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K&N Oil Filter # KN-145

KN-145 Product Specifications.

  • Product Style: Oil Filters.
  • Height: 2.331 in (59 mm).Outside Diameter: 2.165 in (55 mm).
  • PSI Relief Valve: 9.43 .
  • Anti Drain Back Valve: No.
  • Style: Cartridge.
  • Weight: 0.2 lb (0.1 kg).
  • Product Box Length: 2.25 in (57 mm).
  • Product Box Width: 2.25 in (57 mm).
  • Product Box Height: 2.5 in (64 mm).

Filter Installation:

  • Note: I bet you wondering why I am going to recommend you taking a look at the Yamaha Shop Service Manual oil change section before you do your oil change? I have saw too many guys do oil changes and strip the drain plug or strip the bolts in your oil filter cover because they torqued the bolts too tight, causing an unsightly oil leak under your precious atv. So do yourself a favor and read before your machine bleeds on the ground because of you.
  • Get a pan and stick it under your atv where your drain plug is and remove the drain plug, and let the oil thoroughly drain out before you put the plug back in. I usually run my machine for a few minutes to get the oil hot, and it seems to drain better.
  • Make sure your drain pan is under the Oil Filter Cover, listed in picture # 2, and remove your oil filter cover and old filter from the atv.
  • Insert the new K&N oil filter shown in picture # 3 into your atv and reattach your oil filter cover, torquing the bolts to spec, per your shop manual.
  • Make sure your drain plug is put back in place and torqued to spec.
  • Put the recommended amount of oil in your atv, and start it up, checking for leaks.
  • Shut it off, let it set a bit, then check your oil to make sure you have the correct amount of oil in your atv.
  • Final check for oil leaks, and you are good to go.
  • Note: We use Motorex ATV-Quad Racing 4T 10w50 100% Synthetic Oil # 171-465-400 shown in picture # 4, in all of our atv's now. We find this oil gives us easier starting, less warm up times, better gas mileage, and seat of the pants better performance.

My Impressions:


K&N filters are designed for use with synthetic oils.

Meets QS9000 specs.

Made with synthetic-blend filter media for better filtering efficiency & protection.



Bottom Line:

I have been using K&N oil filters on all my atv's for the past 6 years now and we have never had an engine failure due to a malfunctioned oil filter.

These oil filters do just that, they trap contaminants before they get the critical parts of your engine.

These filters work, and work well to protect your engine, and I highly recommend any K&N product for your vehicle.

Note: These filters do their job, but will not if you don't change your oil on a regular schedule. One thing we always do is change our oil, and clean our air filters after riding in the sand or very dusty trails.

Contact info:

Web Site:


K&N Engineering, Inc.

1455 Citrus St.

Riverside, California 92507



(800) 858-3333 or (951) 826-4000


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