Got the plugs in the mail yesterday ( [ame="http://www.amazon.com/gp/product/B000CSGWZM/ref=oh_o00_s00_i00_details"]Amazon.com: NGK (3521) CR9EIX IX Iridium Spark Plug, Pack of 1: Automotive[/ame] ) $7.40 a piece, free shipping for four.
Checked the gaps, 3 were .031", #4 was .030".
Just finished swapping them out (10,000 miles on the bike).
Some comments,
I found the problems most guys having removing the plug caps is rectified by gently prying up on the rubber cap that seals the plastic spark plug lead to the valve cover. I used a thin long screwdriver, wrapped in duct tape to prevent any scratching. Once the seal was broke, the caps came off much easier.. An air compressor was used to blow out any crap in each cavern..
When later re-assembling, I put just a little bit of di-lectric grease on the inside of the valve cover so the rubber doesn't stick, is more water proof and assembles much easier.
I used the tool kit socket but also used a
combo box end 14mm wrench that rachets (Craftsman). Much easier, especially when reaching in to #2and #3 plugs. One click at a time due to the tightness..
For the new plug installation, I used a short piece of hose (about 5") that fit snuggly on the new plugs and feed that down into the hole and threaded it by hand.
Yamaha's manual calls for 13' lbs of torque, the spark plug box 1/2 turn past snug, NGK's website for a 10 mm thread 7.2' to 8.7 ' lbs of torque.
I was able to use the toolkit socket, with a short 6 point 14mm socket and an
inch pound torqe wrench. I was able to reach all the plugs (with the radiator dropped per the manual) and torque to 7.2' (felt very tight).
Performance:
I had the original plugs in the bike and regularly use Seafoam and K100
(
K100 Fuel Treatment : Fuel Additive, Fuel Saver ). The original plugs looked very good and the bike runs great.
With that said, I really cannot feel any difference between the Iridiums and the stock plugs short of a slightly smoother idle.. I suspect because the originals were in such good shape. A test ride felt the same, acceleration about the same and no noticable difference... I'll keep an eye on gas mileage..
In either case, a racheting 14mm box wrench is a big help with a short piece of hose (I was afraid of dropping the new plug out of the stock plug socket. The hose is much easier to manipulate with the plug into the hole).
Maybe took an hour, tops... Hope this helps...
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