Koni Shocks restoration

[LWC82PE]

I have decided I definitely want to restore these Koni remote reservoir shocks and don’t want to leave them to waste away any longer. I had no success sourcing a manual of any sort from here http://ozvmx.com/community/index.php?topic=924.0 or Proven Products and they said there wasn’t ever a manual, but I don’t want to let that stop me.

I reckon some sort of Owners manual must have been boxed with the units when sold so if any one has one I would very much like to get a copy or buy it. I’m also interested in seeing any magazine article/test/advertisement/brochure on these shocks and a colour photo or picture of the shocks or the box they came in would also be good.

I reckon these are pretty rare units, and worth doing up as they are a piece of vintage dirt bike history and I don’t see many bikes with them or hear of other people who have them. If you have got a pair of these shocks or have restored a pair then now is the time to speak up!
The shafts look pretty good which is a bonus and the main issue with mine is that they are just leaking and in serious need of re-painting. Proven Products say no parts are available but I will still ask them again. My main concern is to get them rebuilt and re-gassed so they don’t leak. I at least hope I can get seals from a universal seal place if I cant get special shock type seals and wipers. If things like Teflon bands and o-rings are needed I am confident I can source/make these my self.  They still feel quite good in side and operate smoothly. I’m pretty sure I will not need new pistons or bearings but if it’s not too much of a hassle I will still get new bearings made or get them re-bushed depending on the type. But as I said before I reckon I could get away with just new seals/wipers, oil and gas on these shocks.

One thing at the moment  I would like to know is the set up procedure such as the position the floating piston has to be set to and the oil filling/oil level. I’m familiar with the Ohlins so I’m guessing Konis would be similar but no necessarily the same. I can already see one issue making it difficult if I was to just follow the Ohlins process. The Koni hoses appear to be semi permanently attached to the reservoir cap. The cap would be removable with the hose attached but there is no way I can see how you can assemble it with out loosing oil and trapping air. Anyone with Ohlins will be familiar with the process of filling the hose and reservoir with oil and then quickly screwing the reservoir onto the hose. It wouldn’t be as straight forward with the Konis. I may end up removing the hoses and putting threaded in re-placeable hoses that are able to be unscrewed at the shock and reservoir.
I’ve taken a measurement of the shafts and I was surprised to see they measure around 10.70-10.80mm. They are not 10, 11 or 12mm. so getting seals that size could be my big stumbling block. Since they are Dutch I assume they should be metric?

First thing I need to know is that on the non hose end of the reservoir the cap is welded on and in the cap is a small allen head screw. If I remove this screw will gas just come shooting out? I don’t think it would but want to check first. I assume under the allen head screw there is some sort of sealed needle injection filling valve correct? If this is serviceable I will probably leave it alone but if it’s leaking I will drill it out and put a thread in to take a standard Schrader type gas fill valve. If that’s not possible then I will weld in a fitting to take a Schrader valve. So I will be needing to know what PSI I need to charge these with nitrogen.

Once I know what will happen if I unscrew the allen head screw in the reservoir I can at least take them apart to get iside to see exactly what the seals are and hopefully see a number on them.

So that’s where I’m at now. I’ve matched up the original orange/red paint and already have one sticker for the reservoirs but that was the easy part!!

[Nathan S]

Setting the floating piston height is very much like setting the oil level in a pair of forks - so it's hard to say that it should be at exactly Xmm (even if I thought that I knew).
If the shocks weren't leaky, then releasing the gas pressure first will put the floating piston in the right spot for reassembly.

On the few remote cannister shocks that I've rebuilt, I've set the floating piston height, filled the cannister and hose with oil, and then screwed the shock body onto the hose. Then partially filled the shock body with oil and tapped the air bubbles out. Sounds like an easier, more reliable option than simply trying to work really really quickly. Or is there something in the Ohlins design that makes this difficult?
Not that this will help you with the Konis, by the sound of it. I've got the same problem with my KDX200 shock.

I don't know this, but I'll be amazed if the allen headed bolt releases the gas pressure. I'll bet that it will be a Ohlins/Yamaha style rubber stopper that you need to tap with a syringe.
If it's leaky and non-servicable, then I'd look at fitting the M5x0.8 allen headed bolts/syringe valves from SOS Suspension - much less obtrusive than schrader valves.

Edit: Fat fingers last night. The thread is M5x0.8 - sorry if I confused anyone.

[LWC82PE]

thanks for the ideas Nathan. i will remove the allen head screws tomorrow and see what happens.
the shocks have been leaking oil and have been compressed with low oil so the piston would be out of place i suspect so i really want to find out the correct position this has to be in. i will try and post some photos on here and you will see that because of the way the canisters are assembled and how the hoses are kind of permanatley fixed its not going to be that easy to do unless i make removeable hoses that have threaded ends, but i keep thinking the factory managed to do it some how this way.

[Nathan S]

Been thinking more about getting oil into the semi-sealed cannister.

