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Air filter maintenance and cleaning

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It's hard to find any definitive comparisons, but as an example this is found on a google search. It is indicative of the amount of contaminant which passes a typical air filter. My experience of air filter testing is that a decent modern production type filter should capture comfortably over 95% and more like 98% of Arizona fine dust.

Just sayin'


You may consider the amount of dust passing through the air filter doesn't really matter.

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You may consider the amount of dust passing through the air filter doesn't really matter.




If that is you, read on..


Interesting subject air filters. When we first started tuning the FJ Yamahas we enjoyed good power but suffered an infuriating (and bloody expensive) rash of inlet valve failures.


We use the titanium valves from an R1  and they would burn out in a totally random sequence. We threw everything (including a small fortune) into it and got nowhere. At the end of every meeting at least one (of six) bike and frequently more would burn somewhere between one and four valves. 


Four bikes run Mikuni flat slides and two Keihein, none had air filters. The boss had an epiphany driving in one morning and thought the random failures could be minute shit particles (technical term) getting trapped between the valves and the seats and stopping the valves from seating (and, as a direct result, overheating and burning).


I was sceptical. Truthfully, we all were. But we were so desperate we would have tried anything. Air filters were acquired and fitted to our mount for the Classic TT. It was inconclusive because the rider (a man with impeccable mountain course credentials) thought they might be restricting performance and reached down, pulled them off and threw them away at 160 mph down the Sulby Straight. It was, you may not be surprised to learn, the last time he rode for us..


Bottom line? All our bikes now have filters and not one single valve has failed since. Important things, filters.




Edited by Tex
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