Hot vs cold spark plugs

This isn't a yz question but I'm sure you guys can still answer it. How does the temp of a spark plug affect the running of a 2smoke motor? I have EZ Go golf cart that I've lifted and put quad tires on and run around the desert in. I'm asking because it's a 250 2smoke and when I got it it didn't run so I rebuilt it put a plug in out of my old KX250. It has alwats run great but I've had the same plug in for a long time and I think it's time to replace it. I got the numbers for the plug that is supposed to be in it but they have a cold and a hot option. How will these 2 plugs affect the engine? I've never had a problem with it fouling plugs and would like to keep it that way as long as possible. Thanks,



When in doubt, GAS IT!

what is in it and what is SUPPOSED to be in it?

what color is the plug, burn wise?


'99 WZ with all YZ mods, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank and IMS seat.

It's been running for about a year on a spare plug for my old KX250. It's jet black. I'm at work so I can't tell you what is exactly in it but I think it was a NGK B8ES I looked online at some golf cart places and they say it should be a NGK BP6HS for cold or a BP4HS for hot. I run it in SoCal deserts mostly at night as a drunk toy when it's 40-60 degrees. Bikes don't make good drunk toys but golf carts do!! I also would never just throw a random plug in my bike but hey, it was a free golf cart and it runs great on this plug. I'm just curious how it would run on the right plug!!


When in doubt, GAS IT!

[This message has been edited by sirhk100 (edited 03-15-2001).]

Waaaaay too rich right now. As the number goes down, the heat goes UP. 4 is hotter than the 6. I would think your KX had a B8EV. The standard plug should be a B9EV. I have always run the B8EV's in 2 YZ250's, a

YZ465 and my CR250 Honda, due to humidity levels east of the Mississippi.

Well if it has been running over a year with that KX plug... then it can't be all bad.

But if the KX plug is an 8... and they recommend either a 4 or a 6... then I would certainly stick with a 6... or maybe a 7.

Wow... 2 stroke golf cart advice on the WR 4 stroke bike forum!

For what its worth... some guys had a Yamaha golf cart on my lake every week this winter and would ride all over on it.. with as many as 5 people in it.... just having fun.


all plugs except CHAMPION! they go the other way!


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