What spark plugs should I be using?

[JROCK]

According to that link they do extend into the combustion chamber more then the stock plugs. This gives a little higher compression ratio but also has the chance of carbon build up on the threads. If not taken out regularly not sure how long that is, it could damage the threads when taking the plug out. What i got from that link is that the 9's and 10's make about the same HP!

 

[BlueBlood]

I started my Attak for the first time this season a few days ago, and it ran like crap. I took out my CR plugs and put the stockers back in and it ran fine. Never fouled a plug on any of my four strokes before, must have been something with the first start this year.

 

[Srxspec]

The threads do not stick into the combustion chamger/cylinder head any further than the stock CR9EB spark plugs!

CR9EB specs:
10mm Thread
19mm (3/4") Reach
5/8" (16mm) Hex Size
Gasket Seat
Resistor
Solid Terminal
.032" (0.8mm) Gap

CR10EK Specs:
Multi-Ground Plug
10mm Thread
19mm (3/4") Reach
5/8" (16mm) Hex Size
Gasket Seat
Resistor
Projected Tip
Stud Terminal
Dual Ground Electrodes
.027" (0.7mm) Gap

They do have a projected tip which sticks into the combustion chamber further, but no part of the thread surface sticks any further into the combustion chamber.

RX-1: CR10EK
Apex: CR10EK
FX Nytro: CR10EK
RS Vector: CR9EK (they came with a heat range 8 stock)

 

[Blue Dave]

Thanks Allen! That gives me one less thing to worry about. LOL