Reading Rick G's advice to someone else, I sent a Koni shock to RAD for a refurb. (Thanks, Rick.)

It came back with a Scraeder valve where there had been a threaded plug, the preload way tighter than it was when sent, and an adjusting wheel at the bottom of the shaft that I hadn't noticed before, though that was probably my blindness. Its never been on a bike in my ownership.





I know that suspension is a black art, but can someone advise me a starting point to work from for

• pressure in the top chamber
  
• preload (by distance from end of threaded part?)
  
• position of the adjustment at the bottom, which I presume is the rebound damping setting.
  

All advice is appreciated. The shock will be going on BOB the Blue Old Bike (ex RT), a stock K100RT, 1985. Used for local rides with little load, longer rides such as smithy's Northern Ride or my Snowy Ride with a few days worth of camping etc. gear. Pillion rare if ever.

Thanks in anticipation,

Bill

You will find some useful information on shock adjustment here.
Also the valve where the plug was is just the style of filler plug he uses, no need to top it up as he has filled it up already when reconditioned.

Hi Bill,

Whilst not a Koni shock - it looks/sounds pretty similar to the RAM shock adjustment. 

The pre-load is set by the big adjusting wheel on the thread portion at the bottom of the shock body.I suspect the shraeder valve may give you the damping setting (there is a knurled knob on the RAM shock for this which gives a choice of 13 settings, starting with it fully anticlockwise..mine are set to 5 clicks).


Can't comment on the "pressure in the top chamber" question - don't know how you would set this (or why you would need to). My guess is it will be equivalent to the combination of the pre-load and your load and will be what it is - greater the total load, the greater the pressure.

Hope the above set up guide may be of some use until a Koni user comes along...

The pressure in the top chamber is what it is, and is probably nitrogen at a very high pressure - not normally adjusted by and owner due to the pressures involved. 
The spring preload is set to maintain the correct ride height which is set by measuring sag with the rider seated. It would be adjusted when carrying a passenger of full panniers.
The adjuster at the bottom will be the rebound damping, this just adjusts to give you the stiffer (harder) feeling of the rear shock.

I've had a few of these shocks.

Do not touch the scrader valve, the shock rebuilder has charged the shock with nitrogen, theres no need for adjustment.

Preload; there is no standard setting, its dependant on the weight the bike carries.  I'd normally set it at 30% sag.  As a K100 has 110mm rear wheel travel, that would be 33mm.  Measure the height of the rear of the bike at full extension (I measure from the z frames to the ground) You may need some help to hold the bike at max height to get this measurement. When seated on the bike you want it to be sitting 33mm lower, adjust the spring collars to suit.

Damping: This is the adjuster at the bottom(for rebound damping only), this model Koni has 4 positions from lowest damping to highest damping. I generally start at the lowest setting move up one at a time and road test each setting. Again there is no standard setting, just the one that suits your needs.  When too high it will get firm as the suspension "packs down", that is the rebound damping is so high that the back suspension doesn't recover before you hit the next bump.

Al

I agree with Paul, start with minimum damping and increase it one step after a few days of riding.  I find that it takes time to adjust to and really feel what the suspension is doing.

Don't touch the Schrader valve!!!  The amount of nitrogen in it is spec'd by the manufacturer to provide a controlled amount of progressiveness to the spring rate and prevent cavitation of the damping fluid. 

Proper charging requires special equipment, you can't just throw an air chuck on it as you would a tire.  The volume of gas is very small, and the tiniest change will affect the shock operation substantially.

Point-Seven-five wrote:I agree with Paul, start with minimum damping and increase it one step after a few days of riding.  I find that it takes time to adjust to and really feel what the suspension is doing.

Don't touch the Schrader valve!!!  The amount of nitrogen in it is spec'd by the manufacturer to provide a controlled amount of progressiveness to the spring rate and prevent cavitation of the damping fluid. 

Proper charging requires special equipment, you can't just throw an air chuck on it as you would a tire.  The volume of gas is very small, and the tiniest change will affect the shock operation substantially.

Thanks to all for your advice, especially AL-58, Point-Seven-Five and BobT. I know some shocks on cars and motorbikes have a valve that the owner can use to vary the pressure, changing the ride characteristics, so I assumed this was similar. Good thing I haven't touched it apart from to confirm it is a Schraeder valve.  

