Here's the dope, it's a 93 250 trailboss 4x4. The machine had a complete rebuild all the way down to the crank bearings before last winter. In the quest for more power I had the head milled, .020 during the summer and installed. At this point I had a ping on 87 octane. Started running 93 octane all was good. Got 4in. of snow last night, went out plowing and it seemed the ping came back on low rpm's. Under full throttle and more load I couldn't here the ping. It's got a k&n filter, one size over main jet, and the clutch spring has been replaced for higher engagement. Maybe it's just the load on low rpm's, and it can't be fixed.

 

You risk piston damage riding it like that, with the colder temps your probably lean. go larger on the main jet and turn the airscrew in a turn and see what that does. You may also have to raise the needle to richen the mid range...

 

Yep it sounds like you are lean. Do a plug check at idle and midrange after it is warmed up. You should be brown color. If you are gray or white then you need to richen it up.

 

Thanks guys, had a notion about a lean condition. Needed some confirmation. That machine pushes a 5 ft. plow around really well, and being physically small I can get into alot of tight spots to plow.

 

5 ft. plow? Something that big should be on the front of a Dodge diesel truck.

 

5 feet = 60 inches

A 60" blade can be used on a 500cc or larger atv. My Vinson handles it quite well.

 

Upped the main jet from 150 to 160. Thanks guys
Doc

 

not enough octane for the compression you have now, IMO.