Might need to adjust the 500 rear dampers - not sure what to do?

[McCabe-Thiele (Ted)]

Went out for a short ride today as the sun is out - nothing epic just 18 miles or so  to put a few extra miles on the 500 before winter sets in. I'm starting to really love the way it sounds & feels - so very different to the 400 in terms of flexibility through the gears.

When I rode it before the rebuild the front suspension was overly hard plus it made some horrible clonking noises under braking. On dismantling I found a PO of the front forks had fitted some spacers between the top of the springs and the internal top nut. I removed the makeshift spacers returning the set up to standard as the springs were still within the original limits in uncompressed length.

The ride is good on good road surfaces but there is something almost harsh about the way the bike rides over road repair strips at 40-50 mph. At the moment the rear damper spring setting is set on the lowest setting so presume that's softest (I'm 15st). Looking at the design I guess you need to rotate the adjuster with some sort of C spanner to harden the spring rate. I believe the rear shockers are standard ones.

What size tool do I need to rotate the rear damper spring to the second setting & will that improve anything or make it even worse?

[Bryanj]

Just a C spanner Ted

[Seabeowner]

If they are the original shocks then they may well have lost their damping. The shocks on my 550K3 seem to have absolutely no damping so you just bounce up and down. My 550F is not bad so it's a bit random.
Also the damper in the front forks is a sealed unit and I have found some are better than others. Presume there is a sealing ring that could wear particularly if it's been used with dirty oil. Later bikes have seal and parts that could be replaced separately.

[Johnny4428]

Old fashioned bicycle spanner works on the shocks too Ted! Think they were for the bicycle bottom bracket crank bearing caps.

[McCabe-Thiele (Ted)]

Old fashioned bicycle spanner works on the shocks too Ted! Think they were for the bicycle bottom bracket crank bearing caps.

My brother should have one of those bottom bracket tools - the dampers seemed quite good still as I dismantled them from the spring to clean them up - they only dampened in one direction iirc.

[taysidedragon]

Ted, the term "preload" on bike suspension is a bit of a misnomer. Increasing the preload doesn't "harden" the springs, it just lifts the bike up a set amount to put the suspension travel in a better position for the combined weight of bike and rider. That's why you increase preload when carrying a passenger.

The spring rate is set at manufacture. Different spring rates are available from specialists.

These old bikes have fairly simple suspension and damping systems, they're not as good as modern bikes at coping with bumps and potholes. A new pair of decent shocks is the only way to tell if your old ones are worn unless you got them tested by a specialist. That would probably cost as much as a new pair! 😲

[Murf]

As said I would expect original dampers to be pretty basic even when new and the years won’t have helped them. You should have compression and rebound damping but I can’t imagine there was ever a lot of compression damping. If you want a good ride then some new aftermarket units are the way to go. If you want originality then it’s a case of a poorer ride, we have this problem on the CBX Z twin shocks. I haven’t got to this point on my 550 rebuild but maybe some Hagon shocks can be disguised quite well to look like the originals. I’m sure someone on the site knows the best way to go.

For the front forks you can mess around with oil weight, I imagine ATF was specified as standard which is appropriately 5 to 10 weight  I think. With fork oil you can mix the weights to give a custom weight eg add some 15 to 10  to give 12 etc.  10 weight is a good starting point for the road.  All that said, with the crap roads we have even my modern bike can feel rough at times. Sad to say the roads were a lot better when the 500/550 first turned their wheels on them.

[McCabe-Thiele (Ted)]

Presumably if I adjust the rear dampers that will lift the rear wheel a tad. Certainly worth a try as there was a fair bit of shock absorber damping mostly one way only as usual with older damper designs. Iirc there was little resistance when pulling upwards but a fair bit when pressing back down. (might have been the opposite) I assume like most old designs they were not two way - if they were two way mine are goosed.

[Bryanj]

Wont lift the wheel Ted, just make the shokers harder to push down

[McCabe-Thiele (Ted)]

Wont lift the wheel Ted, just make the shokers harder to push down

So it's not like pre-loading at the front, I wondered if the spring tension would push the damper unit down so the swing arm was lower creating a slight increase in ride height. TBH the rear dampers seemed pretty good to me, I'll see if I get used to how it rides our local poor road surfaces.

At a glance it looks as if the exhaust will have to come off to get the bottom bolts out or is there a trick to make it simpler if I do replace them next year?

[taysidedragon]

Wont lift the wheel Ted, just make the shokers harder to push down

So it's not like pre-loading at the front, I wondered if the spring tension would push the damper unit down so the swing arm was lower creating a slight increase in ride height. TBH the rear dampers seemed pretty good to me, I'll see if I get used to how it rides our local poor road surfaces.

At a glance it looks as if the exhaust will have to come off to get the bottom bolts out or is there a trick to make it simpler if I do replace them next year?

If the bike is on the centre stand then , yes the swingarm will lower slightly.  When the wheel is on the ground the seat will therefore be raised slightly.
The shocks will not be harder to push down because the springs haven't changed.

[Bryanj]

The maximum length of the shock is fixed by the length of the damper rod Ted, it can only get shorter as wheel is pushed up then returned by the force of two springs.
As to swapping them remove rear bootrest bolts and you should get enough "wiggle room" to get bolts out