FX-1 Plug change for Pro-Tec Girdled Head w/ 37 cc Domes

[swapmeet]

I was at the local Yamaha dealer today and out of curiosity, I asked what Plug was reccomended for my ski.

He came back with NGK B8ES

Currently it has BR8HS, thats what was in it when i bought it. On my old ski I ran BR8ES.

Apparently the R has a resistor, and the difference between the HS and the ES is how long the threads are.

I mentioned that it has an aftermarket head and he said he couldn't make a reccomendation because higher compression could make a difference.

For the sake of being through, although I don't think its important, heres what i'm running it in.
701 61X
SBN44
Aforementioned head (37cc domes)
GroupK porting (Hammer Porting)
B-Pipe
MSD Enhancer.

Anyone have a reccomendation? Or does it even matter?

 

[Freakrider]

I was at the local Yamaha dealer today and out of curiosity, I asked what Plug was reccomended for my ski.

He came back with NGK B8ES

Currently it has BR8HS, thats what was in it when i bought it. On my old ski I ran BR8ES.

Apparently the R has a resistor, and the difference between the HS and the ES is how long the threads are.

I mentioned that it has an aftermarket head and he said he couldn't make a reccomendation because higher compression could make a difference.

For the sake of being through, although I don't think its important, heres what i'm running it in.
701 61X
SBN44
Aforementioned head (37cc domes)
GroupK porting (Hammer Porting)
B-Pipe
MSD Enhancer.

Anyone have a reccomendation? Or does it even matter?

NGK B8ES for aftermarket head with extended threads/thickness...you sure don't want to run HS plugs (will lower compression a bit and not reach into the combustion chamber enough).
that's what Ive been running on a well built limited...

ES= extended shaft (most aftermarket heads)
HS= half shaft (stock head thickness)

 

[swapmeet]

Cool, what about the resistor? Does it make a difference? I'll pick up the B8ES tomorrow, thanks for ur help.