I've got an 07 suzuki drz400s, in the common 'rejetting' process like everyone else. K, they say it's too lean stock from factory even with the stock muffler and restrictive airbox. But yet if you've got an aftermarket pipe and 3x3 mod, they say the stock 142.5 main jet will work fine. I don't get that. It should be upgraded to like a 150 or somethin shouldn't it? Please help. Thanks!