As you know, we suggest using the NGK BPR6ES plug.
The 8 in your spark plug number indicates that spark plug is "colder" than the 6 we are using on the fuel injected UCE.
NGK temperature numbers are somewhat backward from other companies. Low numbers are hot and high numbers are cold so the tip of a #2 would run very hot and a #9 would run very cold.
The colder #8 you have found may develop carbon buildup on its center electrode even though the engines fuel/air ratio is correct. The carbon buildup can cause fouling problems.
As you mention, your spark plug is a iridium plug and it will probably set you back a bunch of dollars.
Although the RE engine has been updated with hydraulic valve lifters and a automatic compression release it still is an old fashioned, low reving, OHV pushrod engine that works just fine with a standard old fashioned spark plug like the NGK BPR6ES that only costs a couple of dollars.. No need for a expensive spark plug with this engine.
For the price of one iridium plug you could buy 3 standard plugs so you would have 2 spares if you ever need them.
Topic: Gday from Canberra, Australia (Read 2435 times)