An Unholy Union II: Wp Extreme 50mm Conventionals on a G/S

Discussion in 'Airheads' started by Solo Lobo, Apr 9, 2011.

  1. ontic

    ontic

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    A little update,

    Got the bike back together, including reconnecting all my temporary (and unlabeled :baldy) electrics that had been pulled apart from all this front end wrangling.

    I put new stock bmw bearing cover/seals above and below the top and bottom bearings. The top one I had to cut right down to fit with my HPMGuy Scotts damper pin tower.
    All up I suppose I might have added 1-2mm of shimming...? and what do you know but I can now torque up the blind nut and it acts like it should- continuing to predictably tighten up the steering beyond 10-20 ft-lb :clap. The top of the stem is no longer hitting the bottom of the blind nut washer before the right preload is reached. I must say, I am fairly impressed with the exact tolerance that Rdubb designed these for- barely a mm of wiggle room but with stock bmw bearings and seals in their right places it will work- without the seals it won't.

    With my steel blind nut I played around with a lot of different torques on that top nut- to me it feels like the range is somewhere between 20-30 ft-lb. At 20 ft-lb I can't feel any wobble, but the bars fall away at the slightest tilt from center and they fall with no resistance whatsoever, and 30 ft-lb has a bit too much drag and doesn't fall very easily or quickly (though it still falls). Calibrated over two different torque wrenches (my clicker and my old deflection beam which both agreed), I've set mine at 25 ft-lb where it feels just right to me.
    If anything, I feel like I may have set mine a little loose (I plan on checking it frequently as the bearings settle in)- but maybe not, maybe I've set it a bit too tight.... however I can't see any way that 7.4 ft-lb would work.


    And wow, what a difference riding these forks shortened- cornering is a lot nicer. The bike feels nimble all over again but so so solid and planted in the front end. In contrast it was feeling a bit chopperesque with the full length forks, even slid up in the triples as far as I could.

    I played around with my fork clickers a little bit- both clickers all the way out, very nice and plush with an almost empty tank and no load on the bike- both clickers all the way in, nice and firm, thankfully a bit too firm so that it should be usable when the bike is loaded down more. Then I tried both clickers in the middle for a while (18 clicks out) and it seemed very nice.

    I need to get a slightly more road-friendly front tyre on as this ridiculous motorcross tyre howls at speed and feels like I'm riding on rubber marbles if I lean it over too far:eek1 Before then it will be hard to fine tune the forks for the road manners as far as oil weight goes, but for now this Penrite full synthetic ATF feels pretty nice.
    They list it as an equivalent to a 10W fork oil.

    anyone else got some updates:ear
  2. ontic

    ontic

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    Just thought I should add, when I got to this point on both forks the opposite end of the damper rod (the top) unscrewed rather than how it happened for Solo.
    Whatever end cracked first was going to go and I had no choice in the matter but at least it meant I didn't have to try to get that spring off.
  3. hardwaregrrl

    hardwaregrrl ignore list

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    I;ve got nothing new. Hit the whoops again and the front is still tight....so I think I may be out of the woods with that. Bought Race Tech suspension bible per AW suggestion and have been reading that. There is a good "test" section in the book that I'm going to try out. I checked my notes again and realized I used 20 ft/lbs on the blind nut. Worked like a charm. The machinist had mentioned something that I forgot to mention. When he cleaned up the threads for me he told me that the blind nut was designed to be pinched as it was being tightened into the stem. The threads look identical to me top and bottom on the blind nut, what did he mean by that? That would indicate that the stem threads would be tapered, but I don't see that????

    Hoping to do a few hundred miles off road this weekend, so should be good testing for the new bearings!!!!:clap
  4. ontic

    ontic

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    Since AW recommended that book, I've almost bought it a couple of times now. I'm not quite as efficient on amazon as I am on ebay:D One day I'll get it right.

