The series of photos below shows a sad case where dirt has found its way into the engine and wreaked havoc. The photos are all from the KX250F I bought on the cheap with the sole intention of rebuilding the engine and documenting the process for my book, The Four Stroke Dirt Bike Engine Building Handbook. Honestly, I couldn’t have bought a better bike for the project, nearly everything on the bike was worn out or screwed up from the previous owner.
Here is how the air filter and airbox looked prior to disassembly.
This photo of the compression ring doesn’t do the situation justice. Some of the dirt was actually removed from the ring as I handled it.
I hope you enjoyed this brief write up on the damage that can result from ingesting dirt, whether from abnormal circumstances such as dropping a running engine into a mud hole or simply neglecting to take care of the air filter when running the engine in dusty conditions. In my next post I’ll show you how to care for and install your filters so these problems don’t happen to you!
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The Four Stroke Dirt Bike Engine Building Handbook is the most comprehensive guide for dirt bike engine building available, whether you are working at home or as a professional in a shop. The process of building four-strokes to race engine quality is explained in-depth in this thoroughly illustrated handbook.
Containing 250 full color pictures, 300 pages of step-by-step instruction, and detailed technical knowledge that can be applied to any make and model, The Four Stroke Dirt Bike Engine Building Handbook is a trusted guide for any expert or beginner.