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Thread: Gold Valve Emulator

  1. #16
    Registered User gertiektn's Avatar
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    When I was a kid and too poor to have a rifle cleaning rod... we used clean our rifles, and shot guns with a lengthy piece of twine and old piece of towel and pull it through... It worked and was easy to carry in the field. You can add a pull stick tied to the twine to add pulling power. We used a 3/4 X 3" piece tied to the twine.

  2. #17
    Quote Originally Posted by gertiektn View Post
    When I was a kid and too poor to have a rifle cleaning rod... we used clean our rifles, and shot guns with a lengthy piece of twine and old piece of towel and pull it through... It worked and was easy to carry in the field. You can add a pull stick tied to the twine to add pulling power. We used a 3/4 X 3" piece tied to the twine.
    Thanks, after doing each rod twice, washing them in the sink with soap and water proved very effective.
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  3. #18
    And now a ride report. It's taken a while as I experimented with changing the compression damping via the spring preload and the rebound via fork fluid. Ultimately, I ended up very close to RaceTech's suggested settings -- 2 turns of preload and 15w fork oil.

    I am very pleased with results. To be sure, the ride is sport bike firm but with more than adequate bump compliance. The bike feels much more stable and planted in turns. I would do this again (especially since it would be much easier the second time).
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  4. #19
    Registered User j_withers's Avatar
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    Hey Gang, I am trying to wrap my head around the 15W fork oil. It seems extremely heavy for a 1972 /5 BMW. Is it due to the Widened holes on the dampener rod?

    I put my forks together with the gold valve, added 15w, but haven't ridden the bike yet. The forks however feel extremely stiff. I'm going to take them apart today and make sure nothing is binding before i take it for a ride.

    -josh

  5. #20
    See my last post on the first page. If you're taking it apart again, might as well add some extra holes to the damping rod to make sure you have enough oil flow through there. You can't have too much as the Gold Valve will control the damping, but you do have to make sure you have completely defeated the stock damping circuit. And it will feel stiff in the garage, particularly if you put in the RaceTech springs. Just ride it and see how it feels.
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  6. #21
    Registered User j_withers's Avatar
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    I did all the drilling during assembly the first time. I don't think I need to do any more.

    Today I drained the 15W oil.
    I also realized that there was a serious gap (1.5 inches) between the Race Tech springs and upper fork cap. I increased the PVC spacers and used 5W fork oil and the forks rebound as expected and feel much less stiff. (Stiction is OK)

    I'm going to do my first ride tomorrow and who knows... I may end up using 7.5 or 10w oil.... but at least now i'm not afraid my arms will get punished from the stiffness.

    I'll report back...

  7. #22
    '92 R100GS brittrunyon's Avatar
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    Maybe I missed it in your post but:
    What bike are you working on?
    Did you put RTGV's in both tubes?
    Nice work. Thanks for sharing.
    1992 R100 GS

    Big Bend Ride video at http://brittrunyon.com/
    More riding videos @ http://vimeo.com/user2721333/videos

  8. #23
    Not sure which of us you are asking but I did it on my R90S and you do have to do it in both tubes.

    Quote Originally Posted by brittrunyon View Post
    Maybe I missed it in your post but:
    What bike are you working on?
    Did you put RTGV's in both tubes?
    Nice work. Thanks for sharing.
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  9. #24
    Registered User j_withers's Avatar
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    It is a 1972 R75/5

    Quote Originally Posted by j_withers View Post
    Hey Gang, I am trying to wrap my head around the 15W fork oil. It seems extremely heavy for a 1972 /5 BMW. Is it due to the Widened holes on the dampener rod?

  10. #25
    not lost til out of gas chasmrider's Avatar
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    morning all, J_withers didn't follow race tech's instructions, they call for a 15 mm preload on the fork springs, which is one of your adjustments for how stiff your forks are. race tech also says you can use anywhere from 5wt fork fluid to 30wt, although anything over 15wt is probably for racing. also they make 3 different springs for the GV, which can each be set from 0 to 7 turns. I just put GV's in my 1990 R 100 GSPD ( different forks than you guys ) and am thrilled with the results. I put a GV in both sides, after some mods, yellow spring, set to 2 turns, 10wt fluid, this is probably stiffer than you would want for the street, ( unless you like to go fast ) but I am thrilled with how my bike handles now.
    don't know where I'm going, but I'm making good time. 1978 R 100 S, 1990 R 100 GSPD, 1992 R100R, 2005 R 1200 GS

  11. #26
    Registered User j_withers's Avatar
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    Quote Originally Posted by 128521 View Post
    morning all, J_withers didn't follow race tech's instructions, they call for a 15 mm preload on the fork springs, which is one of your adjustments for how stiff your forks are.
    You are correct, I initially didn't have the 15mm preload. I do now though.
    Although, when i first put the forks together, the springs were at the top of the forks and I had to press them down to secure the upper fork nut. Perhaps it was how the bike was sitting.
    Upon second inspection when i realized everything was so stiff, the springs were far from the top (on centerstand) and i had to increase my PVC size for the correct preload.

  12. #27

    deburring damper rod inner wall

    Quote Originally Posted by ccolwell View Post
    I'm still wondering how to clean out the inside of the damping rod thoroughly to make sure I have all the debris from the drilling. I don't have a parts washer and just spraying carb cleaner and WD40 through the center is not gving me that warm, fuzzy feeling of confidence. Any suggestions?
    I used some small round files , reached in from outside to give the inside edge of the drilled holes just a bit of chamfer.

    This was pretty good but not gt, so I superglued (sparingly) a little flag of 320 grit SiC paper to the plain end of a loooooong 3/8 drill bit.
    As long as the paper didnt overlap itself, this Hone, Sweet Hone, fit down inside the rod just right.
    Wood dowel would work probably even better.
    Chucked the bit in a drill , dunked the business end in a bucket of water and gave it a few dozen twirls to deburr the inner walls.


    If/when the paper broke off, it wasnt too hard to remove from the bore- its just a through-pipe with a single restriction.

    There are bore brushes (gun / eng kits) that fit in there for the final scrub.

    Aside from getting the swarf out, its not exactly critical to perfectly deburr the rod ports inside; with all the extra holes, the velocity (and backpressure) of the oil cycling through will be much lower, so the potential to cavitate is much reduced.




    yeah I know this in ancient thread, but the internet is forever and this thread is worthy of pull back up top ! thanks colwell !

  13. #28
    Quote Originally Posted by j_withers View Post
    15W fork oil. It seems extremely heavy for a 1972 /5 BMW. -josh
    Reading through RT docs; seems that fork oil would ideally be more viscous than the 5 or 10 wt OE spec'd ,
    but an orfice-controlled damper rod system is subject to cavitation ( caused by back pressure, resistance to flow , oil piled up inside the rod/orifices so to speak) upon rebound motion.

    Higher oil WT is even more susceptible to this effect, so lower viscosity oil is the less-than-optimal answer.

    Simply enlarging the orifices in order to reduce the flow impediment will also reduce the dampening on compression stroke & lead to bottoming , lift-off, etc.

    With the larger rod holes allowed / required for the emulator, the higher WT will work better without the cavitation drawback

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