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[Midnight Rider]

I figure it's about time to change the plugs in my scoot with the 10K service coming up.  Stock motor, stock wires, Rinehart True Duals, PCIII, and a good tune running A/F ratio of 13.4 to 1 accross the RPM ranges (give or take .2)

Recommended Plugs?  All things being "normal", real life recommended change intervals?

[Fired00d]

Terry,
Don't ask me where I've read it here, but I believe that it is recommended that we stick w/what the MoCo has in/recommended we use for our bikes. I do keep a spare set (guess it's from old carb days) in my saddlebag, but w/EFI I don't think there is the need/problem that occurs w/carbs (fouling) to have to change them more then what the MoCo recommends. [smiley=nixweiss.gif] If memory serves me correctly I think it has been noted that there has been more trouble then not when people have tried different plugs (split/SE/etc) vs stock.

 [smiley=pumpkin.gif]
Ride Safe,
Fired00d
 [smiley=fireman.gif]

[BLM777]

Well Terry, I'll confuse the issue.

[Unbalanced]

Autolite plugs.

[SPIDERMAN]

I like the Screamin Eagle Platinum plugs gapped to the max for a nice fat spark ! I also index em when I'm feeling ambitious.

B B

[grc]

Spark Plugs for Twin Cam Engines
Plug Gap .040"

H-D Standard

[ESJ JESTER]

The OEM plug works.therefore IIABDFI (if it ain't broke,dont fix it) But...Autolite makes a good plug
for me http://www.ngksparkplugs.com/about/index.asp?nav=20000&country=US is what i will try when its time.
Most important thing isnt brand as much as "indexing" the both plugs correctly and equally. This is done with index shims to get plugs to tighten in the position to allow commencement of flame front to start so as to burn mixture from center of cylinder outward and thus downward. In other words if the plug tip of one cylinderfaces the cylinderwall in one cylinder and the center in the other...piston will try to move away from explosion in a lateral way rather than DOWN.. which is the prefered direction.  there is a billet indexing tool avail to check and index the plugs. depending on where the thread cut was started ...plugs will usually come tight in several locations and thus the 3 different thickness "index shims"  Moroso makes the shims.  We would get 15% more top horsepower on the v-8 and v-12's when indexing.  the best sweet spot is found naturally when the heads are off and plug is located for spark path to maximize burn.    just my .02
Gene

[Hoist!]

The OEM plug works.therefore IIABDFI (if it ain't broke,dont fix it) But...Autolite makes a good plug
for me http://www.ngksparkplugs.com/about/index.asp?nav=20000&country=US is what i will try when its time.
Most important thing isnt brand as much as "indexing" the both plugs correctly and equally. This is done with index shims to get plugs to tighten in the position to allow commencement of flame front to start so as to burn mixture from center of cylinder outward and thus downward. In other words if the plug tip of one cylinderfaces the cylinderwall in one cylinder and the center in the other...piston will try to move away from explosion in a lateral way rather than DOWN.. which is the prefered direction.

[Boatman]

I'm queer for NGK so I use their Iridium plus.

[ESJ JESTER]

I whole heartdly agree  split fire's absolutly su#%k bad.  had many vette customers insist on em and every one came back and got ngk's whining about how they spent 7.50 ea for the splits and how they got ripped. I had a old champion plug machine that had a coil and magnifiying window that we checked each plugs actual spark with it. `the difference between a good running engine and a great running engine starts with the ole sparkpins...

[Midnight Rider]

I've always been partial to NGK as well...think I'll give them a try at 10K.

Has anyone actually done a dyno test to see whether indexing towards the intake or exhaust works better on the 103 motor.  If not, it seems like the logical thing to do is just make certain the ground is open to the chamber  and not blocking.

[grc]

I've been planning to try indexing the plugs on my 103, but so far I can't find indexing washers for a 12mm plug.  Moroso makes flat or tapered washers for 14mm plugs.  Anybody got a source?

Jerry

[Midnight Rider]

I've been planning to try indexing the plugs on my 103, but so far I can't find indexing washers for a 12mm plug.

[ESJ JESTER]

thats the purpose of the tool it allows you to go to your fav parts house where your young crotch-rocket counter guy is and together the both of ya carefully open 20-30 plugs and then you buy all those that index the same  i do that and then dont need the washers. it starts with a known plug touqued in the hand held block of aluminum. I will check for the 12mm shims
gene    

[ESJ JESTER]

I have a call into tech support of ngk about the 12mm shims. will post response 8-5 est

gene