Spark Plug

[rd400racer]

I recently picked up a Skorpion racebike. It wasn't running due to bad gas so I cleaned the carb and while I was at it I changed the plug. I did not have a DPR8EA in the shop but I had a DPR9EA, which I put in. The bike fired right up. Can I hurt the engine with this plug?

[comanche91]

I recently picked up a Skorpion racebike. It wasn't running due to bad gas so I cleaned the carb and while I was at it I changed the plug. I did not have a DPR8EA in the shop but I had a DPR9EA, which I put in. The bike fired right up. Can I hurt the engine with this plug?

Unlike most other plugs, on the NGKs the higher the heat range number, the colder the plug. So a 9EA is one range colder than the 8EA. The worst think that could happen is that it may foul up. Pull the plug after a few 100 miles and look at the color. Ideally it should be a tan color, not sooty black (too cold) or white (too hot).

[basser23]

I agree with the 9 being colder,just check it as mentioned..if it is race only,it may just be perfect depending on track length etc.
Bill Jurgenson I think recommends a 7 for street use.....

[rd400racer]

Thank you all for that info. I normally race RD's and RZ's, and I've had occasions where one size wrong with the plug or jet has holed a piston. I bought this bike for my son to do trackdays with, but I think it will see Clubman action in WERA. Just riding it down the street today put a huge smile on my face.

[DAVID THOMPSON]

warning MZ = addiction you have been warned
dave
i am up to 3 now nuff said