I've been a bit busy, so haven't had a chance to install it on the bike yet, but now feel confident that with a helper for pre-load setting along with time and experimentation, I'll be able to have it nicely tuned before too long.

Great place, this forum.  

Bill

If you've sent it to RAD shockies then  you will not want to move the variable damper pictured in your post, if you do the whole damper valve is likely to loosen in the first 1000km as mine did twice. Having sent it to him. Mines sitting here in the shed from the second time I sent it to him with a rattle inside it that sounds like the dampers loose and I asked him to fix it as I didn't expect it to rattle 1000km after he serviced it. He sent mine back and same deal I reset the damper to three sweeps of the holes and again after nearly a 1000km it started to rattle.

I've come to believe the issue is he sets the damper solid not variable when he rebuilds and if I had left it alone I might still be using that damper.

A Koni Place in Sydney did refurbs, don't know if it still exists but one day oi'll fetch it off to a Koni Specialist and get it fixed, It was a bloody good shock before I sent it off to be refurbished.

Rad isn't known for failing on shockies but in this instance twice was enough for me.

if you changed the damper settings screw  ...you probably broke the seal and let pressure out ..

I agree leave it alone ...unless you have specific details as to how, why and strict instructions of what to do after you have done it .

he does a good job ...many assume that instructions in the user setup guide refer to all modifications and updates by the manufacturer since they were made ..

there could well be advice that many are not aware of nor sought .

some times experience is best delivered if you ask before playing.


good luck bill ...you may find a different rear end feel after installing a good shock .  made a huge difference to me.

btw I found that loaded sag at 25-30 mm worked well for me .

I just received a RAM SHOX today and will be giving my K1100 KONI the heave ho shortly.
Not that the KONI is bad but with my back the way it is I need a softer ride. It was when I put a RAM on my K100 some years ago I found out just how good they are in that regard.

K75cster wrote:A Koni Place in Sydney did refurbs, don't know if it still exists but one day oi'll fetch it off to a Koni Specialist and get it fixed, It was a bloody good shock before I sent it off to be refurbished.

That would have been Proven Products who were the Koni agent way back. They were in Guildford from memory.

Proven Products purchased the rights to Koni motorcycle shocks and built a factory in Albury.  They are now known as Ikon.

I've had Konis rebuilt by Chivos in Granville and by SOS in Penrith(a couple of times) and never had a problem with not being able to use the damping adjustment. That's what it's there for.

Al

Toperformance in Melbourne is where I bought my bike & car shocks from ( KONI )

http://www.toperformance.com.au/

try them

John Re

Melbourne Australia

AL-58 wrote:

K75cster wrote:A Koni Place in Sydney did refurbs, don't know if it still exists but one day oi'll fetch it off to a Koni Specialist and get it fixed, It was a bloody good shock before I sent it off to be refurbished.

That would have been Proven Products who were the Koni agent way back. They were in Guildford from memory.

Proven Products purchased the rights to Koni motorcycle shocks and built a factory in Albury.  They are now known as Ikon.

I've had Konis rebuilt by Chivos in Granville and by SOS in Penrith(a couple of times)




and never had a problem with not being able to use the damping adjustment. That's what it's there for.

Al

That is the difference then, you can use the damper, every time I moved it the shockie started rattleing after about 600 to 1000 kays, totally disappointed, so stowed it. Will put it back on when I get someone else to service it. Its a good shock.

A belated update re my Koni shock etc.

Proven Products were just down the road from me over 30 years ago when I lived in Guildford. I bought a set of height adjustable (by air pressure) rear Koni shocks for my Renault 12 from them. Good units. Had no need at the time to investigate motorcycle shocks. 

I had an Ikon on my red '85 RT when I bought it, but changed it for a RAM shorter one for the height, not because of any dissatisfaction with it. I've since seen a lot of disparaging comments about them on this forum, but it didn't give me any grief. 

The Koni has been brilliant since I installed it. A big improvement on the original one, which I think was a standard factory one but no idea of its age or mileage. It's currently on loan to wicky (Patrick) while his leaking one gets a refurb. The Koni's damping adjustment has been moved and experimented with, and has given no grief with rattles or anything so far.

Thanks again to the Krew from near and far who've provided such excellent advice and wisdom.  

Bill

If the damping adjuster moves then it means he's found a way to refurb the units without having it locked, that is good news. Nothing so disappointing as to have your finely tuned damper returned as a fixed unit and not be told of the deed.
Good luck with it. I hope it never fails you.