I have a 2012 250SX and am having some issues with the top end. Basically they have only been lasting me 5 hours or so. I am on my 4th top end now. After the 2nd time it went, I switched to the 300 kit but still getting the same results. I have noticed that pretty much every time I change my air filter I have a noticeable amount of dirt in the air box. The main tracks I ride on are sand but I take 4 air filters to the track with me and change after almost every moto, which I have never had to do on any other bike (I rode CRF450s for about 4 years before I switched). I even switched to a Loudmouth air intake but still get dirt in the air box. I love the bike but the lack of reliability has me at the end of the line with it. I shouldn't have had to spend the amount of money that I have on this bike for the amount of riding I have done.
Has anyone else had any issues like this?
First off, welcoem to the forum! Secondly, I completely understand how frsutrated you must be and you're completely right, this is ridiculous, but stick with the smart dudes on here, me not included, and it'll get fixed.
What was the reason for swapping out a piston at 5 hours? You should get ten times that out of a well tuned 250. Have you got pictures of the old pistons? Also if you could post up a picture of your sparkplug's action end, that would speed the process too. AS for the dirt in the airboot, is the 2012 250sx equipped with the no tools air box cover? Pretty sure it was introduced in 2011. Make sure that is properly clipped in because I've found that mine (2013 250SX) can look and feel like its clipped in but the bottom clip is off. Also, have you changed the jetting? Have you noticed any odd noises coming from the motor?
Again, bear with it and it'll get solved one way or another. The air boot problem and piston problem are possibly two separate problems.