Koni Rebuild + Springs

Discussion in 'Airheads' started by brocktoon, Oct 5, 2012.

  1. brocktoon

    brocktoon Been here awhile

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    My /5 came with a set of Koni 7610-1298 shocks. I've rebuilt them, but I'm left with a few questions:

    • When rebuilding these -- presumably after 40-odd years of use -- is it pretty much a foregone conclusion that the spring will need replacing?
    • If you do replace the spring do you need to go with Ikons, or are there other springs worth considering?
    • Anyone have a source for pin spanners that will access the top dial of the shock? It's incredibly narrow, and the same pin spanners that opened the body for me can't fit in the top
    • Anyone know of a good, reasonably priced spring compressor to fit Konis? I tried one from Harbor Freight one and it's too big to fit between the coils.
    #1
  2. Voltaire

    Voltaire Titanium and Ceramic Hipster

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    I rebuilt a set of Konis recently.
    I used the bathroom scales and the drill press to check spring rate....:rofl.......worked for me.checked off Ikon chart...
    Ikon also have the seal kits and springs.
    I used a Black and Decker workmate, with one end of the shock bolted thru and a bit of metal thru the spring held underneath with vise grips.....wear safety glasses
    Pin tool, I got a bit of flat 6 mm plate, hacked out the middle to get around the shaft, drilled two 4mm holes for the pins and used drill bits......thats how we roll in New Zealand.....:freakywe don't have a Harbour Freight......:cry
    I can post pics if anyone interested.
    filled up with 85 ml of Spectro 10 wght......

    According to our local Ohlins Distributer they are 70's old skool single action over sprung rubbish..:evil....mind you thats what some say about the ATE brakes as well. When I can get my R90 nipping at the heels of the 900ss and Norton Commandos I might be tempted to spring $1500 NZ on a set of Ohlins......in the mean time Ikon/Koni fit the bill.
    #2
  3. Boxer Metal

    Boxer Metal Mad Scientist

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    If the shocks compress and inch when on the bike in the middle setting and they don't bounce when you push down on the back of the bike then they are probably OK.
    #3
  4. gsd4me

    gsd4me 90% bluff

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    A mate of mine rebuilt a pair of Koni`s this morning, new seals and oil. Not including removal and re-fitting, it took him about 30 minutes for both. He used 80ml of 10 weight fork oil in each one, pretty much as Voltaire said. If the springs are progressive, it is easier to compress them if the tighter wound end is at the bottom.

    Anyone looking for well priced shocks, could have a look at these.
    http://www.gazisuspension.com/
    #4
  5. pommie john

    pommie john Long timer

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    Quite a few guys are using Gazi shocks for historic racing . They are meant to be pretty good.


    As for the Ohlins guy saying Konis are one-way damped 70s technology, well yes, but they are going on a 70s technology bike. And compared to the price of Ohlins dampers.....

    I don't understand why many modern bikes ( like my Ducati Monster) have shocks with a really soft spring and hard compression damping. If anyone can enlighten me I'd be grateful.

    I remember a story from Kenny Roberts autobiography when he was arguing with the suspension guys that they were using too much compression damping and not enough spring rate. He stripped the shock and found the compression damping valve, threw it in the bin and put a stronger spring on the shock and went out and rode it like that. He knows his stuff so there must be something to it.
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  6. gsd4me

    gsd4me 90% bluff

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    That`s good to know. My mechanic has a pair he bought on spec, but hasn`t used them yet. I`d have one on the R100GS he is building for me, but Gazi only make paired units, nothing for single shock bikes. We`ll be using a Bitubo initially, basically just because he has it; we will have to see how it goes.
    #6
  7. supershaft

    supershaft because I can

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    I never heard that story pj but that is the exact way I look at it too. Lindemann from Lindemann Engineering (the guy who invented high and low speed damping adjustment) was on the exact same page too. Among many others that I have read.

    40 year old springs? They can be like new. I have 30 year old springs that are like new. I am super touchy about my suspension setup but I don't replace things if they don't need it.

