Weird Plug Gap Problem

Discussion in 'Electrical' started by SdCruizer, Feb 9, 2012.

  1. SdCruizer

    SdCruizer Member

    I bought a ngk plug from reading on here which type to get. I put it in and it was running weird at low power almost like it was skipping.
    So I checked the gap areound 23-25 cant remember.
    I put in the china plug and it ran normally. But the gap on that is 50.
    So I gapped the new plug to 50 and it seemed to run fine. But I only went around the block.

    Few days later I took it on a long ride and noticed hill climbing was slower. So I lowered the gap slowly until what im at now I think its 30. Seems to sound and run better.

    So my question in should I experiment more with the gap?
    Or what do you all have. My friend just got an engine so I checked his gap, it was around 30 also.
    What does the larger gap change?

    Wonder why mine originally was at 50 and seemed to run great for the 1-1/2 tanks I put through it. Then adding a name brand plug at the same gap didnt run too well up hills

    Unless the china plug was a different temp I think the only markings on it is BB

  2. SdCruizer

    SdCruizer Member

    got it down to around 30
    runs good that way, so maybe I wont mess with it
    just dont understand how the stock seemed to run great at such a large gap
  3. Al.Fisherman

    Al.Fisherman Active Member

    After posting all the information I don't see what plug you bought.
  4. SdCruizer

    SdCruizer Member

    whatever was recommended ngk b6 something
    its posted all over this site the exact one to use
  5. HeadSmess

    HeadSmess Well-Known Member


    thou? mil?

    tenths of a thumb?

    stick ya gap at 1mm and leave it seems to work most of the time...

    wow, i havent looked at my plug for a good 800km... :jester:
  6. SdCruizer

    SdCruizer Member

    one of those round keychain gap tools
    I have no idea what scale it was
  7. Al.Fisherman

    Al.Fisherman Active Member

    Scale = thousands
  8. SdCruizer

    SdCruizer Member

    I checked .030 I believe
    I saw on the back of my gauge it shows mm
    so 1mm would be around .040

    I think my friends stock plug came set to .030
    Im just wondering why my stock plug was .050

    one question is what does enlarging or shrinking the gap do for a 2 stroke?
  9. Al.Fisherman

    Al.Fisherman Active Member

    The closer the gap, the easier the plug will fire, BUT it might not produce a good enough spark to fully ignite the fuel.

    Last edited: Feb 11, 2012
  10. SdCruizer

    SdCruizer Member

    did some experimenting with the gap and jetting because of my new filter
    got some speed runs

    in the end the .040 or 1mm gap has given the best top speed but I did not go larger then that with the gap
    tested with .035 and .030
  11. HeadSmess

    HeadSmess Well-Known Member

    going too small increases the chances of a misfire due to carbon deposits or just plain gunk flying around (it can and WILL!)

    going too wide places too much load on the ignition system, and it will either burn out or find the path of least resistance. which is usually NOT across the plugs gap!

    1mm. a thou is 0.0254 mm, 1mm is 39.4 thou.

    anything from 25 to 50 is fine... you dot even need a feeler gauge, just a geusstimate :)

    you will have more satisfaction finding out how a tuned pipe works and making one, or how the CDI works and wow...making one, than mucking around with the plug gap. the reults are far more worthwhile :)
    Last edited: Feb 12, 2012