What heat range of spark plug are any of you using on a Raptor with 11:1 piston? I know on cars we use a colder plug with higher compression. Right now it has the stock style plug. If any replies please give the NGK # .

Thanks

 

Come on , you guys are pro's at this stuff by now.[img]i/expressions/face-icon-small-wink.gif[/img]

 

For a little ATV engine, 11:1 isn't really that high. I wouldn't go any hotter than a 7 (NGK) or cooler than a 9. I would go with probably 8 or 9.

 

Thanks ALKy, It's a stock plug that has #9 in the part # so I'll assume that it all good.I thought the higher the number the hotter the plug and vice versa, correct me if Im wrong.

 

The lower the number the hotter the plug. It has to do with the length and diameter of the electrode and how long it take the spark to travel through it. If stock is a 9, that is what I would run. An 8 should also run fine.