Harley-Davidson Oil Filter Chart
Real AMSOIL, OEM, Fram, WIX, and K&N part numbers by engine, plus why Harley’s “5-micron” rating and AMSOIL’s efficiency rating aren’t actually measured the same way. US & Canada, 2026.
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By Alan Williams, AMSOIL Direct Jobber #1243776 · Tomball, TX · 225-441-6397
On This Page
- Quick answer: which filter fits your Harley
- Oil filter cross-reference chart
- Why “5-micron” and “98.7% efficient” aren’t the same scale
- Fluid cross-reference: engine, transmission & primary
- Filter dimensions and the wrench you’ll need
- How often to change it
- The Preferred Customer program
- Alan’s take
- Frequently asked questions
Quick Answer
Most Harley-Davidson motorcycles, all Evolution, Twin Cam, and Milwaukee-Eight engines including Sportster, use the same filter footprint: AMSOIL’s equivalent is the EaOM134 (or chrome EaOM134C), matching Harley’s own OEM Super Premium filter, part number 63731-99A. It’s a 3/4″-16 thread, spin-on filter, roughly 3.4″ tall and 2.97″ in diameter.
Worth knowing up front: Harley’s own filter spec has changed across engine generations, older Evolution-era shop manuals commonly called for a 30 to 40-micron filter, while current Twin Cam and Milwaukee-Eight models specify a tighter 5-micron nominal filter. Using the wrong-generation filter isn’t just a minor mismatch, it’s the wrong part for your engine’s oil pump and bypass valve design. Always confirm against your specific model year below.
The Actual Cross-Reference
Oil Filter Cross-Reference Chart
For Twin Cam, Evolution Big Twin, Sportster, and Milwaukee-Eight models using the common 3/4″-16 spin-on filter:
| Brand | Part Number |
|---|---|
| AMSOIL Ea Motorcycle Oil Filter (black) | EaOM134 |
| AMSOIL Ea Motorcycle Oil Filter (chrome) | EaOM134C |
| Harley-Davidson OEM (black) | 63731-99A |
| Fram | PH6022 or PH6065A |
| WIX | 51348 |
| K&N | KN-171B |
| HiFloFiltro | HF171 (or chrome HF171RC) |
| Mobil 1 | M1-102 |
| Purolator | PL10241 / PL25230 |
| Bosch | 3330 |
This cross-reference matches the common Twin Cam/Evolution Big Twin/Sportster/Milwaukee-Eight thread and dimension. Newer Milwaukee-Eight model years have seen some aftermarket brands (WIX, Fram) lag behind with a listed part, per rider reports, so if a lookup tool shows no match for a very recent model year, check directly with AMSOIL or your dealer rather than assuming no filter exists.
The Part Nobody Explains
Why “5-Micron” and “98.7% Efficient” Aren’t Comparable
Harley-Davidson rates its Super Premium filter using a nominal micron rating. AMSOIL rates its filters using an absolute (efficiency) rating. These are genuinely different measurement scales, and comparing the raw numbers between them is misleading:
- Nominal rating (Harley’s “5-micron” claim) generally means the filter is only around 50% efficient at stopping particles that size, roughly half still get through. A nominal rating alone says nothing about efficiency unless efficiency is stated alongside it.
- Absolute/efficiency rating (AMSOIL’s approach) states a specific efficiency percentage at a specific particle size. AMSOIL Ea Oil Filters are documented at roughly 98.7% efficient at 15 microns.
The honest takeaway: a “5-micron” nominal filter and a “98.7% at 15 microns” absolute filter can’t be ranked against each other from those numbers alone, they’re not on the same scale. What actually matters is efficiency at a stated particle size, not the smallest micron number on the box. If a filter brand advertises an ultra-low micron number with no efficiency percentage attached, that’s an incomplete claim, not necessarily a better filter.
Related, Not the Same Thing
Fluid Cross-Reference: Engine, Transmission & Primary
Since a filter change usually happens at the same visit as a fluid change, here’s the current AMSOIL part-number match for the fluids themselves:
| Harley-Davidson Part (#) | AMSOIL Equivalent |
|---|---|
| HD Engine Oil (99816-60) | MCS SAE 60 or MCV 20W-50 Engine Oil |
| Screamin’ Eagle Syn 3 (99824-03) | MCV 20W-50 Engine Oil |
| Primary Lube (99887-84) | MCV 20W-50 Engine Oil (or MVP Primary Fluid) |
| Transmission Lube (99892-84) | MVT Synthetic V-Twin Transmission Fluid |
| Sport-Trans Fluid (99896-88) | MCV 20W-50 Engine Oil |
| Type B / Type E Fork Oil (99880-73 / 99884-80) | STM #10 Suspension Fluid |
This table reflects AMSOIL’s current MCV/MVT/MVP product line. If you’ve seen older references to AHR, SVG, or SVO codes elsewhere, those were AMSOIL’s prior-generation product names, superseded by the current lineup shown here. For the full engine-by-engine breakdown with JASO specs and drain intervals, see the Harley Motorcycle Oil Guide.
