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Discussion Starter #1
Any one doing it? My bike sat for a good while and I've always felt like after all my mods I lost a lot of gas mileage and keep feeling like I'm running rich. I can smell it but I do still get some backfiring when slowing down. I've played with my tuning over and over, have yet to actually check my spark plugs because of course I didn't get the tool kit like most did with the spark plug puller. But considering I have the Cobra pro hp 2-into-1 and the kuraykn hypercharger pro r which are supposedly the two best mods for hp gains (so said at the time of purchase over a year ago) I'm thinking of going a step colder. Any thoughts, opinions or experiences?
 

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I was just thinking today when I checked my plugs they are a tad on the hot side,other than that they look fine.This is after taking out the secondary throttle plates.So suppose you could go colder.
 

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Discussion Starter #3
So found the correct plugs and gap size if anyone else is interested (I live by NGK plugs)
CPR8EA-9 gap 0.36 or 8-9mm
 

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Discussion Starter #5
An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

taken from the NGK website here http://www.ngk.com/faqmain.asp
 

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An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

taken from the NGK website here http://www.ngk.com/faqmain.asp
So in your case you think a colder plug will work better? This is without looking at the plugs that are in there now? Just asking why you think, in your case, it's necessary. Many people on this forum have made similar modifications so I think this is important.
 

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Discussion Starter #7
Because I'm still running my factory plugs and I ran the bike on so many different setting with my pc3 if my plugs aren't fouled with all their back firing and the gas I can smell I'll be extremely surprised.
 

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Because I'm still running my factory plugs and I ran the bike on so many different setting with my pc3 if my plugs aren't fouled with all their back firing and the gas I can smell I'll be extremely surprised.
Roger that, but and don't take me wrong, replacing the plugs with colder ones will just hasten the fouling if that's what your bike is prone to do. If the stock heat range is not right and your plugs are fouling then a hotter plug is what you need. You fail to mention how many miles on the factory plugs. I think before you post that we should consider colder plugs because we've debaffled or installed a free flow air filter, you need to analyze what is presently in your ride.
 

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Discussion Starter #9 (Edited)
This is simply for me not what I recommend for you or anyone else running colder plugs after a lot of mods like that is usually recommended. I run a step colder in my far swell and only run 91 octane due to chipping and other mods. If I was weakening my bike some how then I'd run a step hotter but that can cause other issues. Running colder plugs could cause them to foul sooner but won't cause any serious engine issues. Another thing is I don't have just debaffled pipes or a free flow airfilter reread the first post.
 

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By the nature of opening the intake right under your nose you will occassionally smell fuel. Colder plugs and higher octane fuel will not eliminate it; cooler cylinder temps and fuel that's harder to ignite (vs 87 octane) will produce opposite results. You can't compare the 900's very modest performance to an engine with a turbo, super charger. NO2 or any other performance modification. In the example above the reason for the colder plugs is to minimize the potential for dentonation; this is not an issue for 900. You're way over estimating or reading too much propoganda on the performance gains of the hyper. Best bet is to leave the stock plugs alone, run 87 octane and keep tweaking the fuel map. And on some 900's the popping may never be completely eliminated because it's an open loop injected system.
 
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