Fast Carb Question

Discussion in 'Old's Cool' started by Stagehand, Mar 16, 2007.

  1. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
    Oddometer:
    27,368
    Location:
    Shawangunks
    thanks for asking-- yeah, we got it out. Lots of kicking and screaming. That bad boy was IN there.
    I assume the outer case of the slide is aluminum. The central shaft that is pressed in is steel. the retaining screw is aluminum.

    Pics for your Amusement

    The piece in question:
    The object here is to replace the needle

    [​IMG]

    End view after trashing the head, but not getting any love:

    [​IMG]

    The retaining screw after eviction:

    [​IMG]

    Recently Divorced couple:

    [​IMG]

    I think the slide survived the surgery, although obviously the retaining screw did not.

    [​IMG]
    #21
  2. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
    Oddometer:
    27,368
    Location:
    Shawangunks
    OK--Dat, I was gonna PM you, but this might be good for a laugh, and I dont need to gack up another perfectly good thread, so I'll just put this here:

    I did a carb rebuild, and recently put them back on the bike. Did a valve adjustment to make sure all was well, didnt touch studs, discovered some lash, gonna fix it later-- yadayada, OK.. lets see if the damn thing STARTS FOR CRYINGOUTLOUD


    Checked plugs, they were carbon black with about 100 miles on them since new.
    [​IMG][​IMG]

    Started up great.
    I left just a little cable slop at the carb side ferrules. Choke and throttle pulling even within reason.

    I think I am mistakenly out at 1/1 turns instead of 1/2 and 1/2 idle/air. Anyway, I got it to Idle pretty well around 1000, using even turns on both sides, so I took it for a ride. I put about 20 miles on it, and ended up at a car wash. :eek1 I figured I'd clean it a bit.. it hasnt been washed off since the race, and me trying to do a valve adjust in the dark w/a headlamp and knocking dirt onto the gear was making me NUTS [​IMG] so I broke down and washed it.
    It did not melt! :eek1
    [​IMG]
    on the way home, it acted like one cylinder wasnt firing. OK, I'm relatively used to that, it just got a bath, and it hates baths ... i fiddle with the plug wires and whatnot. Everyonce in a while on the mile home it sputters like the second cyl is kicking in, but I cant tell exactly which one is not firing.

    I get it home, shut er down, and first thing I do is just handle, manipulate the carbs. I grabbed them and just wiggeld. the right side is tight, but left has some play at teh carb/cyl joint, and I hear a "whoosing" noise when I torque the carb sideways...

    OK-- so I think-- easy- air leak. Tighten down all hose clamps. That worked really nicely.

    Now I pull the plugs. Right side is the same. Black, but not wet.

    [​IMG]
    left side is Pink. electrode and ceramic. and HOT now that you mention it.. I was able to just loosen the right side with a wrench and finger turn it out, but the left side is HOT, and I have to wrech it all the way out.
    I dont know why, but my gut says the left cyl is lean. so my solution is to back the air screw on the left side off two "notches" in the snowbum sense off of tight. So now the left side air screw is 1 turn and two slot widths. right side is 1 turn.
    Hit the starter button, and it works great. Both cyls kicking nicely. Do a few laps of the driveway, nothing really, just 90 seconds of figure eights. Runs great. I didnt do the adjust with the engine running.

    Shut down, check plugs, no change Right. Tiny bit carboned on left.


    Carburettors are Magic. :lol3


    I neglected to peen the throttle plate screws, so I have to pull them back off again to do that now that I know I've got them in properly.

    I'm going to reset the air screws at 1/2 turn. and start over. When the Twinmax gets here, I will continue this process.

    Pics of Plugs uploading.

    So how far off am I, so far?
    #22
  3. datchew

    datchew Don't buy from Brad

    Joined:
    Aug 1, 2005
    Oddometer:
    7,409
    Location:
    Remember the Alamo!
    to me, it seems so far so good.
    I know people ride through rivers and stuff, but cold water on a hot engine makes me cringe. but then, I ride in pouring rain, so there's my hippocrisy.

    I'm kinda clueless but curious on that whooshing sound, especially if that was while the bike was shut off. Unless the piston was just in the right position and there was some pressure or suction in there or soemthing that you released.

    I can't speak for other people's carbs, and I'm lacking in experience on motorcycle carbs, but i've worked on alot of vw carbs over the years. Different carbs will perform differently even if the mixture screws are at the same point. So don't take any specific mixture screw setting as gospel. My gut tells me these bings are no different and unless you're way past the normal amount of turns, don't worry about it and just tune it to where the bike is happy.

    Bing carb Guru's can hopefully chime in on this one.

    Have you tested your plug wires with a multimeter (should be 5k-ohm)?

    Unlike car carbs that feed the whole engine, in my experience, these 1-per-cylinder models are different. On my truck for example, once warmed up, you slowly close the mixture screw and the whole engine will literally start to stumble and die when you get to just past the right mixture. It's very noticeable.

    On my bings, when warmed up, i can completely close either carb mixture screw on either carb and the thing will still run. It's a very subtle point when you get just the right mixture point and start to go past it. You have to listen for the cylinder you're tweaking to kind of "dim" or fade out.

    Otherwise, going by plug color works as well but will take longer and burn more fingers. I don't really know which is better, but I know which is easier. :deal
    #23