Airhead "Tips and Tricks"

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

  1. mark1305

    mark1305 Old Enough To Know Better

    Joined:
    Feb 7, 2005
    Oddometer:
    6,296
    Location:
    Merritt Island, FL
    Several days ago I fired up the R80 ST in the garage just to run it warm enough to idle without the choke since I hadn't ridden it in two weeks. Everything was fine for a few minutes then suddenly one cylinder started trying to drop out.

    Couple of days later checked the plugs - looked good. Opened carbs to check diaphrams and clean out all the passages with spray cleaner. I've had the idle circuit and other stuff get gunked up before from oil vapors from the breather condensing at the carb. Usually the left one. Even pulled the idle mix screws to check O-rings and blow out the idle circuits from that end.

    Put it back together, rode to full op temp. Tried to set up and synch the carbs and discovered the idle mix screw on the left carb had no effect - closed to wide open, nada.

    Thinking back through the process, I had failed to clean the idle jets themselves. This evening pulled the idle jet from the left carb - sure enough it was gunked up. Cleaned & reinstalled. Only had time to start it but it sounds right and only needs the sync steps repeated after tweaking the idle mix screws.

    So the TIP: If the mix screw does nothing, suspect clogged idle jet long with all related passages. Don't just spray it. Easy enough to pull with the carb in place and make sure it gets clean.
  2. garthg

    garthg Been here awhile

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    Which one is the idle jet?

    Do you have a pic?

    Thanks.
  3. disston

    disston ShadeTreeExpert

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    [​IMG]

    This may not be the vintage you have but they are all very similar. The idle jet is #3, it has an O-ring #2. Idle mixture is #5 and another #2 O-ring (they have the same # because they are the same size.) The needle jet is #9. The main jet is #13.

    Maybe it would be a good idea to take the carbs off and give them a good cleaning. Have a rebuild kit on hand because some parts don't make it through the cleaning sometimes. Replace the O-rings and gaskets. Would be a good idea to have a manual for this job.

    We haven't had a carburetor rebuild thread in sometime and others may be itching to do this also.
  4. Malindi

    Malindi Zen Adventurer

    Joined:
    Jul 9, 2001
    Oddometer:
    5,527
    Location:
    Vancouver, BC
    The 11 ribbed rubber gaiters used on non-G/S bikes work quite well on G/S bikes. You don't need the plastic rings on top of the forks for those boots. One trick to align the breather holes on top of the clamp is to slide a thin zip tie from above into the reed and past the boot's breather hole.
  5. Pokie

    Pokie Just plain Pokie.

    Joined:
    Apr 4, 2013
    Oddometer:
    2,025
    Location:
    Fort Collins, CO
    Bent my aluminum rear brake lever at the bevel drive (rear drive) from bouncing off a rock. I clamped it up in the vise and promptly broke it trying to straighten it. I dug around in my junk and found one from my Honda CB 450, it went straight on the splines of the brake shaft. No tapping, filing or messing about,...... straight on.

    Just in case anybody else has a need.
  6. Jim K in PA

    Jim K in PA Long timer

    Joined:
    Mar 15, 2011
    Oddometer:
    2,122
    Location:
    Pocono Mountains, PA
    Dang, Pokie. You need to post this up in the "how to flip the brake lever" thread. Jenna and I were debating the need to flip the lever to avoid just what happened to you.

    Good tip for an alternate to the 'kraut part.
  7. Thorazine

    Thorazine Likes exhaust fumes

    Joined:
    Sep 1, 2013
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    Location:
    Lanesplittin heaven--Southern California
    Clever, bump-worthy advice. :freaky
  8. 685

    685 Scarred Adventurer

    Joined:
    May 6, 2009
    Oddometer:
    1,081
    Location:
    Tucson (east side) AZ
    I haven't had a chance to run through the past sixty two pages, so if this has been previously covered, scuse me.

    The charging system hasn't been doing its job well lately, '76 r90/6, not really charging at all, so a major diagnostic session was in order. Rotor checked out fine, Stator, too, and so did the Diode board. My brother's visiting, and he did the honors. I had previously put in new brushes and an electronic voltage breaker.

    Turns out that the heat sink on the diode board wasn't grounding well. A little grounding wire from the heat sink to a bolt hole just above the alternator body and now the battery is getting 13.3 v. And the bike is running much better!

    Kind of a break through day on the old mongrel!
  9. LonerDave

    LonerDave Been here awhile

    Joined:
    Aug 17, 2011
    Oddometer:
    127
    Location:
    Lisbon, WI
    Posting this here for easy reference after having first posted in general Airheads section.

    This might be covered elsewhere. Might be very obvious to most folks. Might not be a good long-term solution. But here's a quick fix I used to get my R90/6 functioning right again for about $1 and in 20 minutes.

    The Problem - Neutral light would come on whenever I squeezed clutch lever, whether I was in a gear or not.

    Diagnosis - Several posts suggested it was the diode behind the fuse block in the headlight shell that was shorted. This diode connects terminal 85b to terminal LKK, and prevents the neutral light from reaching ground unless just neutral switch is closed. I had just finished clumsily diagnosing a bad starter relay, so suspect I fried the diode.

    Real Fix - Sources told me to remove the fuse block and solder in a new diode. Simple enough, but that means unplugging and keeping track of all those wires in the headlight bucket. And since yesterday was the first day with weather/roads nice enough to ride, I didn't like the idea of tearing into it.

    Quick Fix - Bought a new diode (3a, 400v) at Radio Shack. Crimped a male spade connector to one end and a female to the other. (NOTE: direction matters with diodes - I believe I put the male connector at the end of the diode with the band on it.) Unplugged double brown/black wires at terminal LKK, attached diode, reconnected double wires to end of diode.