Fit & Tools
Filter Dimensions and the Wrench You’ll Need
- Thread: 3/4″-16
- Height: approximately 3.4″
- Outer diameter: approximately 2.97″
- Bypass valve: HD’s OEM filter uses roughly an 8 psi relief valve with an anti-drainback valve; confirm your aftermarket choice matches
- Filter wrench: a 76mm wrench (AMSOIL’s own tool is the GA251) fits the EaOM134/134C and most equivalents in this chart
Interval
How Often to Change It
AMSOIL recommends changing the Ea Motorcycle Oil Filter at every oil change, for maximum engine protection. If you’re running AMSOIL synthetic oil at its extended interval, that means the filter and oil come out together on the same schedule, no separate tracking needed. See the full Maintenance & Service Checklist for the complete mileage breakdown.
The Preferred Customer Program
Wholesale Pricing on Filters and Fluids Together
- 25% off retail pricing on every AMSOIL product, every order, all year
- $20 a year (charged in local currency at checkout for Canadian members), no minimum purchases
- Direct from AMSOIL: filters, engine oil, transmission and primary fluid at the same discount
- Ships to both the US and Canada
Sign up once, save 25% on every order after.
$20/year, no minimums, ships to the US & Canada.
Alan’s Take
“I get asked constantly whether a cheaper aftermarket filter is ‘just as good’ as the Harley OEM one, and the honest answer is it depends which number you’re looking at. The micron rating alone doesn’t tell you enough, match the thread, the bypass pressure, and check the efficiency claim, not just the smallest micron number on the label. I run the AMSOIL EaOM134 on my own bike because I trust the efficiency data behind it, not just a marketing number.”
Frequently Asked Questions
What is the AMSOIL equivalent to the Harley-Davidson oil filter?
AMSOIL EaOM134 (black) or EaOM134C (chrome) matches the Harley OEM Super Premium filter, part number 63731-99A, on Evolution, Twin Cam, Sportster, and Milwaukee-Eight models.
Should I use a 5-micron or 30-micron filter on my Harley?
Follow your specific model’s owner’s manual. Older Evolution-era engines were commonly speced for a coarser 30 to 40-micron filter, while current Twin Cam and Milwaukee-Eight models call for a tighter 5-micron nominal filter. Using a filter designed for a different engine generation isn’t automatically an upgrade.
Is a lower micron number always a better filter?
Not by itself. A “5-micron” nominal claim without a stated efficiency percentage doesn’t tell you how effective the filter actually is at that size, it could be as low as roughly 50% efficient. An efficiency rating at a specific micron size, like AMSOIL’s 98.7% at 15 microns, is a more complete and comparable claim.
Can I use a K&N or Fram filter instead of the AMSOIL or OEM filter?
Yes, as long as the thread size, dimensions, and bypass valve pressure match your model’s specification. The cross-reference chart above lists the matching part numbers across several major brands.
How often should I change my Harley’s oil filter?
At every oil change. If you’re running AMSOIL synthetic oil at its extended interval, the filter changes on the same schedule as the oil.
Where can I buy AMSOIL filters at wholesale pricing?
Through the AMSOIL Preferred Customer program: $20 a year for a permanent 25% discount on every order, shipping to both the US and Canada.
Stop Paying Retail for AMSOIL
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Disclaimer: AMSOIL specification data sourced from AMSOIL’s own published product documentation, current as of 2026. Cross-reference part numbers are compiled from manufacturer documentation and long-standing rider-community references and should be independently verified against your specific model year before ordering; filter specifications have varied across Harley-Davidson engine generations. AMSOIL, Harley-Davidson, Fram, WIX, K&N, HiFloFiltro, Mobil 1, Purolator, and Bosch are registered trademarks of their respective owners; this article is not endorsed by or affiliated with Harley-Davidson or any competing filter brand. Lube Oil Sales is an Authorized AMSOIL Independent Dealer (Dealer #1243776). This page contains affiliate links to AMSOIL’s Preferred Customer program. Last updated: July 2026.