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NGK iriduim plug making me bounce of rev limiter?

1832 Views 5 Replies 4 Participants Last post by  fossil
Last week before my ride this past weekend I installed a NGK iriduim plug. I did not adjust the gap on the plug before installing it, as I was told it was pre-gapped. On the trip this weekend the bike ran great, however, it was baffling back through the snorkel at full throttle in 1st-4th but not 5th. Remember I have an S, not an ES. So I was manually shifting the gears myself. The spark plug was the only thing I changed, but could he just be throwing so much spark it was making the engine bounce off the rev limiter at full throttle in those gears? It did not sound bad, just like a car letting off at full throttle. I have my idle speed set kinda high, I wonder if slowing it down might help. Any ideas on what it might be?
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I've never noticed a bit of difference with the Iridium plugs, (out of seven wheelers), only reason I run them is because they don't foul. I doubt the plug effected the running characteristics at all; if the heat range is the same I would start looking somewhere else.
No, I am almost 100% certain its the plug. I know they throw more spark, I was wondering if that is why it was making that sound. I have see where a 10hp briggs and straton motor went from like 8.7 hp to 9.2hp just by changing the plug. When you refer to heat range are you refering to the actual engine temp of the bike? Because it would do it if it was totally cold or if I had been running all day. Anybody have any more ideas?
I noticed mine hit the rev limiter more this weekend after I added the NGK Iridium plug and I added a new air filter! I guess it makes it turn up faster or somethin!
Huh, that's wierd. I have never noticed any difference........anyway, when I talk about heat range I mean the plug, not the engine temp.
Only advantage to irridiums is longer life out of the plug. Performance wise you wont notice a difference. other than the "placebo effect". Spark strength is controlled by the ignition coil itself. Modern cars and trucks use them so they can get 160,000KM out of the plug as it is an emissions warrantable item and manufactureres dont want to be replaceing spark plugs under the 5 year 80000KM emissions warranty that is mandated by the govt.
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