different spark plugs for the 400ex?

[fish22]

I've done some searching around and was wondering about different plugs and their effect on the 400ex?

seems like i read something about different plugs running at different temps or somthing....

[honda400ex2003]

they are different heat range plugs

the dpr8z runs hotter than the dpr9z

the 9z is for extended high speed high rpm runs most of the time and would be required for a colder running tipped plug.

99% of the people with a 400 will never need a 9z, i dont think i have actually found anyone that runs one all the time.

http://en.wikipedia.org/wiki/Spark_plug

thats a good link, go down a bit to heat range and it will fill you in on how they work and what they actually do.

steve

[fearlessfred]

because i ride the sand dunes and do run wide open all the time i allways run one step colder in all my bikes, but i dont ride a 400ex

[fish22]

ok, i was just curious because the other night it was late and i was working on my quad and the plug was fouled out.
I didnt have a spare, so i grabbed my honda recon 250 spare and it was the same size so i put it in the 400 and it fired right up.....
It is a DPR8EA-9.

whats the difference in a DPR8EA-9 and the 400's DPR8Z?

[NacsMXer]

Originally posted by fish22
ok, i was just curious because the other night it was late and i was working on my quad and the plug was fouled out.
I didnt have a spare, so i grabbed my honda recon 250 spare and it was the same size so i put it in the 400 and it fired right up.....
It is a DPR8EA-9.

whats the difference in a DPR8EA-9 and the 400's DPR8Z?

The difference is the EA plug is 2mm shorter in length in the threaded section than the DPR8Z. Some EX's came from the factory with that plug and it doesn't really affect how the engine runs badly.

If you really want to run a nice spark plug, i'm a huge fan of the iridium spark plugs. The DPR8EIX-9 is the NGK iridium equivalent of the DPR8Z, but it is the same 2mm shorter in length like the EA plug. If you wanted to run a one step colder iridium plug, you would want the NGK DPR9EIX-9 (DPR9Z iridium equivalent). I run the Denso version of that plug and it is awesome. I found a noticeable increase in throttle response and the plugs are a lot more resistant to fouling than standard copper NGK's.

[NacsMXer]

Here's a copper NGK DPR9Z vs the Denso IX27B I run (same plug as NGK DPR9EIX-9). Notice the different electrode tip on the iridium plug, it creates a much more concentrated precise spark.

http://img36.imageshack.us/img36/6858/dsc0004mo.jpg (http://imageshack.us/photo/my-images/36/dsc0004mo.jpg/)