Chaps, need some advice again. My 5 year old, 22k miles, is in the workshop getting a new chain and sprockets. However, the mechanic tells me he thinks the rear monoshock is 'blown'. :( Says there is oil from it around the bottom. However, I clean my bike methodically, use WD40 all over the shock. How do I know if he's telling the truth or just after my cash? I did notice the ride was a bit bumpy, that's why I asked him to look. But I was just going to harden it up a bit (up to 6 or 7), but he says this will not help now?
you can probably get a used Katana 600 shock shipped for less than $40. It's a direct bolt-on, and anybody with opposing thumbs and a socket wrench can install it (no need to pay for the mechanic's time). Total time for the mod should be like 30 minutes, max.
Even if you're shock's still working, this mod is well worth the small price. If it's shot, no need to replace it with the same sloshy stock unit.
in the For Sale section:
http://www.gstwins.com/forum/viewtopic.php?t=16220
I'll second that. Makes a huge difference in ride. I got a kanatuna schock off ebay for $20. It wasn't too hard to install either.
Thanks folks. Buuuut, how do I know if I really need to replace the shock? I haven't really noticed the bike is THAT different - would it feel noticably different if it had gone? :dunno: The oil the mechanic is on about is probably that sprayed on by me to combat winter corrosion. I've yanked the pre-load up. I don't really want to buy a new one if I don't need to (the bike needs other things first)??
With the shock removed, to quote the Haynes manual..."Inspection 5 Inspect the shock absorber for obvious physical damage and the coil spring for looseness, cracks, or signs of fatigue. 6 Inspect the damper rod for signs of bending, pitting, and oil leakage. .... 8 If the shock absorber is damaged or worn it must be replaced. "
Well that is plain but it doesn't tell you how to test it does it? :dunno:
Let's try the Suzuki manual...."SHOCK ABSORBER Inspect the shock absorber body, bushing and bearing for damage and oil leakage. If any defects are found, replace the shock absorber with a new one."
Great! Another revenue generator for the dealer. :x The Clymer manual also echoes the two previously mentioned publications. So, what's a GS owner to do besides take the word of your mechanic?
Without building a shock test apparatus you basically are reduced to a visual inspection. Thoroughly clean the shock at the next opportunity, dry it off, wait a few minutes, then seat your self on the bike and proceed to bounce up and down on the seat until you are tired of doing so. Next inspect the shock for oil leakage. If it is puddling or near dripping, replace it.
It galls me to rely on such non-empirical methods, but it is only a spring and oil filled damper. Check your local breakers for a spare. Make certain you inspect it first! :roll:
Thank you. Now I don't want to split hairs here, BUT, if you can't tell from riding the bike whether the shock is knackered or not why would you bother replacing it? I have cleaned it up like you said, and I'm going to keep a close eye on it for leaks, fluid loss etc. But I kinda hoped someone would say, 'oh it will feel really different if your shock's gone'. If you can't tell, what's the point of the shock in the first place? :dunno:
If I just press on and it has gone, what's the worst than can happen?
Quote from: SpitfireThank you. Now I don't want to split hairs here, BUT, if you can't tell from riding the bike whether the shock is knackered or not why would you bother replacing it? I have cleaned it up like you said, and I'm going to keep a close eye on it for leaks, fluid loss etc. But I kinda hoped someone would say, 'oh it will feel really different if your shock's gone'. If you can't tell, what's the point of the shock in the first place? :dunno:
If I just press on and it has gone, what's the worst than can happen?
you would be able to notice it. the ride wouldn't be stiff.... it would be really bouncy
Good and valid points. Let us do some "what if" thinking.
With no oil in the shock there would be no gradual extension or compression of the device. Only the spring would be there to buffer your riding experience. Given a sufficient displacement, you would experience a bouncy ride immediately after the jolt that would eventually dampen to a null. The truth of the matter is that some dampening would occur because of the air in the piston cannot instantaneously escape from the same path as the oil. The oriface used by the escaping oil would be the limiting reagent in the mechanical oscillation (forgive the mixed metaphors please).
The speed you ride is a major variable in the equation. The suspension is there to assist you in maintaining control of the vehicle. If your speeds are sufficiently low, a little oscillation is insignificant. At 80 mph, oscillation could be serious. It means a loss of traction of the rear tire due to reduced friction from lack of tire contact. Without contact, the free-body diagram of the traction model will result in uncontrolled movement of the bike. My guess would be rear spin out while in a curve resulting in either a high side or low side depending on your lean angle. :o
If all the roads you travel are perfect surfaces, no suspension compensation would be necessary. Knowing that is not the case, it all depends on your comfort level and performance requirements. I know the M.O.T. requires the front dampers perform to a certain level (Haynes book reference - I am in the US), do they view the rear the same way?
In essence you may be able to ride, with your style and habits, forever with a leaking shock. You will adapt and compensate for the changes in the suspension. Once the shock variable changes to the point that you cannot compensate for it, you will be the first to know.
Cheers guys. :thumb: Just one last question on this....How likely is it that a 1999 22k GS rear shock is going to need changing? What's the average lifespan for these things, roughly?
a. Fluid (light oil) on the ground
b. REAL bouncy
c. You want a katana shock anyway... Just do it.
I got one for about $20 too, delivered to my door. The bike will sit a "tad" higher and it will make it actually lean a bit when on the sidestand. Won't bottom out with two people any more.
I replaced mine (on an '01) after 12,000 km, becaue I replaced the fork springs with Progressive Suspension ones and discovered just how awful the rear was.
Unless the shock blows out on you, which doesn't happen all that often, it will deteriorate slowly and your riding will adjust, so you may not notice how bad it is. But when you replace it with something better you will.
In answer to your original question, you should be able to see obvious damage to the piston and springs and if there is you should replace the shock. But obvious damage is not the whole story and it is possible for the shock to look fine but actually be dangerous.