exhaust system

Discussion in 'Airheads' started by darmahman, Mar 4, 2013.

  1. darmahman

    darmahman "Illogically Deluded"

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    In the past I have put several sets of Staintune's on my BMW's. (airheads)
    Staintune no longer manufactures exhausts for the /7. The fit and finish was always perfect with them. I am interested in specifically the differences in quality and fit and finish to the Keihan's. I AM ONLY INTERESTED IN THAT COMPARISON. If you have knowledge of the differences or your experience with Keihan's I would like to hear your experiences but only with that brand. Thanks on the front side.
    #1
  2. Airhead Wrangler

    Airhead Wrangler Long timer

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    What I've seen of the Keihan stuff has varied quite a bit. Sometimes they just don't fit up very cleanly, sometimes they do. The finish quality on all of it has been a step down from staintune stuff I've seen. The welds typically aren't the neatest.
    #2
  3. Solo Lobo

    Solo Lobo airhead or nothing

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    I have Keihan headers and collector on my R80G/S, and it was a bit of a fight to install everything.
    #3
  4. Max Headroom

    Max Headroom lost in the '70s

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    I have bought two sets of Keihan silencers to date. The first set was their standard issue, intended as a direct replacement for /6 models and later. They are well made, nicely finished and are as quiet as the factory items. Having traveled only 15,000mi so far, they have years of life left in them and are currently on the shelf, awaiting their next assignment which is under construction. They were originally fitted to my R90S.

    The second set arrived just under two years ago, purchased direct from Keihan. They are the "Jim Cray" sport silencers, developed by Jim with the aid of an R100/7 and a dyno. Probably similar to the Staintune Sport silencers in design and noise levels. It took quite a few miles to get used to the new sound, and initially I had reservations, but they have grown on me and I now like the deeper, more authoritative "voice" the R90S now has.

    I'm happy with the quality of both sets, and won't hesitate to purchase another set of Keihan silencers for the /5 toaster I'll be re-assembling next year. My only observation is that they are prone to discolour, as many S/S exhaust systems are inclined to do. (Incidentally I also have a S/S header set of unknown origin or manufacture which don't discolour noticeably, which I find quite appealing. There are no markings or identification on them though, unfortunately.)

    Everything fits together as it should, and at a glance, from a distance, the Keihans look just like stock. They come with a 10 year manufacturer's warranty, but you probably knew that.

    No connection, YMMV etc
    #4
  5. boxerboy81

    boxerboy81 Stay Horizontal

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    I have Staintunes on now and a set of the Jim Cray designed Keihans in the shed. There was a LEO blitz on noise so I took 'em off for a while.

    In the past, I've also had a set of the stock Keihans.

    Fit was never a problem. Finish is good but Staintune is better.

    The seam along the bottom of the Keihans is finished differently, hard to describe, but Staintune looks better there. Keihans do seem to discolour more, around the area before the weld in the region of the bracket. It polishes out easily enough.

    Both sets of Keihans developed a small crack in the area where the bracket is. It doesn't seem to affect tune at all, but is a disappointment. They're half the price of the Staintunes, or were. I'd buy 'em again.


    [​IMG]

    https://www.youtube.com/watch?v=pYGmE05H7SA

    https://www.youtube.com/watch?v=xeQv-fO0-vY
    #5
  6. supershaft

    supershaft because I can

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    I am not claiming a cure all but keeping your front muffler clamps tight really cuts down on cracking there. I check all airheads I work on. It's easy. Reach down and grab the end of the muffler on twist on it. If you can twist it at all, the front clamp needs tightening. I find them loose ALL the time! A loose front clamp lets them vibrate a LOT compared to a tight one.
    #6
  7. chasbmw

    chasbmw Long timer

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    Steve,

    Worth trying the Keihans 10yr Gtee? But you are a long way away. Also check that the little cross bracket on your pillion/exhaust mount is not cracked, they often are and can cause exhaust cracking.

    I agree with Max on the Keihans, they seem to last forever and the ones I have fitted have all be sized properly.

    The sports mufflers were built because of the Internet, Jim had been talking for a couple of years about getting some sports silencers made to his own design, I was on the Motobins forum at the time and put the word out so between forum members and Jim's own customers, we got the minimum number of orders together so that he could get them made. They look stock apart from the outlet that is of a larger diameter.

    [​IMG]
    #7
  8. supershaft

    supershaft because I can

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    Those are very different from Staintune Sport mufflers. The Cray Keihans are a lot louder and freer flowing I know just from looking. Typically speaking, the perforated linings breath best but they are LOUD. They also tend to work best when tightly packed and the packing doesn't last forever.
    #8
  9. outfit

    outfit Been here awhile

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    #9
  10. Lornce

    Lornce Lost In Place

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    Had a complete set of Keihan exhaust with /5 type silencers on an R75/5. They looked good and sounded nice and civilised. But they had what appeared to be a smaller opening than a stock /5 muffler would have at the rear. Not a big deal on an R75, but when it became an R100/5 I'm almost certain they were choking up the motor.
    #10
  11. chasbmw

    chasbmw Long timer

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    #11
  12. boxerboy81

    boxerboy81 Stay Horizontal

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    The first set with the crack came to me like that. Warranty claim would be fraudulent, but it's really the distance!
    The JC's have only ever been on my bike, and the bracket is intact and the front clamps are always tight. I found the JC's popped a bit on the overrun, so ensuring the system was tight was part of the strategy to reduce that.


    The Jim Cray noise!:wink: I like them.

    https://www.youtube.com/watch?v=vTqO1hABIzw
    #12
  13. darmahman

    darmahman "Illogically Deluded"

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    That works for me. Does anybody have a set of the Keihan Jim Cray's they want to unload?
    #13
  14. chasbmw

    chasbmw Long timer

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    If you can't find any second hand, give Jim a ring on +441795538282, Keihans might have some in stock, but I'm told than produce these in batches.
    #14
  15. darmahman

    darmahman "Illogically Deluded"

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    just ordered a new set from Keihan...

    #15
  16. boxerboy81

    boxerboy81 Stay Horizontal

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    So, the natural progression of this discussion leads us to chatting about increasing main jet size and adding a K&N air filter. Do you know what you've started? JC suggest a 170 mj and the filter change.:evil

    http://www.bmbikes.org.uk/Forum/viewtopic.php?f=15&t=10793
    #16
  17. darmahman

    darmahman "Illogically Deluded"

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    Being at 5000 feet and most of my riding is in the mountains at 6000-7500 ft. I will probably wait and see, eh?
    #17
  18. supershaft

    supershaft because I can

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    Free flowing exhaust? Leaner mains is very often what they actually need. That and richer needle jets.
    #18
  19. Ron Bernert

    Ron Bernert hiding in plain sight

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    Curious, but how much shipped to the US? Thanks..
    #19
  20. darmahman

    darmahman "Illogically Deluded"

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    Hello Mr Mosiman

    Thanks for the email, prices as follows:

    1 Pair 38mm “Jim Cray” Silencers £272.76
    1 Set 38mm Twin Balance Exhaust Pipes £193.20
    1 Pair Silencer Mounting Brackets £ 13.26
    2 Off Silencer Clamps £ 12.30
    Freight to USA £ 85.00

    All items in stock at the moment

    Best Regards
    Beryl Chodynicki

    fyi - $861 US dollars











    #20