Engine Trouble spark plug help

Discussion in '2-Stroke Engines' started by SRPM, May 7, 2015.

  1. SRPM

    SRPM Member

    Hi all I need help with reading my spark plug and recommendations on what to do. This is my spark plug after a ride around the neighborhood with 32:1 mix in 60°f cloudy weather with stock jet and c clip on needle second form the top.
    Here a pic with the flash on and off.
     

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    Last edited by a moderator: Dec 18, 2015

  2. butre

    butre Well-Known Member

    are you using synthetic oil? how long was the ride? full throttle or part throttle?

    my guess right now is the plug heat range is too cold
     
  3. SRPM

    SRPM Member

    I'm using walmart brand Supertech 2 stroke oil doesn't say anything about synthetic; was think about switching to some Lucas syn blend. About 30min to an hour max. It varied about 3/4 throttle to almost full I like to back off WOT just a tad bit seems to run better that way too.
     
  4. SRPM

    SRPM Member

    Oh also I have the NGK B8HS because I plan on riding in 70-100°f this summer and because I saw a post from Febian that he uses that one to protect against a wide range of head temps.
     
    Last edited by a moderator: Dec 18, 2015
  5. crassius

    crassius Well-Known Member

    those pics look like 2 diff plugs - assuming the last pic is without flash & looking like real life, I'd say you were OK if the motor is still in the running in phase, as it will get leaner when the rings seat

    if the motor has 300 miles on it, I'd say you're a bit rich
     
  6. SRPM

    SRPM Member

    Yes last pic is flash off. Same plug. Break in was done 2 tanks ago and was done with about 2 and a half to 3/4ish tanks of 16:1 and has about 200-250+ mile not exactly sure my bike speedo stopped working little over 100 miles in. Do you think engine is running good?

    Going of topic a bit. I found a leak around the crank case bolt; the one above the magneto right under the gasket for the jug on the front end of motor. Do you guys think I'm ok to run it like that that, if so how much power am I losing? Any ideas on cheap and easy fixes to this problem I'm on a super tight budget right now. Anything help. Thanks
     
    Last edited: May 7, 2015
  7. crassius

    crassius Well-Known Member

    that leak is fairly common on some motors - not serious and can often be fixed by just adding a very small washer to that bolt
     
  8. SRPM

    SRPM Member

    Ok cool thanks for the info I might have to try that. Now back to this dang spark plug.
     
  9. butre

    butre Well-Known Member

    You definitely want a B7HS or B6HS, the 8 is too cold for your engine. Fabian is a lunatic who does full throttle up steep grades at 20 kilometers per hour, so his engines get pretty hot. His knowledge is good, but it's all experience based and his experience is different than that of everyone else. Next time, get a second opinion.

    Keep the 8 around, it might help once it does get to be 100 degrees, but it's just not time for that yet.
     
    SRPM likes this.
  10. SRPM

    SRPM Member

    Ok well that kinda sounds like me, but I bought four of the 8s so I'll return the other three and get one 7 and one 6 should I just get two of each or which one would be the better of the two so I can get extras. Would the 7 be better for the hot weather and 6 for cooler weather,
    Thanks
     
  11. Slogger

    Slogger Member

    Hi man,
    Just get one of each, they last about forever, really. Clean and check the gap occasionally.
    I ran a 5 in the winter cold, a 6 when it got into the 50's and a 7 now. An 8 might be good in the heat of summer in the desert. I think the 7 is cold enough, myself.
    It gets into the 90's around these parts, not too bad but pretty warm.
     
  12. SRPM

    SRPM Member

    Thanks but I just found out the store doesn't have the B6HS only the B7HS's so I'm going to het a couple of them.
     
  13. SRPM

    SRPM Member

    Just got back from the auto parts store with two of each NGK B7HS and B6HS what would you recommend for a ride to work in the morning weather says it's going to be about 50°f. Thanks rpms
     
    Last edited by a moderator: Dec 18, 2015
  14. Slogger

    Slogger Member

    How hot will it be coming home?
    ;)
    It isn't all that critical. The higher numbered plugs transfer more heat out of the combustion chamber so they are 'colder' running plugs. On the old NGK site I think it was 50 degrees C difference for each step. The 7 runs 50 degrees C cooler than the 6. Colder plugs are for high rpm running in hot weather. Too cold of a plug will start fouling at low speeds and having long warm-up times.
    A hotter plug is fine in cold weather for putting around, never working the engine hard. Hard running with too hot of a plug can burn a hole in the piston.
    The 6 or 7 should be fine.
     
    SRPM likes this.
  15. SRPM

    SRPM Member

    It says about 60°f from the ride home. Its up hill basically both ways the first hill I have to pedal with the engine to get up the other one is less steep but I still have to pedal a bit to help it along.
     
    Last edited by a moderator: Dec 18, 2015
  16. kerryh

    kerryh New Member

    Hi guys, I'm reading this with great interest. I live in phoenix where it is common to be 115-120F daytime and not less than 90 even at night. I'm using a 6 at about a 24:1 ratio to try to compensate. should i also be running an 8? (didn't even know they were sold...)
     
  17. SRPM

    SRPM Member

    If you read Sloggers post before my last he says
    so a 7 would keep your engine 50°c cooler and the 8 should be 100°c cooler if my understanding is correct. My problem it seems was I was running to cold of a plug on to cool of a day. I would try it out couldn't hurt, but I would also get a second opinion.
     
    Last edited by a moderator: Dec 18, 2015
  18. Slogger

    Slogger Member

    I would.
     
  19. Slogger

    Slogger Member

    Not the engine, just the combustion chamber temps, all other factors being equal. If you have too lean a fuel air mixture it will over heat anyway, for instance.
     
    Last edited by a moderator: Dec 18, 2015
  20. SRPM

    SRPM Member

    Oh but doesn't combustion chamber temp effect engine temp. If combustion chamber is running cooler then less heat is applied to engine right?
     
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