Fellow Inmates, help a newbie get his bike running good, pleasssee.

Discussion in 'Airheads' started by Yachtie, Nov 1, 2012.

  1. Yachtie

    Yachtie Been here awhile

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    Have a timing Light, have a good idea how to use it thanks to Tim but won't turn down any more advice.

    thanks so much for the help and advice! i'm going to spend the day tomorrow messing with it again. Thanks!
    #41
  2. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    Next time take the timing light with you and when it starts backfiring etc pull over and check that you are getting full advance and that it returns to the S mark at idle. Could be a sticking advance unit... Did you try adjusting the carbs a bit richer at idle like I said?
    #42
  3. Yachtie

    Yachtie Been here awhile

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    Did that, found that sweet spot as Tim put it. Seemed to let the bike idle better but the stumbling under throttle persists...
    #43
  4. disston

    disston ShadeTreeExpert

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    As BB says you can try the mixture a little richer, that's out, to correct for back firing. As strange as it sounds a lean mixture will cause back firing.

    Puzzle, puzzle, puzzle. Eventually you will learn this stuff.
    #44
  5. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    Yeah, that's what I was thinking; less restrictive air filters pulling less fuel.
    #45
  6. Yachtie

    Yachtie Been here awhile

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    Any further out then where i set it and it starts stumbling

    Now i am far from being the one to pinpoint this, but here's my theory. I think its fuel.

    When the bike sits these last few times running it, the fuel bowl has been full. So the 20 minutes that seem to run great starting up the first time is prolly just do to the full fuel bowl. Then once this runs out it starts stumbling due to not getting enough fuel? Could that be it? If that could be it, what would cause this? But more than likely its not, but i was just thinking about that over dinner.
    #46
  7. disston

    disston ShadeTreeExpert

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    I didn't know you have other than a stock air filter. If you now have the mix screws out as far as they will go with out stumbling I guess they are rich enough tho.

    So we now think, or we now know the timing is correct at idle and 3000 rpm, advance? Still suspect a sticky advance unit so you are going to take timing light with you.

    The operation of the float and the float needle; The fuel is cut off by the float needle when the floats rise enough and everything is adjusted correctly but under operation the fuel is being used so the float drops and fuel flows till it is shut off again. I saw a video once, probably a film it was so many years ago. That showed the float in operation in a carburetor. The float moved FAST. It fell and rose again about 2 or 3 times a second. The fuel would be starting and stopping this often. It's an important part of the operation. We set this float level with the carbs sitting on a work bench and we imagine the carb filling to this level but in operation it is a very dynamic thing. The float bounces up and down. The needle is being Slammed into the seat. Quite different from what we think is happening Huh?

    Float level is a very important setting. There are many ways to set this but for your purpose at the moment with the carbs on the bike the fuel bowls can be dropped and the floats held up with a finger then when the fuel is turned on, only one petcock need be turned on for this, the float is allowed to descend a little till fuel flows. The fuel should flow when the parting line of the float is only a little below it's level position.

    Did you ever check for air leaks around the intake runner rubbers? The rubber tubes on the head side of the carb must not leak air, vacuum. You can spray something on them to see if it changes idle.
    #47
  8. woodgrain

    woodgrain In-Dented Savant

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    Perforated diaphragm?

    Woodgrain
    #48
  9. Yachtie

    Yachtie Been here awhile

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    I have not checked for leaks yet, but would not be surprised if they leak. They look bad. Do i need that specific piece or can i just go get the appropriate size tubing from a autoparts store and use that?

    Haven't looked into timing yet. Will do that tomorrow.

    Here's a complete list of what was installed.

    -Boxer Metal Airbox delete with K&N style filters

    -Emgo Mufflers (do have a small exhaust leak that we know of, wouldn't cause these problems right?)

    -Endurolast Charging system

    -Enduralast Digital Ignition

    -New Bosch Coils

    -New Spark plugs and wires
    #49
  10. disston

    disston ShadeTreeExpert

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    Small exhaust leak probably not the problem.

    Intake runner leaks could be the problem. You can make tubes from some rubber hose. I have done this with radiator hose. Don't know if it will last in the environment of air/fuel moving through it. The stock runners are not too expensive if I remember correctly still something else might work for now.

    Timing both idle and advanced needs to be correct. The sticking of advance unit should be checked. These could be the problem.

    So the valves are done huh? Progress..:D
    #50
  11. Yachtie

    Yachtie Been here awhile

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    I'm still not 100% confident i did the valves correct, going to re check tomorrow.

    This is where I'm confused with valves

    I used the clutch and allen wrench to turn the motor to TDC. When i saw the TDC mark through the hole today the right side was the only side that seemed to be where you guys said i should see the intake valve just starting to come back out. So i adjusted the right side. Left Alen key where it was, spun complete 360 and oncethe allen came around and the TDC was visible or almost visible the Left side Intake Valve was not to the point of coming back out nor was it even compressed in. I'm going to fiddle with it some more tomorrow, but thats whats i remember seeing off the top of my head. Again, prolly was just doing something wrong.

