Can anyone recomend a great sparkplug?  is the hype about split-fire true?  or any other brand?

what do we use?  DPR8EA-9 does that sound right?

Quote from: klimberwhat do we use?  DPR8EA-9 does that sound right?

I can't comment on "super plugs", but you're right about the standard plug.  Here is a link to the GS500-specific page on the Motorcycle Accessory Warehouse site.  I use the info at the top for a quick reference on some of the more obvious OEM parts & sizes.

I would use the stock recommended  NGK spark plug. NGK makes good plugs and you know it wont mess anything up. You would be surprised what having the wrong spark plug can to. The race team I help had the wrong plugs in there $60,000 410 sprint car engine and within about 3 or 4 laps it had burned holes in three of the eight pistons, not good. Im not saying this will happen in the GS but I have seen quite a few NGk plugs used in sleds, motorcycles, and racecars and I think there a deceant plug, although they might not be the best.

NGK are very good plugs and I prefer them personally. I've used a Splitfire in my 250 single once to see if it would make a difference. At first I thought it did, until the next time I replaced it with an NGK and felt no diff. But also because I couldn't justify the $8, or the fact that something flaked off the anode. But, it might have been due to the fact that Splitfire claims to increase power by 1 to 5 percent and well a 1 to 5% increase on 22hp is...not much. Multiply 0 by 5% equals...0. So, I've been very happy with NGK. Now, with the powah of the 500, which is what, 40hp? 40hp x .05 = a 42hp potential(!). Remember I said potential, as Splitfire claims a  1 to 5% increase.
I'll betchu it wont make a difference.