Search by Motorcycle
Search by Motorcycle

NGK Iridium Spark Plug BPR7EIX

$12.03 12.03
In stock
Part
50-5944
  • Buy 10 for $10.76 each and save 11%

NGK Iridium Spark Plug BPR7EIX with a 14mm thread. OEM: 4055

Resistor plug for radio interference. Used with caps without resistors. The equivalent to the NGK BP7ES but with an Iridium Plug with a 5k ohm resistor to reduce RFI. If you need a colder plug use the BPR8EIX

While Dyno testing a problem bike (a Yamaha TX750) it was discovered using Iridium spark plugs caused the engine to gain 2 HP. Further Dyno testing on other stock and modified 650's showed the same results! The gain seems to be from improved combustion chamber flame front spread in the 650's old style combustion chamber. The same results were obtained on engines with points, factory TCI, and Boyer ignitions. We determined that the shape and position of the nose and electrode caused the gain and not any enhancement of spark. Smoothing of the dips in the power curve, increased acceleration, reduced fuel consumption and up to 4 times longer plug life can also be expected. Dyno testing performed by Heiden Tuning in Germany.

Is Universal Part: No

OEM Number(s): N/A

Motorcycle Fitment:

  • 1980 Yamaha SR250 SR250G
  • 1981 Yamaha SR250 SR250H
  • 1981 Yamaha SR250 SR250TH
  • 1982 Yamaha SR250 SR250J
  • 1979 Yamaha SR500 SR500F
  • 1978 Yamaha SR500 SR500E
  • 1980 Yamaha XJ650 XJ650G Maxim
  • 1983 Yamaha XJ650 XJ650K Maxim
  • 1981 Yamaha XJ650 XJ650H Maxim
  • 1982 Yamaha XJ650 XJ650J Maxim
  • 1983 Yamaha XJ750 XJ750K Maxim
  • 1981 Yamaha XJ750 XJ750H
  • 1982 Yamaha XJ750 XJ750J Maxim
  • 1982 Yamaha XS400 XS400J Maxim
  • 1979 Yamaha XS400 XS400F
  • 1980 Yamaha XS400 XS400G Special 2
  • 1978 Yamaha XS400 XS400E
  • 1983 Yamaha XS400 XS400K Maxim
  • 1981 Yamaha XS400 XS400H
  • 1982 Yamaha XS650 XS650J
  • 1979 Yamaha XS650 XS650F
  • 1977 Yamaha XS650 XS650D
  • 1980 Yamaha XS650 XS650G Special II
  • 1978 Yamaha XS650 XS650E
  • 1983 Yamaha XS650 XS650K
  • 1976 Yamaha XS650 XS650C
  • 1981 Yamaha XS650 XS650H Special II
  • 1979 Yamaha XS750 XS750F
  • 1977 Yamaha XS750 XS750D
  • 1978 Yamaha XS750 XS750E
  • 1981 Yamaha XS850 XS850H
  • 1980 Yamaha XS850 XS850G
  • 1984 Yamaha XV1000 XV1000L VIRAGO 1000
  • 1985 Yamaha XV1000 XV1000N VIRAGO 1000
  • 1988 Yamaha XV1100 XV1100U VIRAGO 1100
  • 1989 Yamaha XV1100 XV1100W VIRAGO 1100
  • 1990 Yamaha XV1100 XV1100A VIRAGO 1100
  • 1986 Yamaha XV1100 XV1100S VIRAGO 1100
  • 1987 Yamaha XV1100 XV1100T VIRAGO 1100
  • 1984 Yamaha XV700 XV700L VIRAGO 700
  • 1985 Yamaha XV700 XV700N VIRAGO 700
  • 1986 Yamaha XV700 XV700S VIRAGO 700
  • 1987 Yamaha XV700 XV700T VIRAGO 535
  • 1981 Yamaha XV750 XV750H VIRAGO 750
  • 1982 Yamaha XV750 XV750J VIRAGO 750
  • 1983 Yamaha XV750 XV750K VIRAGO 750
  • 1981 Yamaha XV920 XV920RH Virago
  • 1982 Yamaha XV920 XV920RJ Virago
  • 1983 Yamaha XV920 XV920K VIRAGO 920
  • 1991 Yamaha XV1100 XV1100B VIRAGO 1100
  • 1994 Yamaha XV1100 XV1100F VIRAGO 1100
  • 1995 Yamaha XV1100 XV1100G VIRAGO 1100
  • 1996 Yamaha XV1100 XV1100H VIRAGO 1100
  • 1997 Yamaha XV1100 XV1100J VIRAGO 1100
  • 1998 Yamaha XV1100 XV1100K VIRAGO 1100
  • 1999 Yamaha XV1100 XV1100L VIRAGO 1100
  • 1992 Yamaha XV1100 XV1100D VIRAGO 1100
  • 1993 Yamaha XV1100 XV1100E VIRAGO 1100
  • 1973 Yamaha TX650 TX650
  • 1974 Yamaha TX650 TX650A