High Compression Plug?

Discussion in 'Performance Mods' started by geebt48cc, Mar 15, 2013.

  1. geebt48cc

    geebt48cc Member

    Well, I'm trying to figure out if the NGK iridium plug BR9HIX is a good choice????? I've always used the regular NGK B5's and B6. Does anybody know about the BR9HIX??

    I could also use a little longer plug for that very small compression boost??????????????????? Anyway, the NGK BR9HIX?
    Last edited: Mar 15, 2013

  2. Samdallas214

    Samdallas214 Member

    I have never used the BR 9 but got to say NGK's always rank #1 so if it's an NGK it's got to be good
  3. IbedaYank

    IbedaYank Member

    to long of a plug and you will get a brand new light weight piston... the kind with holes where there should not be
  4. Fabian

    Fabian Well-Known Member


    With some high compression cylinder heads, you need to index the spark plug so the ground strap (otherwise known as the ground electrode) faces the top of the combustion chamber, otherwise you'll have piston to spark plug interference, and that's with a normal length plug.

    The standard low compression cylinder head can take any extended reach spark plug like an NGK BP6HS.
    geebt48cc likes this.
  5. geebt48cc

    geebt48cc Member

    Yes, Fabian, I'm using now with the PUCH head a NGK BP6HS. The bike does well with it, but I was reading that the NGK BR9HIX iridium plug works best on high compression Puch?! It's said that the BR9HIX helps due to it being a cooler running plug?
  6. HeadSmess

    HeadSmess Well-Known Member

    the iridium does nothing but add to the cost and makes for a plug that lasts for the life of five engines.

    the number, the number!

    low number...hot plug, cold motor.
    high number, cold plug, hot motor.
    in ngk at least.

    a hot plug gets hot, keeps itself clean. but in a hot motor, it melts! so a motor meant to take a 4 will melt 8's...
    a cold plug loses heat, needs the heat of the motor to keep clean. a motor meant to take 11's will always foul 6's...

    everything else is reaches and thread sizes...

    if its a hi comp head, then it will be a hotter motor. it will want a slightly cooler plug. meaning a higher number. so 8's or 9's. depends. do the insulator/electrodes start blistering on the 5's and 6's with extended long runs?