what plug is best to replace stock

Discussion in 'Motorized Bicycle General Discussion' started by handyjim, Mar 20, 2011.

  1. handyjim

    handyjim New Member

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    my plug is the 3 point plug the z4jc like to get better plug what type best split fire or platum any help will be great allso how do i put pic on my name on post jim in chicago ty all .trk
     
  2. rohmell

    rohmell Active Member

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    The NGK B6HS seems to be a popular plug used in place of the stock one that comes with the kit.
    It's not a 3-point type, though, it's a 'regular' type.
     
    #2 rohmell, Mar 22, 2011
    Last edited: Mar 22, 2011
  3. Nougat

    Nougat New Member

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    The three point type plugs will wear more slowly, because they have more edge to spark from, but you still only get one spark per discharge. The single point plugs are easier to gap.

    Iridium plugs wear slower, too, due to the different materials. But they also have higher resistance, which will theoretically give you a weaker spark. Same with resistor plugs.
     
  4. bairdco

    bairdco a guy who makes cool bikes

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    i've never been a fan of Splitfire plugs. when they first came out years ago some guys i used to buy honda parts from did a review of them for a major magazine.

    they put them into a mustang 5.0 engine on the dyno, and within a few minutes one of the electrodes broke off and destroyed the engine.

    as far as a 3 point plug on our engines, i think it's overkill. there's only so much (or so little) performance gain you can get on a single cylinder engine. i mean, every little bit helps, but the difference between a good NGK BH series plug and some fancy exotic plug is so minimal it's just not worth the price difference.

    that being said, i think any name brand, quality plug is miles better than the stock one. the quality is so bad i just throw them into a box and forget about them. some people like 'em, though. if nothing else, i'd change them out just for peace of mind.

    all my bikes run a 7mm copper core wire, NGK B6 or B7HS, and a nice tight boot, gapped at .030

    can't go wrong with that.
     
  5. BarelyAWake

    BarelyAWake New Member

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    Interestingly enough the "demand" for the stock China plug around here is quite high, so much so that in fact I've not a single one left - I can't seem to hang on to one fer more than a coupla days when I get a kit...

    I know a coupla performance outboard techs, greatly amused - they put 'em on the 'Wall of Shame', bring them with when they go to advanced training & certification for others to lol at & one of them keeps promising he's gonna put one on a plaque (still hasn't happend tho).

    Conclusion? The China kit plug seems quite popular amongst the skilled professionals of performance marine engines laff
     
  6. bairdco

    bairdco a guy who makes cool bikes

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    too bad i don't still have the one with the side electrode that was 1/8" off center from the center electrode. it wasn't bent, it was just, off.

    it was the first "angle-fire" spark plug i've ever seen. :)
     
  7. rohmell

    rohmell Active Member

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  8. Nougat

    Nougat New Member

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    No offense, but the first video is a series of pictures with no context or explanation, and it's an assembly operation. The second video is an episode of How It's Made, which involves manufacturing from raw materials for the first three plus minutes. How It's Made is arguably a propaganda broadcast about the wonders of American manufacturing (Bosch has manufacturing in the US); they only show the very highest quality manufacturing processes, some of which are by hand. So you're kind of comparing apples and oranges here.

    And here's a video of the assembly process of model engine spark plugs - also by hand, also in a workshop, just not in as high volume as the Chinese factory.

    I suspect that the problems with the LD kit spark plugs are a result of cheap manufacturing, materials, and design, too, not just sloppy assembly. Pointing the finger only at hand assembly operations tends to imply that people who work in those kinds of factories are somehow inherently incapable of doing a good enough job.

    These different spark plugs are also for different markets, in just the same way that a fast food restaurant fills a different market niche than a 24 hour family restaurant, than does an upscale steakhouse. In most cases, the stock plug is good enough. That it's simple and cheap in the US to replace it with a better plug and get better performance speaks to the fact that the HT engines are designed and built well enough to be easily upgraded.

    If all the cheap parts in these kits were manufactured to much higher quality standards, the HT kits would cost twice as much as they do. Motorized bicycles already have a super small niche because of 50cc scooters; increasing the price of the kits would make them unsaleable.

    Sorry about the rant, but I get aggravated when people point fingers about quality. The picture is so, so much bigger than some decent people with jobs assembling things.
     

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