Bouncy Bike

I don't understand suspension very well. My bike seems bouncy while riding. Like little bumps seem to make it bounce. My fork oil is new and measured to factory spec. My rear is set to 3 and are the original. I'm 6'1" 185#. Should I raise the rear to 5? My front wheel and fork have zero play. But for all I know this little bouncing is normal and should be ignored. Big bumps seem to handled well. It's all the little ones that make it seem odd.

 

Sounds to me like your shocks, which weren't all that great to begin with, are all done. The original shocks on these bikes had a lifespan of 6000~8000 miles MAX, at 20K you need new ones for sure.

Pop one off, remove the spring, and see if it has any damping left. I'm betting not.

 

So you feel the front are fine then. Now how would I tell dampening?

 

Fronts are fine as long as the oil is fresh, at the proper level and the seals aren't leaking. (New fork springs would certainly improve things but that's another discussion.)

As for dampening, I just told you how.

-Remove a rear shock (only one.)
-Compress the spring slightly, remove the retaining collars and the upper spring seat and remove the spring.
-OPERATE the shock by hand; move the plunger in and out. It should have resistance to being moved; it shouldn't just slide in and out freely. I'm betting it slides in and out with little or no resistance (damping action.)

I can guarantee you that if you have the original KYB's that came on the bike and they have 20K on them that they will need to be replaced. The shocks that were on my '83 were all done, and I got that bike with 7100 miles on it.

 

Ok pulled it off and found it is original. Couldn't compress spring but im totally sure you are right on there status. What do I look for in replacements? I know they are 12.5 in length.

 

If fitz says their done their done. He knows his stuff.

 

I don't think it is a sure thing that these shocks are "done" by 7K.

My bike has 13.5K and the original shocks. The damping works just fine. I won't give any warranties to that statement, but I will say that it is much better to run what you got until they simply do not work anymore. If you set the dampening on 4 and it is the same as if it is on 1...then replace them.

At 20K, it would be fair to say they are done. Or it is at least likely they are done.

 

You did not read what Fitz wrote correctly. He said to take the spring off, then you compress the plunger on the shock itself. You don't try and compress the spring. Anyway, Len at XJ4Ever will have the replacements you will need.

 

I wasn't referring to the adjustable-damping units that your bike has; I was referring to the original simple spring-preload adjustment only KYBs that came on the 550s, 650s and other "base" Yammies of the day. (I had a '78 and an '80 SR500 back then too.) Those shocks were toast by around 6000~8000 miles; and weren't all that great to begin with. I've got a set in the junk box with 7100 miles on them and ZERO damping left.

I would highly recommend Progressive Suspension as a cost-effective, quality replacement option. I've got their 12-Series on both of my 550s and they're great.

 

Sorry for clouding the information then. Adjustable damping is a godsend in my opinion. Pull over and firm it up for the twisties. Once done...loosen it up for the ride home.

 

Man Chacal is going to love me this winter.

 

If it is "bouncy" now, you should replace the rear shocks/springs now. The springs hold up the weight (and you might want to go to a heavier than stock spring rate); the shocks dampen the spring oscillations when the wheel goes over a bump (clearly your present problem - might be in 1 shock, might be both; replace both for good measure).

At a minimum you should replace the shocks with known good ones (probably from this forum's classified section so that you can get a good idea about the seller) as an interim measure now before sinking in $$ to get a better, new set.

 

They work well enough for now. But I'll install new over the winter.