NGK BR7HS spark plug

Discussion in 'Electrical' started by Lockandload187, Feb 7, 2014.

  1. Lockandload187

    Lockandload187 New Member

    Is it ok to use even with the longer thread??

  2. jaguar

    jaguar Well-Known Member

    if the head allows the spark plug to stand straight up then there should be enough space for the longer plug to not hit the piston.
    Once you install it push the bike slowly to see if the piston hits it or not.
    But it isn't recommended because the longer plug disrupts the fuel mixture flow within the combustion chamber.
    Lockandload187 likes this.
  3. Lockandload187

    Lockandload187 New Member

    What NGK plug do you recommend? Or any plug for that matter?
  4. Huotalicus

    Huotalicus Member

    friend i use LD Z4JC 3 prong spark plug.... even with the break in burns all the fuel!!!! which is what you want..i have never used a ngk but have heard great things.... roughy 10-15 each great plug...huge difference in response and power even torque... with better coil and cdi you can gain more also and even gutting your exhaust for more back pressure....makes it louder too
    Lockandload187 likes this.
  5. jaguar

    jaguar Well-Known Member

    I like the Iridium NGK 7 that Sick Bike Parts sells but I think the reach is longer than normal.
    Lockandload187 likes this.
  6. crassius

    crassius Well-Known Member

    I'll often pop the head off, put in the plug and just look to see if it sticks out too far.
    Lockandload187 likes this.
  7. Fabian

    Fabian Well-Known Member

    I have had good success with the projector nose NGK spark plugs. My choice being the NGK BP8HS, but my engine typically spends most of it's life working it's guts out.

    Good advise has been given to make sure that an extended reach spark plug (like a projector nose design) doesn't hit the piston as it comes to top dead centre.
    Make sure you install the plug with the piston well below top dead centre then manually turn the engine over slowly to see if there is any mechnical interference between plug and piston.

    I have various designs (from different manufacturers) of billet cylinder heads and on two of them, i cannot use a projector nose plug due to interference problems, so i must use the "non" projector nose version.
    Lockandload187 likes this.
  8. KCvale

    KCvale Motorized Bicycle Vendor

    Specifically the NGK 5944 Iridium plug (BPR7HIX) $8.

    They will work in any Skyhawk engine straight or slat head, not sure about thinner head kits, but what I do know first hand is it is the one single thing you can do for under $10 and actually feel a difference from it, and why everything 2-stroke I build gets one as standard equipment.

    That leaves me with a 3 gallon bucket full of brand new stock and spare plugs but I don't care, I re-do the ignition wiring on all those builds too and it would be silly to let that work go to waste with a crappy plug.
  9. Lockandload187

    Lockandload187 New Member

    What brand name is the spark plug Huotalicus?
  10. Lockandload187

    Lockandload187 New Member

    KCvale please tell me your from nsw preferably in the sutherland shire!! Lol would love to get a good CDI & MAGNETO, good quality wires? Are you selling any parts? I was riding the other day and the clutch lever/ locking pin flew off like a grenade ;o
  11. Lockandload187

    Lockandload187 New Member

    Ty all for the advice + feedback. KC where are you from need repairs ;p lol
  12. HeadSmess

    HeadSmess Well-Known Member


    B= thread diameter.

    R= has internal resistor

    7= heat range

    H= thread length (the critical factor in this thread...oh. a pun. ha ha.)

    S= ngk standard series.

    its FINE. its the IDEAL PLUG. the difference in thread length you detect is one, two threads at most... not a whole 12mm like on an E series plug... if it is...somethings seriously wrong :joker:

    P (or projected electrode, as in BPR7HS) gets the flame kernel a bit too close to the piston for my liking. i do use them ,just dont buy them specifically anymore.

    CJ8 (champion stubby lawnmower plug) works just as well, but has a shorter thread and ceramic insulator than the ngk H series plug. good for one particular application i have where space is a concern. if there was a BM6H or anything like that, id use that instead...

    in NGK, a cj8 is a BM6A... B being the thread diameter, thats right for this engine too. M is that the plug is only short, 6 is heat range, and the A is thread length...just a few mm shorter than the H series.

    its really quite simple after a while, but... for now...

    stick with the tried and true B7HS (BR7HS, **5HS, *6HS... whatever... R is preferable really). the plug you have.
  13. KCvale

    KCvale Motorized Bicycle Vendor

    I am in Phoenix Arizona 85021.

    I am not a retail parts supplier or dealer, most everything I build is a custom job to the customers needs, budget, and desired style.

    In short I am having too much fun to think about producing parts for more than my own needs as that sounds like real wor.. wor.. wor.. ah you know, that other dirty 4 letter word ;-}