring is better at least compressed (softest) setting when it's just me and no luggage. Shock damping doesn't seem any different as far as my butt can tell.

Did a bunch of other things today on the bike. Got a bit of a test ride after.



  • North Shore of Lake Superior
  • 1989 K75 RT

Offline alexg

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Re: Past-my-Prime Shock Thread
« Reply #7 on: July 21, 2019, 06:08:48 AM »
Hi:
Good thread; hope this does not qualify as highjacking!

Mine has harshness regardless of the spring setting. When I ride with my wife (another 120lbs) it seems to get better, but not really. I believe that in my case it is not softness of the damping but sort of a gap that is most noticeable in sharp road features. The bike has less that 15000 miles, but according to Johnny, that is 15000 miles too much. Is this what most of you experience?

Almost ready to buy a BSK.
  • Michigan
  • '93 K75S, 1975 BMW R75/6 & 1984 Yamaha RZ350
Alex G.

Offline Laitch

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Re: Past-my-Prime Shock Thread
« Reply #8 on: July 21, 2019, 08:03:25 AM »
. . . hope this does not qualify as highjacking!
 I believe that in my case it is not softness of the damping but sort of a gap that is most noticeable in sharp road features.  Is this what most of you experience?
As Chaos indicated in another thread, ride comfort is a personal experience.

I don't expect the suspension of my moto to be like the air ride suspension under a moving van hauling valuable grand pianos. What I want is control over rough roads and stability in turns. If a rear shock has both preload adjustment and rebound damping adjustment, I'm likely to get what I want. The more modes of refining those adjustments, the higher the likelihood. The OEM shock has a basic preload adjustment and that's it. I replaced mine when the moto would bounce and the shock would bottom out with a hard knock. That happened around 3000 miles into my ownership at 24K miles.

My current shock has five stages of rebound adjustment and ability to compress or extend the spring for preload by using screw adjusters. I have it set so all I need to do is rotate the rebound adjuster from 1 to 4 for two-up riding and we're good to go.
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline The Mighty Gryphon

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Re: Past-my-Prime Shock Thread
« Reply #9 on: July 21, 2019, 10:56:30 AM »
I'm pretty convinced that with their virtually unlimited resources, government will ultimately win the battle of ride quality. 

There is no way the designers of suspension components for our machines can keep up with the deterioration of roads under the control of our politicians.  It's probably best to just accept the harsh jolting of a ride over the crap highways where we ride, with the hope that we at least can achieve enough tire contact to control our bikes.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too

Offline Martin

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Re: Past-my-Prime Shock Thread
« Reply #10 on: July 21, 2019, 06:11:08 PM »
I've had mine for twenty one years. I replaced the first OEM shock in 2002 (All dates approx.), with a rebuilt and upgraded RAD shock. Replaced the RAD with another RAD in 2014. I've got no complaints with it's performance and I have ridden a couple of other Bricks with different shocks but I didn't play around with their settings. He charges $240.00 Au for a rebuilt re-chromed shock and turns them around in a week. He will change spring and valve rates if required, but so far I've stuck with his standard rebuild. If you want one in a hurry the local BM wreckers will sell you on a RAD for a bit more money. As I have now slowed down a bit and they worked fine even when I did a bit of scrapping I'll keep using them. But next time I get one I'll have a talk with him and see what he says. The last two times I couldn't wait a week so I went to the wreckers. By the way who made the OEM shock?
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Past-my-Prime

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Re: Past-my-Prime Shock Thread
« Reply #11 on: July 23, 2019, 10:03:37 PM »
OK so on setting #1 (softest setting for "solo") it is nicer / not so harsh on bumps . . . so more comfy.

However, it seems that it does a bit of a "rocking horse" feeling which might indicate lack of damping on rebound.

I never raced or did much "performance" riding so it's hard to know what is best.

My conclusion however, is with the 30 year old stock rear shock/spring assembly, the middle setting is best. So I'm back there. But maybe I need a new rear shock after all. Damn!

Looking at it, I think the rear is a very easy switch.

Unlike the front forks which look a bit like a dog's breakfast of little bits that either want to break, not come off at all, go sproinging across the garage, or get lost. I've experienced all of these in a single task.
  • North Shore of Lake Superior
  • 1989 K75 RT

Offline Scott

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Re: Past-my-Prime Shock Thread
« Reply #12 on: July 23, 2019, 10:26:30 PM »
My test for a shock(s) is how it performs on a fairly fast, long sweeper, if it doesn't dampen well, i feel a bit of an oscillation, an uneasy feeling.  My 4K mile stock shock, on #2 pre load is pretty  good in that scenario.  I'm about 160#.  BTW, front forks aren't too bad to r&r if you do a bit of due diligence before hand.  chunk..
  • SoCal
  • bmw R100r, bmw k75, hondapotamus G/W, XT 500 enduro

Offline Past-my-Prime

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Re: Past-my-Prime Shock Thread
« Reply #13 on: July 23, 2019, 10:39:36 PM »
I took some lovely long sweepers in the 160-165 km/h range and did not like it. I'll be resetting to position #2 and try again. Thanks for the advice.

Front forks don't bottom out, don't jiggle when on washboard-type turns, and except for when I had rear set too soft, were not giving me a rocking horse feeling on a straight-away but with the rear re-set, are better.

Before messing with things like front forks I need to check valves, lube spline (now that I got some Honda Moly 60) and see to that slippy clutch. I am happy with how the suspension is working now. Maybe the forks for a nice cool fall day.
  • North Shore of Lake Superior
  • 1989 K75 RT

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