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Spark Plug - 14mm - BPR7EIX - NGK - Iridium

$11.95
In stock
Part
50-5944
  • Buy 10 for $10.76 each and save 10%

OEM: 4055 - NGK Iridium Spark Plug

14mm thread.

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

Adds a solid 2 HP to your 650  

NGK Iridium Spark Plugs - Cheapest horsepower you can buy for your motorcycle!

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.

Fits the following:

MAKE YEAR ENGINE CLASS MODEL
YAMAHA 1980-1982 250 SR250
YAMAHA 1978-1979 500 SR500
YAMAHA 1980-1983 650 XJ650
YAMAHA 1981-1983 750 XJ750
YAMAHA 1977-1984 400 XS400
YAMAHA 1977-1983 650 XS650
YAMAHA 1976-1977 650 XS650
YAMAHA 1974-1979 750 XS750
YAMAHA 1980-1981 850 XS850
YAMAHA 1984-1996 1000 XV1000
YAMAHA 1986-1990 1100 XV1100
YAMAHA 1991-1999 1100 XV1100
YAMAHA 1983 500 XV500
YAMAHA 1984 500 XV500
YAMAHA 1984-1996 700 XV700
YAMAHA 1981-1990 750 XV750
YAMAHA 1981-1983 920 XV920
More Information
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