Spark Plug Options

[Bryan468]

I’m not sure if there’s a spark plug thread started yet but if not here it is.

Recently I had the plugs out of the bike and rather than just order stock replacements and be done with it I decided to order a couple different plugs.

The reason I did this is because I felt that the stock plugs are a bit overpriced and I wanted to see if I could find a plug that might work better for us that want to push the envelope or run more extreme setup that may benefit from an even colder plug.

One set didn’t work because the top cap on the plug was not removable. Trust me I made sure it’s not removable.. I twisted the center right out of the plug! The set that did work is also the plug that’s used in the H2.

The following plugs will work in our bikes.

Oem H2 SX plugs: NGK SILMAR9E9 $23-$30
Oem H2 plugs: NGK SILMAR9B9 $12-$17

When I checked the gap on the stock plugs I got .032” and the gap on the NGK SILMAR9B9 plugs was also .032” out of the box. I chose to drop the gap to .025” because I plan to start working on a water meth setup soon and I think that might be a little wide for water/meth.

Here’s a picture of the 3 plugs side by side. The tip on the oem H2 SX plug is extended .060” farther than the oem H2 plug. The NGK SILMAR9B9 should run colder since the tip is recessed. I confirmed this with reputable engine builder in my area. The NGK SILMAR9A9S is the plug that didn’t work.

[JonTheChron]

Awesome post. I always wondered about the differences.

[Prof J]

I’m not sure if there’s a spark plug thread started yet but if not here it is.

Recently I had the plugs out of the bike and rather than just order stock replacements and be done with it I decided to order a couple different plugs.

The reason I did this is because I felt that the stock plugs are a bit overpriced and I wanted to see if I could find a plug that might work better for us that want to push the envelope or run more extreme setup that may benefit from an even colder plug.

One set didn’t work because the top cap on the plug was not removable. Trust me I made sure it’s not removable.. I twisted the center right out of the plug! The set that did work is also the plug that’s used in the H2.

The following plugs will work in our bikes.

Oem H2 SX plugs: NGK SILMAR9E9 $23-$30
Oem H2 plugs: NGK SILMAR9B9 $12-$17

When I checked the gap on the stock plugs I got .032” and the gap on the NGK SILMAR9B9 plugs was also .032” out of the box. I chose to drop the gap to .025” because I plan to start working on a water meth setup soon and I think that might be a little wide for water/meth.

Here’s a picture of the 3 plugs side by side. The tip on the oem H2 SX plug is extended .060” farther than the oem H2 plug. The NGK SILMAR9B9 should run colder since the tip is recessed. I confirmed this with reputable engine builder in my area. The NGK SILMAR9A9S is the plug that didn’t work.

Bryan, it's been some time now since you plug purchase. What have you discovered about running the NGK SILMAR9B9 plugs?

[Bryan468]

Not a lot to say. I installed them and forgot about them. No issues to speak of.

I think installing the h2 plugs should be highly considered. I’ve seen a few cases where people have melted the electrodes off the stock plugs. In one case the bike was completely stock.

[Vex]

Bryan, to be clear, you installed the 9B9's from a regular H2, and have been running them flawlessly?

[Bryan468]

Bryan, to be clear, you installed the 9B9's from a regular H2, and have been running them flawlessly?

That’s correct.

[Snakes709]

Bryan i wanna bring this thread back to life to ask, any chance you know what the thread pitch is on the plugs? I gotta swap mine over the winter and while im in there i wanna do a compression check just for the hell of it. I dont have the correct attachment so i need to order one once i figure out the pitch of the threads.

[Bryan468]

Bryan i wanna bring this thread back to life to ask, any chance you know what the thread pitch is on the plugs? I gotta swap mine over the winter and while im in there i wanna do a compression check just for the hell of it. I dont have the correct attachment so i need to order one once i figure out the pitch of the threads.

The thread pitch is M10-1.0

[Snakes709]

Awesome, thank you.

[Vex]

Just wanted to chime in on this. I've had regular H2 plugs in for a while (6-10k mi), and they've been stellar.

When we pulled the original plugs, one of them was partially melted, and the rest didn't look great. This was before S1, so just sprint, filter, exhaust, and David's tune (at the time). I highly suggest swapping them out too if y'all get a chance.