Airhead "Tips and Tricks"

Discussion in 'Airheads' started by elmoreman, Sep 26, 2006.

  1. hotwheels22

    hotwheels22 motorradRP + Airheads International

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    duh. fixed. sorry, multiple plates spinning here...

    didn’t think about the twisting but i may have felt it a tad now that you mention it.

    or actually the choke and enrichener cables may need to be thought out better next time i do this since they seem to have crosses over each other.

    but still this was way easier than doing all this after attaching the carb...
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  2. mark1305

    mark1305 Old Enough To Know Better Supporter

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    If I read into it correctly about twisting and forcing the air tubes into the air box, I used to try that. Then I discovered the easy/best way to do it is put the elbow into the carb. Have the short rubber hose "sleeve" just below the upper end of the elbow and hold the end up to the aluminum ring in the air box opening. Slide or more correctly work the hose section up over the joint to touch the airbox. Tighten the clamps. Naturally, removing the air tube elbows in the beginning is the reverse - hose clamps loosened, work the section of rubber hose down the air tube until just below the top edge, then turn easily and remove from the carb.

    Edit: Duh me, I just looked at the picture and realized your air box is different looking than my ST.
  3. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    Someone asked that I add this tip here. I guess I thought everyone already knew it.

    You can drill a strategically placed hole in the engine front cover that allows you to insert an Allen wrench into the alternator bolt and turn the engine for tuning without having to detach the battery or dink around with the front engine cover, oil cooler, or with the center front fairing cover on RS and RT models. To avoid the hassle, some folks bump the rear wheel around, which is less accurate and puts you not in a good position to see the timing marks. Drilled to the same size as the timing hole, you can use a timing hole plug to close it up.

    [​IMG]

    [​IMG]
  4. UnclePete

    UnclePete Been here awhile Supporter

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    Neat trick .
    How close is the rotor bolt to the cover ?
    Would it be possible to use a pencil stub with eraser inserted into bolt to make mark on inside of cover , or did you measure to locate the hole ?
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  5. Malindi

    Malindi Zen Adventurer

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    After 20 years of setting carbs, I got the best tip yet from a drag racer in the US. Instead of riding the bike warm and then turning the carbs, ride the bike warm and then let it sit for 30 mins, don't immediately dive in with the balancer etc. ... it allows all the bits to cool down somewhat and for some reason makes for a better balanced bike. I've also figured out (all by myself) that to start with a new carb rebuild, I lean over the bike and touch both stops, then have someone very, very slowly turn the throttle. You can feel the differential in the lift from the stops. It will allow you to even out the cable lengths before you even ride it warm or start balancing the bike. Makes it easy and most times you are very close to spot on with the balancer.
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  6. Disston

    Disston ShadeTreeExpert

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    I haven't done this but I think a short stub of chalk would work better. Distance is maybe less than an inch?

    Malindi, carb tuning trick sound cool. Bet it's to be the new most quoted tip on the forum.
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  7. Plaka

    Plaka Brevis illi vita est

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    Childrens play dough works well. Put a thin smear of grease on the rotor so the clay will not stick. Clean the inside of the cover so it will. Make a patty cake out of the dough and mount it in the cover. It will take an impression of the hex hole in the bolt and you will have a very accurate location. Measure the thickness and engrave it on the inside of the cover for the next time you pull the flywheel.

    I got 5 sticks of dough, wax based, at the dollar store for a dollar. It is proving to be very handy stuff. Better thn the oil based clay I used to have. It does not make a mess.
  8. Plaka

    Plaka Brevis illi vita est

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    I can set the idle balance on my carbs in a flash, all by myself. If you use the wrong tools you need tricks and helpers.
  9. Malindi

    Malindi Zen Adventurer

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    :ear
  10. Plaka

    Plaka Brevis illi vita est

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    Set everything to nominal, that will get it idling. Idle it and short one side, the other shout hit 3-4 times then die. Adjut stop to get this. Now short the other side, same thing. When you go for your test ride (I do 100 miles) carry a small screwdriver in your pocket and touch up the ile if needed turning each side exactly the same amount. I have a screwdriver with a line filed across the butt so I can see how much I am turning it.

    There is another trick but I'm still working on it.

