Was wondering how hot the engine should run on the jm 125.After installing a K&N filter and a new chain on my sons jm 125 i went to put the chain cover back on and noticed the engine was smoking hot?You could feel the heat.Could this come from the chain being to tight.Could this little filter do this.I do no if you upgrade the exhaust you change jets but on just a filter?

 

anytime you make a change in airflow, you're going to hafta to rejet, doesn't matter if its an airfilter or exhaust

 

Also just put a K&N on my honda 250ex.The intructions say NO rejeting required?

 

replacement k&n's that fit in the stock airbox normally don't require rejetting, but if you removed the stock airbox on your honda and replaced the stock airbox and airfilter with a clamp on k&n then rejetting will be required

 

Did a plug check and it shows white,now what?