No lid, No spark arrestor= gains

[BIGRED400]

after experimenting with disc, airbox mods, jetting , ...........It seems to have the most pull with my E-series without spark arrestor, no lid with 165 main.......K&N with outerwears plan on a 416 11-1 with hotcams -2 next...anyone running this???

[Silverfox@C&DRacing]

My set up is pretty close.. 416, hotcam stg 2 no lid, k&N, sparks with the spark arrestor (disc style) I only use the spark arrestor once in a while. this is a good set up!! we just did this to a local customers bike and he said that he won't ever ride a stock 400 again..