    On a freshly rebuilt carb the idle stops should already be set to nominal. You do it on the bench where it is easy. Everything should be set to nominal. You should be able to mount the carb and have the bike idling right away.
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  11. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    Neat trick. I simply measured it. You know it is centered horizontally and vertically you can measure from the cover mounting holes. In your favor is that when sized to fit the timing plug, it is enough larger than the hex wrench that you can be wrong a good bit and it will still work well. I didn't measure the distance, but I'd recall it at less than 10-12mm.
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  12. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    If you have no helper (I never do - no-one will play with me) you can feel one and watch the other while twisting the throttle.
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  13. Malindi

    Malindi Zen Adventurer

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    Maybe, but I've never been able to do that right. The movement is so subtle... The key is that once the cable slack is taught more or less the same on both sides, the rest of the variance is small (for the manometer to deal with)
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  14. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    Here's an obscure trick that I just figured out today. I am bringing a friend's 86 R80RT out of a 14 year slumber and thought it wise to dismantle the forks and see if any of the o-rings still existed. Well, when you withdraw the damper rod, the BMW 31 42 1 452 013 "GUIDE RING" (Key #9 in the drawing) comes out of the slot in the BMW 31 42 1 452 012 "ABSORBING PIECE" (Key #8 in the drawing). Haynes calls the "ABSORBING PIECE" a "PISTON" and the "GUIDE RING" a "PISTON SEAL" which makes much more sense.

    [​IMG]

    BMW has a special tapered tool to re-introduce the piston and seal into the sharply stepped interior of the fork tube. Lacking that, Haynes suggests that you slide a couple of feeler gauges in to try to urge the seal to compress and go into the fork tube. How long does it take to figure out that THAT is not going to work? No, less than that. After giving up on the Haynes method, I decided to employ some Rescue Tape, which in itself is its own trick. This stuff has no adhesive, is stretchy, and sticks only to itself. Just go get some.

    https://www.amazon.com/Rescue-Tape-...e&qid=1555884766&s=gateway&sr=8-1-spons&psc=1

    I decided to wrap the lower half of the Key #9 Seal tightly to the #8 Piston in order to get it past the square edge inside the fork tube.

    [​IMG]

    Once the leading edge was in, I cut the Rescue Tape and withdrew it from the inside of the tube.

    [​IMG]

    Then I could push the damper rod piston easily into the bore.

    [​IMG]
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  15. WRC51

    WRC51 Long timer

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    I used the feeler gauge method when I re-did my forks. I actually used three feelers one for each ring gap as it went into the fork slider. When I read it in the manual I didn't think it would work but it was almost too easy. lol
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  16. Malindi

    Malindi Zen Adventurer

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    Lacking fancy tape, I did it with a piece of paper rolled into a tapered cone. Worked fine.
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  17. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    Beats my method. Where was Haynes with a tip that worked? Oh well, likely the last airhead I'll ever lay wrenches on.
  18. Malindi

    Malindi Zen Adventurer

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    The tip was included with the new fork stanchion I ordered from Motobins. "Why did you order a new fork stanchion?" you may wonder. Because, for some unexplained reason, the fork stanchion started to leak, after it developed a crack not visible under the lower triple tree. I kid you not. I've had this bike since nearly new (it came from Germany so has a 7 digit VIN etc., I have the original TUV and production paperwork, everything... ), it's never been down and I put about 250,000 kms on it and after I restored it, the fork stanchion started to leak.

    Attached Files:

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  19. mslim

    mslim If it's worth doing... it's worth overdoing

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    I don't know if the following works with Bings, but I use it to baseline throttle cable length on my Dellortos.
    • idle stop screws are backed out until they are not contacting the slides
    • with the air box elbows removed, insert 2 (more or less) identical sharpened pencils (longer is better) so they are being held in the carb throat by the cut in the slides.
    • slowly open the throttle and note which slide moves first
    • adjust cable length on one carb until both pencils dip at the same time
    • use manometer or equivalent to match vacuum
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  20. beemerphile

    beemerphile Unreconstructed Southerner Supporter

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    I'll try your method on the remaining fork. The flimsy "seal" had spread enough that I didn't think it would stay in the channel while I pushed it through a paper funnel. I tried a funnel made with thin plastic sheet, but it was too thick.

    UPDATE: I tried the @Malindi method and I could not get the seal to stay in its slot while it was lowered into the tube. Probably my technique error, but I"ll stick with Rescue Tape.