Originally Posted by johninlv
I have used K&N Air Filters on dirt bikes and four-wheel drive trucks since they first came out, serviced them religiously.
A new bore and piston every year.
.010 cylinder bore wall taper on my Turbo Diesel pickup after 100,000 miles.
These vehicles used only premium lubricants that were available at the time.
In later years I found out thru oil analysis that high levels of silica could be directly traced to the quality of your air filter.
My last desert bike was a CanAm 250 with a twin air filter that never needed a new bore or piston. I donít think the fraction of a Horsepower is worth the cost of the Baja Bore job. The bikes I have now I want to last, if I lust for more power I will go to a big bore kit.
This. It is a well known fact they let more dirt by. For street only use in low dust, it might be ok.