I recently purchased some new plugs and was going to go with the NGK DCPR9EIX iridium plugs. The bike shop only had DCPR8EIX which the owner said is a "hotter" plug used by most other buell models and that it may actually help the bike run better at higher elevations e.g. Salt Lake City. Is this guy full of crap? Should I take them back and get 9's?
Hot Plugs?
- Thread starter rham
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Miami78
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The 8's will make the cylinder's run 70-100 degrees hotter and make it run leaner...if you are already running lean you will want the cooler plugs. I had a 9 in my rear cylinder and an 8 in my front after I pulled my plugs and saw my front was running richer (plug was black) than my rear. Not sure how that helps at high alt though...
buelladdicted
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The heat range of spark plugs ,does not change the tune of your bike.The heat range is that of temperature of the plug itself .If a motor is running rich,a hotter plug will take longer to load up as it can burn the carbon off quicker,if your motor is running lean,a hotter plug has the potential to get too hot and cause preignition .The thing to remember is the plug is responding to the combustion temp. ,not the other way around.There shouldnt be much advantage to the hotter plug unless the engine is running so rich that colder ones are loading up.
Miami78
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What buelladdicted said...I got my info bassackwards. My front was running rich, hotter plug was put in cause the colder one was fouling and the hotter one would burn off deposits better.
Reading up on high alt riding...tip temp on the plugs will drop due to a decrease in air pressure, which could cause fouling. The hotter plugs will help prevent this.
Reading up on high alt riding...tip temp on the plugs will drop due to a decrease in air pressure, which could cause fouling. The hotter plugs will help prevent this.
Thanks for everyone's help. I just took my plugs back and traded them for the nines because the service manual calls for them and I think the altitude thing could probably just be a tuning fix rather than modifying plug type. Maybe a k&n filter would allow better air flow and such. Just doing my 10,000 mile tuneup and so far I've changed all of the fluids and spark plugs. Will work on clutch tuning etc... later.
