Im gonna put a FMF Fatty Pipe and a Power Core Silencer, i ride on the creeks and on the trails, what jet do i need to go to? Some told a 250 others have told me all the way up to a 270! Also, whenever I put the pipe on, after i ride a mile or two at 1/2 to 3/4 throttle , whenever i pull the spark plug, how do I tell if its runnin lean or rich?

 

http://www.blastercentral.com/NoFram...ting_101.shtml

 

I don't recall what the stock main jet is for a Blaster, but with just a pipe I would recommend that you get the next two sizes fatter than stock. Install the fatter of the two & do a test & plug read.
After running at 3/4 to full throttle for a mile in whatever gear you like, stop & pull the plug. A correct fuel mix is indicated by a light tan or brown color on the electrode and insulator. A dark or black color shows a rich mix & you can drop down to the lower of the two jets that you bought. Re-test to be sure you're on the money. Your jet needle should be in the 3rd position before doing any of this. The reason I suggested going up two sizes is because it is always best to err on the size of rich than lean, as a rich condition won't damage the engine. Maybe a fouled plug is the only possibility. By the way, a lean mix is indicated by a gray or light colored electrode & insulator. If you follow the above steps, I'm sure you won't see that color on the plug.

 

Stock Blaster jet is 230. I would go to a 250 jet, that what i put on when I stuck on ym LRD.

 

I also installed a FMF Fatty Pipe and a Power Core Silencer along with a K&N Air Filter, but am also lost in the jetting area. I am at sea level, what is standard jetting for this situation?