Hello
What size jets would I need to use,,,, living in tenn with a K&N airfilter and a slip on pure polaris pipe on a 2005 Predator 500 . Need to know for a friend sorry about the last post

Thanks
Joe

 

With the same set up, plus my head pipe, i went with a 155 main and a 47.5 pilot. This produced a very nice, clean burn with a smooth transition from the pilot to full main, (whereas my 155 with the stock 45 pilot produced a little bobble and very slight hesitation by comparison) Without the head pipe, a 152.5main might be the hook up, if it's not too lean. Lots of people like to run their jetting far too rich if you ask me, i like it just slightly rich. Ideally, you're looking for a paper-bag brown spark plug, with the 155 and the 47.5 mine is very slightly darker than this, so i'm just rich enough to know i'm not hurting the engine. I suggest you start w/ a 152.5 main and maybe go up to a 155. Also, as it gets cooler, you can go bigger on the jet because air is much more dense in the winter time. a 155 or 157.5 might be the ticket in the winter months for optimum horsepower, but doing this is not necessary on a four-stroke, just saying it's possible. Hope that helps.