    And then theres the tick i'm hearing, you can clearly hear it from 20-25' away. That normal?
    #51
  12. hardwaregrrl

    hardwaregrrl ignore list

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    Tappy valves are happy valves. Best way for a FNG to see which side is at TDC is to spin the pushrods. If they spin, you're on the right side.

    #52
  13. Byron1

    Byron1 Been here awhile

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    I should start this by saying I am by no means an expert. Also a noob to airheads.

    Anyway: When you say clutch, I assume you mean the rotor. Turning this 360 degrees does not turn the crank a full 360 I do not believe. Don't base your turning the engine over 360 on the movement of the Allen key.

    Sounds like you are getting the first cylinder correct. Once you have done that turn the rotor with Allen wrench until you see the intake on the other side open then close.. Look through the timing hole and get the OT mark.

    Haven't read the entire thread but saw someone mention diaphragms too. . You can check that by getting the bike running and then revving the engine individually on each cylinder by pulling up the throttle cable on each individual carb one at a time. If it increases revs fine on the first side you try chances are that sides diaphragm is ok. Repeat on the other side, if that side stumbles then it is likely the diaphragm in that side is gone. Someone with more experience of this may shoot me down here, but this is how I was told to do it.

    But, just to repeat what has been said before I wouldn't look at that until you are sure you have a good basic state of tune.

    Good luck. The guys and girls in this forum are a great bunch so sure you will get it sorted before long.

    Good luck!
    #53
  14. disston

    disston ShadeTreeExpert

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    Nope, nope, nope. You've got the valves wrong. OK? Please try to get this the way it is put down. I will be as simple as possible. If I can.

    Spark plugs out. Ignition off. Transmission in neutral. You are going to use the Hex key in the alternator rotor method of turning the engine. The alternator rotor is attached to the end of the crank shaft. Turning the alternator rotor 360 degrees turns the crank 360 degrees. (the ignition is attached to the cam shaft which turns 1/2 crank speed) (we don't care about that when setting valve lash)

    We are going to set the valves on the left cylinder first. Take the valve cover off the left cylinder. Turn the crank with the Hex Key in the rotor till you see the valves operate. Do this as many times as you like. Notice they are a machine. They work only one way. They open and then they close. They have a certain order and timing to this operation you need not concern yourself with this at the moment. Watch the intake valve. Notice it will open, as in the rocker tip pushes it open, then it will close, as in the rocker allows the valve spring to close the valve. Once the intake valve has just closed. (get that correct, it is not closing, it is not going to close but the intake valve is closed) I'll say this again, Once the Intake valve has just closed it is time to look in the window for the TDC timing mark. It will be almost a quarter turn of the crank away from the point the intake vale is finished closing. But no mater how far away you think it is it is the next TDC mark.

    edit; I say above the crank will turn one quarter turn after intake closing for TDC to appear. This should read one half a turn, or 180* It will actually be a few degrees short of 180 but that is another issue.

    I'll add a little explanation. The intake closes in theory at the bottom of the intake stroke of the piston. The downward moving piston has sucked it's air and fuel into the cylinder and filled the space of the cylinder as much as it can with the piston at the bottom of it's stroke. So the intake closes and the piston can now compress the air/fuel on the compression stroke. The piston comes up TDC after the closing of the intake and now both valves are closed. They are as closed as they are ever going to be because the spark plug will fire just before TDC and the piston will be sent down on it's power stroke. In order for the air/fuel to burn and the heat expand the gases and thus push the piston down...TaDa..the valves have to be closed. In order to set the valve lash we need to have the valves...closed. They are closed at TDC but only TDC on the compression stroke.

    OK? That is it. After you do the left cylinder you can rotate the crank again exactly 360*, watch for the mark in the window. For the right cylinder you only have to rotate the crank 360* and you don't have to watch the valves, if you got the left one right to begin with.
    #54
  15. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    I might suggest that you are in over your head. Basic maintenance is not difficult, but you have to have a background and knack for wrenching. And at least a shop manual. You might want to tke the bike ot an experienced airhead mechanic and get these initial problems straightened out while you are learning to work on the machine.

    --Bill
    #55
  16. oregoncoast

    oregoncoast Smells like Bacon

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    Did you ever check the plate contact on that electronic ignition as suggested??
    #56
  17. rufusswan

    rufusswan Been here awhile

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    I wonder if you couldn't simplify the task if you would remove BOTH valve covers and then center the TDC mark in the window. At that point one side will be set proper for valve adjust and the other won't. Then you can rotate 360 and the sides will 'switch'. Do that a couple of times and the problem may sovle itself.
    #57
  18. Yachtie

    Yachtie Been here awhile

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    So looking again, The TDC mark actually comes into view I would say halfway into the intakes valves closing cycle On Both sides.
    #58
  19. Byron1

    Byron1 Been here awhile

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    Sounds like someone has had the flywheel off at some point and not put it back in its proper position?!
    #59
  20. Yachtie

    Yachtie Been here awhile

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    yeah, just reading through the ignition installation instructions and they said rarely it happens but its possible. Should i even ask how that can be fixed?
    #60