    Ta da! Neutral light on only when in neutral.


    EDIT: Linky to lousy pics! http://www.advrider.com/forums/showpost.php?p=23994556&postcount=6
  10. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    backwoods Alabama
    Bravo. Good fix! The diode IIRC, is numbered 1N4001 (a 1A diode, your 3A will work).

    --Bill
  11. RagerToo

    RagerToo vroom vroom

    Joined:
    Jun 16, 2012
    Oddometer:
    310
    Location:
    NE Oh
    34 years and I guess my front brake hoses were 'used too much when they were new'. (The bike is new to me only a bit over a year+. 50k. And a shout to Max's, ordered stuff on Sat. last, got my goods Wed. afternoon, USPS.)

    The grommets are tight, well yeah. I put a spot of Kroil on them and proceeded. Shiver me timbers there's the outside groove and there's the inside groove, and I suppose I could have ground a small screwdriver soft and smooth to not mung up the grommet.

    Then I remember I had a couple of brass typewriter tools. One has a rounded "seal pic" end on both ends and the other looks just like a rounded down screwdriver on one end.

    Installed the grommet in the mounting horseshoe and shoved the new hose end in and carefully pushed the inner lip into the hose end groove, a bit at a time. And alls well.

    Noticed the left fork tube (top) is just touching the orig RS headlight mount at lock. Gotta bend it out of the way a touch, or something. I already had adjusted it. Pulled the throttle apart and re-lubed that piece of art.
  12. KhaoSanMan

    KhaoSanMan Airhead

    Joined:
    Apr 26, 2009
    Oddometer:
    618
    Location:
    Chico, CA
    I just got a new ignition for my GS, an Alpha system from Risk.

    I've never timed my bikes before, and I will need to learn. I'm also working on my VW Bug so I need to be able to set the timing for that as well.

    My questions is, what is the recommended timing light/dwell meter that you guys suggest I get? I have a friend with a good light, but I figure with al my airhead motors and my brother's and father's it makes sense to get a good light.

    Thanks!
  13. disston

    disston ShadeTreeExpert

    Joined:
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    Oddometer:
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    Location:
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    Brand is not too important. Better made units will cost more, usually. You want a unit that uses a magnetic pick up. This is the clamp that fits around the plug wire to pick up the signal. Most modern lights will have this but if you buy a used unit on Ebay or something you may get a light that has a spring that fits on top of the spark plug and the signal wire clamps onto this.

    [​IMG]

    Sorry about the size of the image. I have no control of that feature.

    This is a standard type timing light. Notice the pick up that is the pink clamp. This unit also does not have an advance control feature, something on more expensive units and that you do not need. Harbor Freight has timing lights for less than $50.

    The timing light is hooked to the vehicle battery to get power. There is another type that uses batteries in the light and doesn't cost much more.

    [​IMG]

    I've been thinking of getting one of these. I've seen them for sale at Amazon.com

    You mention a "dwell meter". This is something different. It is only used for ignitions with ignition points not electronic.
  14. KhaoSanMan

    KhaoSanMan Airhead

    Joined:
    Apr 26, 2009
    Oddometer:
    618
    Location:
    Chico, CA
    Thank you Disston!

    I bet the Harbor Freight light will be more than sufficient for my needs, I just wanted to check if there might be any major issues with them or if there was a preferred light to that one.
  15. Les_Garten

    Les_Garten Been here awhile

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    Oct 6, 2011
    Oddometer:
    744
    Location:
    PSL, FL

    Just a thought, but if you get a computerized timing light you can measure exactly how many degrees you are set at. FYI.
  16. RagerToo

    RagerToo vroom vroom

    Joined:
    Jun 16, 2012
    Oddometer:
    310
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    NE Oh
    Do you find that, I assume, what you have, is accurate?

    I have a 25-30 yr old light, with a pot/ dial for advance. Probably a no-name by now, it was from when they were first coming out. I've never relied on the advance readings to be accurate. Mostly used to just find a mark that was way out of spec. I'm not even sure I've timed my bike with it yet. :D
  17. Les_Garten

    Les_Garten Been here awhile

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    Oct 6, 2011
    Oddometer:
    744
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    PSL, FL
    This is like the one I have and it is very handy.

    [​IMG]

    Usually go around $75-$125 on Fleabay. I've had mine about 25 years or so.
  18. RagerToo

    RagerToo vroom vroom

    Joined:
    Jun 16, 2012
    Oddometer:
    310
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    NE Oh
    Aha! Shweet. I have my bike, a fully computerized (ford) Contour and my service truck, a plain, vanilla '91 Super Duty (F450), 7.3L NA diesel.

    The next thing I'll need a light for will be my 8000lb Hyster project. (oh ghod)
  19. motu

    motu Loose Pre Unit

    Joined:
    Dec 28, 2001
    Oddometer:
    4,902
    Location:
    New Zealand
    After decades of timing lights and wires to clip to batteries, getting one of these cheap things is the best thing I've done for timing.

    Timing advance worked best on the old big box tunescopes - you could dial up the degrees on the screen and know it was pretty accurate, the ones with the dial on the end I wouldn't trust....but push button electronic like the Snap-On are real good.
  20. RagerToo

    RagerToo vroom vroom

    Joined:
    Jun 16, 2012
    Oddometer:
    310
    Location:
    NE Oh
    A friend _has_ one of those _tunescopes_. SUN brand if I'm not mistaken. Big ole' dial on it, has it mostly as a display, I doubt he's ever used it.