    Which brings me to shock rebuilds: What is it with all the recommended shock rebuilds? I just looked into a rebiuld kit for my Fox. It's nothing but rubber seals. But my shock isn't leaking oil or gas. Why should I rebuild it?? :ear What is the wear items in these shocks? Some say the oil but I don't see it or feel it. Do some shocks have bushings in the shock body/shaft? Mine doesn't. :ear They say your shock will change over the years but I don't think my Koni's or Fox ever has. In this same time frame I have worn out a pair of fork tubes and sliders and am about half way into another set but . . . .
    #7
  8. Voltaire

    Voltaire Titanium and Ceramic Hipster

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    Well as the Ohlins guy said to me " the best you have ridden is the best you will know"

    I'd like to try a set of Ohlins but they are a bit pricy for me.....and I don't like the colour....but apparently they come in black too.
    They are damped both ways so the springs can be lighter....but they do need to be set up for the rider and application,
    buying Ohlins off Ebay or a retailer and bolting them on will not give the desired results.

    Springs wear out, depends on how they have been used over the years.
    Which brings me to shock rebuilds.....if your shocks are ok leave them alone, the last 3 sets of Konis I have done the oil was well past it best by date...more like black splooge.
    Seals harden with age and whilst supershafts go on and on and on... normal shafts wear over time.:rofl
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  9. supershaft

    supershaft because I can

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    I have ridden tons of bikes with Ohlins before and after I got a Fox for my own bike. I got a fox because they hold up a lot better than Ohlin's for some reason(s) and work about as well. Ohlins? I think I would rather have Penske's.

    I have seen a few sacked springs but overall I think it is a myth.

    Shaft wear? My shocks don't have any. Like I said, I have seen my forks wear. I know what to look for.

    Oil? I suspect where/how they are stored effects it more than anything although I don't know for sure.

    I have seen tons of Ohlins with blown seals for some reason. Other shocks too. I'll replace them when they start leaking and not before. So far I have never had a shock leak other than stock ones.
    #9
  10. Prutser

    Prutser Long timer

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    Fork fluid wears because of dirt in the fork and from parts inside that wear.(and a lots of other reasons)
    A lot of the decline comes from moisture that gets in the oil.

    Its the same with shocks. Using a bike off road or on the race track can make the temp inside rise up to 90 degrees celsius or more. Someone in South Africa told me that in some modern WP ktm shocks there are plastic pistons inside that can even melt because of the heat when doing serious off roading.

    When a shock cools down moisture wil form inside and helps the decline of the oil.
    The metal particles coming of the moving piston inside will turn the oil in to polishing paste.
    That paste will wear all the parts in the shock. The lubrication will get worse and worse in time or miles.
    Particles with a size of 0.006mm can cause that a shim on the piston will not close. That way you could lose damping.
    Shock oil can smell like SHIT and look like it too.:huh

    So servicing shocks might help a lot.

    The so called "Quality brands" try to get as less friction in their shocks as possible.
    So they use seals that are not as tight as other brands.
    And that might cause them to leak a bit more often than some other brands.
    The same thing as Super Shaft mentioned about /5 fork seals in another thread. They can cause SO MUCH stiction which makes the fork feel firm......!
    The same can be said for shocks. Some brands choose for a long lasting tight seal that might have a bit more stiction. Others go for less stiction that could make the shock smoother but sometimes a bit more delicate.

    Every brand has his own philosophy about whats best. Thats why I think everybody has their own favorites
    And you have to choose what fits your bike and your demands best.(not to mention budget):evil

    I have seen a lot of bikes set up wrong with the most expensive shocks that were handling worse than some bikes with cheap shocks set up right.

    Just some of my experiences I would like to share....!
    (sorry for faulty English, its not my daily used language)
    #10
  11. gsd4me

    gsd4me 90% bluff

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    Read your post a couple of times and couldn`t find any evidence of faulty English. :thumb
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  12. Prutser

    Prutser Long timer

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    Thanks to google translate :lol3
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  13. supershaft

    supershaft because I can

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    Yea, I really enjoy your posts here Prutser!
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  14. Prutser

    Prutser Long timer

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    Thank you SS.
    It takes me ages to type a reply. :knary
    But I still enjoy it.
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  15. supershaft

    supershaft because I can

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    It takes me forever too and English is my first and just about only language.
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  16. Kai Ju

    Kai Ju Long timer

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    My native language is German and I'm used to the garbage that comes out of most translation programs. Well, I just tried Google Translate and I'll be damned, I could actually read it. Wow.

    Thanks for the tip.
    #16