    And yeah, at least we are in the same ball park, 20ft-lb felt solid but on the lighter end of the scale for me. It is something I am going to keep checking until I feel like I get it right- I'd rather not run them too loose again so if 25 is good I'll inch it down a bit next time and see what I can get away with.
    And here is one of the advantages of having a top nut that sets the bearing preload- we can actually easily use torque wrenches on them unlike the under clamp crown nuts- once I figure out the torque that works best it should be a cinch to set without mucking around with fall away of the bars (always a little difficult with cables and stuff confusing it)

    I don't know what your machinist meant about pinching the blind nut. There is nothing unusual about those threads that I can tell, I've screwed a steel swing arm thing all the way to the bottom of the threads and even turned with fingers it rides smoothly and easily the whole way. Luckily all my heavy torquing hasn't damaged my threads!
    John's point about the one-piece blind nut-washer possibly being pinched by the triple clamp was interesting (getting pinched on the washer where it sits in the depression of the stem pinch section- it would be a neat idea, however although it is very close, there is a 1-2mm of clearance around the washer so it doesn't actually get pinched.

    If it is a concern that 20-30 ft-lb is not enough to reliably hold that blind nut in place over time (is that the concern?) maybe once the bearings are preloaded, then the stem gets pinched and then the blind nut gets torqued up a bit more just to hold it in place? I don't know.:lol3
  5. redboots

    redboots Johnny Lung

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    Does he not mean the top triple, center pinchbolt? Thats the only thing that will stop the nut undoing. I doubt that 20ft/lbs will hold it for long without.... imho...[​IMG]

    Cheers,
    John
  6. hardwaregrrl

    hardwaregrrl ignore list

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    I dunno.....here I go again listening to people talk out their ass:deal. I'm not gonna try analyzing it anymore. I'm gonna run what I brung and keep an eye on the bearings. My bars will flop with a little push and they don't bounce of the steering stops. So I'm happy. All I have to do now is ride the shit out Of this thing!!!!!:1drink
  7. pennswoodsed

    pennswoodsed lizards,bugs and me

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    .001 was what I was taught/learned in the dark ages.
    Maybe different now,maybe wrong in my head but what I use if not specified by equipment manufacturer.
    Regards,Ed
  8. Solo Lobo

    Solo Lobo airhead or nothing

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    You are right Ed... my math is lacking! :lol3
  9. hardwaregrrl

    hardwaregrrl ignore list

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    So. Loose bearings again. Had a fun run up walking stick rd Friday afternoon. Bout a10 mile rode crossing from Georgia into n Carolina, rutted rocky washed out kind of stuff. By the end my bearings were loose. Got to camp and tightened them as much as we could with a pair of channel locks. Next day we rode hurricane creek in n Carolina on the Tennessee border. Really fun road with 4 or 5 river crossings. Each one deeper. Very rocky and rutted road, or pig trail as they call it. By the time I reached a mile in the bearings were loose again. Bike did fine but I couldn't feel the forks past concentrating on the loose bearings. Shot some good video which I'm having a hard time loading up. All in all I'm disappointed in the design of the stem. I ride the bike hard and it seems the stem isn't up to that. Is anybody riding their bike with these clamps off road? I really want to hear about your experience with the head bearings. I used a 24" braker bar last nite to tighten the blind nut. I cannot go too much more.
  10. Solo Lobo

    Solo Lobo airhead or nothing

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    Jenna

    With the upper triple clamp tightened on the fork legs, I wonder how the bearings are getting loose? That seems weird.

    I rode my bike in today, and the adjusted bearing's are much better (on-road).

    I am sure that the 10 and 15w oil is too heavy and still have some ways to go in turing the comp and rebound... thinking the smart money is in having the valving adjusted by a pro.

    Has anyone searched the KTM thread for head bearing issues? I did briefly and found nothing...


    Ontic,

    Any update from Marcus?
  11. hardwaregrrl

    hardwaregrrl ignore list

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    funny thing is I could never tell on road that my bearings were loose??! I rode home in the poring down rain with 606s on about 200 miles a lot of it very twisty and never once felt them.

    Found out I'm running 5wt racetech ultra slick oil. It's weird how thick the stuff is.