For my KDX, I'm figuring that I've got a few options:
1. Simply fill the cannister before fitting the hose (Its hose is removable, but I still can't get into the cannister, unlike a Yamaha shock). This will make life hell in terms of bleeding the cannister/hose though.
2.  Work out some way of pushing oil under (low) pressure into the cannister. The floating piston height can be set/limited through the gas filler valve hole.
3. Fit a Yamaha cannister. I assume that this will cost me a custom hose, but then I'll have a fully, easily serviceable cannister and the problem is solved forever.

Maybe you could drill and tap a hole into the end of the cannister (next to the hose), and use it as a fill point. Or is that going to be too ugly?

[LWC82PE]

Today I went to undo the allen head screw on the end of the reservoir and I was surprised as it released the gas. It wasn’t very high pressure, maybe about 20 or 30psi, certainly a huge gush of 180 or 200 psi of gas did not come out. All this allen screw appears to be is a bleed screw. It has a tiny hole up the center and another hole drilled across the screw right through the center of the vertical hole. Its basically exactly the same as float bowl drain screw. Under the screw was a metal washer with rubber seal in the middle. The allen screw is about 4mm OD and not 5. Any way this is now the least of my worries.

I got the damper unit and reservoir apart with no major problems, the condition inside both was very good. Now the real problems begin. Really all these shocks need is new seals and wipers. The shafts are a odd size. They measure 10.72 - 10.75mm or 0.4220 – 0.4232”. the seal has an OD of about 19.80-20mm and the height is around 3.5mm. I’m sure its going to be very difficult to get seals.
I got a email from Proven Products (Ikon) today and they said they have no parts left and they bought all the remaining stock of parts for these shocks (23X series) a long time ago so I would be wasting my time contacting Koni in Holland.

I was also told ‘Koni have a reputation for using odd sizes which is why you will have a hard time finding any parts and why nearly 30 years after we don’t have any left. As for anyone else having any parts I strongly doubt it’

So it doesn’t sound too good so far but I don’t want to give up yet.

Any body know any old dealers who may have nos Koni parts?

Also Nathan have you got the phone number for SOS suspension? I couldn’t find their website

[Lozza]

Sean will have seals in stock IIRC about $20 ea.His number is 4732 5533 or 0412 245 176 Unit 7 9-11 Abel St Penrith South 2750

[LWC82PE]

i had an intersting chat with Sean at SOS suspension today. He does not have seals but there is a soloution if i want to pay a lot more money than i had planned on spending on these shocks. He said they are definitley worth restoring and they are a very good shock and they are about as good as the Ohlins of that period or not very far behind them.

[Husabergpete]

I have a pair of Koni 23x as well. They are currently with a local suspension expert who has told me he can do them. After reading your experience I'm not so sure. You can give me a call on 0401692800 and I'll let you know how I get on.

Pete

[Husabergpete]

I have been in touch with Mohamed Osaman from Dalmans Australia (T/A the Shockabsorber Reconditioners) Slacks Creek Qld.     email was     [email protected]   

Ph - 3808 2455

He said was was quite sure they could rebuild them.

Regards

Pete

[Colin Jay]

This probbably will not be much help, but back in the early 80's I attended a Honda service traning school where we we taught how to overhaul the Pro Link shocks.  Too prevent air being trapped inside the shock, we were taught to assembly the complete shock, up to the point of installing the reseviour rubber bladder, in an oil bath. once the bladder was in the reseviour the final assembly of the reseviour was done on the bench.

I rebuilt numerous shocks using this procedure before leaving the bike repair game, however it would not be economical for doing one off rebuilds as the cost of the oil (I used to buy it in 20L drums) would be prohibitive.

I will be keeping an eye on how you get on, as I have a pair of the same shocks that I used to have on my 1978 Bultaco 370 Frontera Mk11, that I am thinking of using on one of my XT500 Yamahas.

CJ

[YSS]

Gee , that must have been before the vaccum bleeder.

[LWC82PE]

thanks guys. i havent decided exactly what i will do as there are a few options. ive just been busy cleaning up various parts of the shocks. i got the reservoirs in good shape almost ready for paint now.

ive been trying to measure up all the various o-rings/piston rings in the shocks to source new ones and perhaps make up my own re-build kit for these shocks. i want to do it right and source the correct size o-rings and not just think 'oh that one looks close enough, that will do' but im having a hard time trying to determine sizes. ive dowloaded heaps of o-ring catalogues off the net but it only confused me even more. one source ( Geoff at Proven Products,IKON) tells me these Konis are designed in metric which is what i would of thought but he also wasnt 100% sure of that. everything so far tells me they are imperial though, but some parts seem in metric.

does any one know what system of metric that the dutch used back in late 70's/early 80's? there are several different standards of metric o-rings. i can find swedish and german and japanses and italian but cant find what the dutch used or maybe they used imperial? like i said before i was told Koni had a reputation for using odd sizes so it might not be straight forward. im thinking about buying an o-ring sizing cone but i can only find imperial ones.

i bought another set of these shocks for some spare the other week but they havent come yet.

will give an update on the seal/shaft situation a bit later on.