Running bad and stalling

Discussion in 'General Questions' started by Neufcruz, Mar 7, 2016.

  1. Neufcruz

    Neufcruz Member

    Well I fired it up but at 1st it could rev with no load but when riding it gets up and goes but then bogs down . If you pin it or rev it up while moving it then starts to go faster. Now it dies after start and have to rev to keep on.
    I have the stock jets in Dullar carb. Jaguar Cdi is set as it comes. Running a ngk b8hs gapped at .35
    Where do I start to try and tune enough just to break it in? after that I can fine tune.
    It also has a squeak while moving coming from clutch. Stops when you pull lever in.
    Help, again!
    Mike
     

  2. bakaneko

    bakaneko Active Member

    Try gapping the spark plug lower. Sounds like a combustion/weak spark problem to me. I think your bike looks well built; I doubt it is a leak. The thing to try next is to jet the carb lean; I think the stock carbs come jet a bit too rich.
     
  3. Neufcruz

    Neufcruz Member

    Will gap at .25
    What jets should I get? Should I get a "kit" so I have a broad range to move up and down with accordingly? Do I need specific jets for the Dullar carb I have. I also have the stock carb that came with gt6 engine kit but was sold the dullar as as an upgrade.
    Why under no load it seems to rev pretty good but under throttle, from take off good but then bogs at about half throttle?
     
  4. bakaneko

    bakaneko Active Member

    Oh, I thought you had the stock carb in there. I am not sure about the Duller carb default settings. What color and texture is your plug? Can you idle? I think you are almost there just some adjustments.
     
  5. Neufcruz

    Neufcruz Member

    It idled at 1st for a bit. And after a few rides around block and turning on and off etc... She then stopped idling. I pulled the plug at .35and it was a tad wet. Put a plug I had lying around. One with 3 ends. Not sure the number and bike is down stairs now but was an 8 I think. I cleaned the ngk 8 and gapped at .25 now. Will go fire it up shortly.
    Do I need to check adjustments on jaguar CDI or not an issue till fine tuning.

    FYI. I have a high compression head, reed valve, windowed piston, expansion pipe, dullar carb, jaguar CDI.
    Once warm it fired up nicely. Even just kick starting with the pedals on stand.
    Thanks again.
    Mike
     
  6. Neufcruz

    Neufcruz Member

    Does the dellorto/dullar carb use the same type of jets from a NT carb? Want yo make sure I get the tight set.

    Mike
     
  7. bakaneko

    bakaneko Active Member

    Is it performing better?
     
  8. Neufcruz

    Neufcruz Member

    Going out now but only change is recapping plug from .35 to .25.
    Still not sure what jets to buy and the local motorbike vendor is only espanol. No compare de me!

    Mike
     
  9. Neufcruz

    Neufcruz Member

    Yes a little better at .25. Still bogging at half speed and then picks up after. Did a quick pass up to 30.2mph.
    Removed filter and same pass at 33.7mph.
    This is with a 44t sprocket so not sure How much more it could actually get.
    Anyone on if any 5mm het will work in the dellorto/dullar carb. Want to go to shop tomorrow and pick up a few different ones. I guess I will pull carb off today, remove jets and then compare before I buy.
    How many numbers up and down should I go?
     
  10. bakaneko

    bakaneko Active Member

    My thoughts is that the high compression head requires a stronger spark. You mentioned that the head was wet. Probably gas not getting completely ignited due to spark. Jetting it a bit leaner will help too. 30-34 on a 44T is pretty good and will only get better as you figure things out. Watch those revs though you are in the breaking period.

    Is your spark plug an iridium or platinum?
     
  11. Neufcruz

    Neufcruz Member

    It's a ngk b8HS
    What would be the best plug for my set up here in Miami. Weathers nice now but getting warmer/hot soon.
    I do have the jaguar CDI so it has settings for more spark.
     
  12. sbest

    sbest Active Member

    Your plug is plenty cold. If the insulator out by the tip is black and wet, move to a 7 or 6.
    No need for an iridium plug in my opinion, even platinum is a waste until you get jetting sorted out.

    Steve
     
  13. Neufcruz

    Neufcruz Member

    Picked up #60 through #69 jets today. Going to go start changing them now. Figure stock is #70 I believe and really rich so was going yo skip a few and start with #65 and then see how she feels and read plug. Not looking for optimal. Just safe and good enough to break in. Then can fine tune.

    Mike
     
  14. Neufcruz

    Neufcruz Member

    Took original jet which I thought I read was a #70 but I swear it looks smaller than the #60. Put in the 60. It didn't bog any more but seemed lean, ran it up to 64 and running way better but the plug still looks wet, mostly around the bottom side of threads, not the actual electrode.
     
  15. sbest

    sbest Active Member

    Good plan Mike.
    You can compare jets for actual size by seeing how far a sewing needle goes into them.
    The numbers are supposed to be an actual size or flow but often vary from different manufacturers.

    I really like doing mods one at a time to avoid compounded troubles.
    Plug heat range vs jetting is one of these, especially with a different head and carb.
    Too cold a plug will always look rich, so err on the hot side while figuring it out.
    Once the jet range is determined, fine tune the plug temp.
    Too cold a plug or too rich or too much oil or too cheap an oil will bring fouling, starting and bog problems.

    Steve
     
    Last edited: Mar 11, 2016
  16. HeadSmess

    HeadSmess Well-Known Member

    the size of the hole through the jet isnt the way theyre numbered... at least, mikuni etc types are calibrated on flow through the jet... not the size of the hole they drilled, which is subject to machining tolerances.

    at the size hole they use, the depth or length of it starts to affect the flow to a large degree. so they make a batch of jets and grade them by the amount of fuel that will squirt through.
    [​IMG]


    this doesnt stop you from drilling them out with number/micro drills :) soldering in bits of wire...etc. :)


    this is sorta handy... you only got clip position, main jet and slide cutaway on a stock NT carb. good enough. add in an air screw and it gets a bit more complex, like a dellorto. get a set of jets and needles for a mikuni...oh my. choices, choices, choices!
    [​IMG]
     
  17. HeadSmess

    HeadSmess Well-Known Member

    a 4 plug will definitely stay clean, may be an issue on a 35C day going up a 10km hill. doubt it.
    5-6 is fine.
    try using the BR type, with the resistor.

    you cant do decent throttle chops unless you get a new plug, and using a plug thats too cold will throw you right off.

    break in? what break in? just ride the thing like you stole it.
     
  18. Neufcruz

    Neufcruz Member

    I put the #7 plug back in (higher number is colder?)and still running the #64 jet.
    The jet explanation makes sense now.
    I have the Dellorto clone so only the jet adjustment/change. I think???
    Going to put some miles in tomorrow to get this broken in or at least get rid of this oiled down gas. Lol
    Is this carb ok or should I invest in a better one? I was told this one was good but who knows. It's definitely running better.
     
  19. sbest

    sbest Active Member

    Excellent post Headsmess.
    There is a theory that light loads and lots of oil contribute to ring and bore glazing without seating.
    That it takes intermittent moderate to high loads with moderate amounts of oil to properly seat the rings.
    My experience tends to agree with the theory and Headsmess's break in suggestion.

    Steve
     
  20. Neufcruz

    Neufcruz Member

    I should as well. It's funny, in the past with all my motorcycles, I broke them in hard and they always stood out from the rest. Now Im tinkering with this and Im concerned about break in.
    What am Zi talking about! I barely had a mile on it on the 1st day and was already doing top speed blasts. Only shirt burst but this is how I always break motors in. :)
     
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