    Don't think the fork legs being attached has any bearing on it. No pun. I firmly believe the stem was not turned down enough and you really have to crank on the nut to get the bearings to slide on the stem and seat in the races. I think it's a poor design for our bike and will not stand up to the test of time. But that's just an opinion but after tightening them 3xs since renewed I'm feeling underwhelmed by the stoutness of the design. I'm no pussy......

    Loding this up 3 flights of stairs alone and toting carpet out on the return trip.
    [​IMG]
  12. Solo Lobo

    Solo Lobo airhead or nothing

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    Thanks Jenna,

    To re-phrase it... if you are getting the bearings correctly loaded, and then tighten the four bolts that hold the upper triple to the fork legs and then tighten the two bolts holding the upper triple to the stem I don't see how you are getting the top triple to move up the fork legs and up the stem to get looser?

    See what I mean? I would also not think the top triple can flex at all....

    So I wonder where the looseness is coing from?
  13. hardwaregrrl

    hardwaregrrl ignore list

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    Ok, I guess I'm not getting my point across. The fork legs being attached to the top clamp has nothing to do with the loosening of the bearings. The forks are attached to the triple, and the triple is attached to the stem. The stem with the bearings and races are what is attached to the bike. All of the play is the stem in the head moving fore and aft, the fork legs being attached to the clamps are only adding to the fact that there is the loosening at the head. The blind nut pushes down the top clamp sliding it over the fork tubes and at the same time pulling up the bottom clamp and seating the bottom bearing in the race.......but if the stem is too large for the bearing to slide over, your bearing will never sit properly in the race which will leave space. I tighten the blind nut with the top pinch bolts being loose, then I tighten the stem pinch bolts to 15ftlb and then the top clamps at 20ftlb. I really think the blind nut is not up to the challenge of pressing the the top clamp down enough to seat the bearing in the race. I checked the races last time thinking they were not put in far enough, nope, they were fine.
  14. Airhead Wrangler

    Airhead Wrangler Long timer

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    Hmmmm. I never did like this design, so I might design a new stem for this. Machinist time down here is about $10/hr and some of the guys I've worked with are damn good. I might sketch something up and have it turned. I'll let you know if I come up with something.
  15. hardwaregrrl

    hardwaregrrl ignore list

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    Thanks Spencer....I'm interested.:ear
  16. pennswoodsed

    pennswoodsed lizards,bugs and me

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    Hi,
    Been following this thread as my quest is similar ,using wp50s on my sv650 conversion . Having seen the complexity of the valving I doubt that my wp50s are are better choice than the showa 49s I bought first . I also have 43mm usd wps and 91 honda cr500 forks. Any input appreciated , I intend to use racetech gold valve and .65 springs in whichever set is chosen. Spring choice and ease of adaptability seem to recommend one of the Japanese sets.
    Thanks,Ed
  17. Beater

    Beater The Bavarian Butcher

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    PS - I'd be interested too if the price were reasonable ... You know $200ish ... maybe a little more.

    Just a thought .. . I have a '91 GS that I am underwhelmed with the forks ... especially off road.
  18. Solo Lobo

    Solo Lobo airhead or nothing

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    AW looking at just making a new stem... not triples (I am guessing)
  19. Airhead Wrangler

    Airhead Wrangler Long timer

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    Correct...

    ...and it'd be well under $200, well under $100, and maybe even under $50. I'd like to go with a toughened stainless alloy and maybe even cut the steering stop hole in it. We'll see. Good metal is tough to come by down here, but I've got a few ideas of where to look and I already know some really good machinists with CNC lathes that could spit these out rapid fire.

    It'd be something like this with a thin nut to gently preload the bearing and then a bigger cap nut on an outside thread to mash the top triple down on it to lock it in place

    [​IMG]
  20. hardwaregrrl

    hardwaregrrl ignore list

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    Fred, don't forget I have a set of KTM triples that will fit the WP5060 forks. You could get a stem from AW and just press the old one out and put the new one in.

    I'm worried that the forks will have to sit lower in the top clamp to allow for room to access the lock nut. Like so...

    [​IMG]