How do I know if a custom primary cover will fit my bike?

Fitment is very specific to the year, model, and engine of your motorcycle (e.g., Sportster, Evo Big Twin, Twin Cam). Always use the bike filter on our website and carefully read the product description, which lists the exact models and year ranges the cover is designed for.

Is installing an open primary kit a job I can do myself?

This is an advanced, expert-level installation. It requires precise alignment of the engine and transmission pulleys, proper belt tensioning, and clutch setup. We recommend this job for experienced mechanics only.

Do I have to change my clutch to run an open primary?

Yes, absolutely. Stock Harley-Davidson primaries use a "wet" clutch that runs in oil. An open belt drive must run "dry." Therefore, all open primary kits require you to convert to a dry clutch assembly, which has different friction plates designed to operate without oil.

Motorcycle Primary

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Primary Chain Adjuster Kit - 1965-2000 Harley-Davidson Big Twin Cycle Standard
$70.30

Primary Cover & Inspection Cover Gasket Kit 8-Hole Primary Cover 1970-1982 Harley-Davidson Shovelhead James Gaskets
$68.87

Primary Cover Gasket 1965-1988 Harley-Davidson Big Twin James Gaskets
$24.91

Derby Cover - Chrome - 1970-1998 Harley-Davidson Big Twins Cycle Standard
$31.18

Triumph Unit 650 Primary Cover Bonneville Tiger Trophy OEM 57-1727 British Standard
$190.35

Derby Cover - Chrome - 1999-2018 Harley-Davidson Big Twin/Twin Cam Drag Specialties
$63.81

Primary Gasket for 1963-82 650/750 unit Triumph Motorcycles - Extra Thick OEM #71-7009 British Standard
$16.94

Primary Chain Tensioner for Triumph Motorcycles OEM #70-6283 British Standard
$42.19

#7811-14 Inner Primary Mounting Kit - 1936-1954 Harley-Davidson Knucklehead/Panhead Colony
$26.08

Primary Cover Gasket & Seal Kit 1977-1990 Harley-Davidson XL James Gaskets
$30.70

Primary Chain Tensioner - 2001-2005 Harley-Davidson Dyna 01-06 Softail/Touring Cycle Standard
$70.11

Duplex Primary Chain Triumph OEM #60-0477 Made in Japan British Standard
$54.13

Derby Cover - Wrinkle Black - 1999-2018 Harley-Davidson Big Twin/Twin Cam Drag Specialties
$63.81

Renolds Duplex Primary Chain Triumph OEM #60-0477 Made in UK British Standard
$121.54

3 Hole Chrome Derby Cover for 1970-98 Harley-Davidson Big Twins Replaces OEMs 60668-84A 253952-84T Cycle Standard
$22.42

Primary Chain Adjuster Kit - 1991-2003 Harley-Davidson Sportster XL Cycle Standard
$34.67

#8919-19-P Primary Cover Smooth Allen Kit 1989-2006 Harley-Davidson Softail 1991-2005 Dyna - Chrome Plated Colony
$48.73

#8155-30 Primary Cover Screw Kit 1936-1964 Harley-Davidson Big Twins - Chrome Plated Colony
$30.00

#7812-12 Inner Primary Mounting Kit - 1955-1964 Harley-Davidson Panhead Colony
$29.98

#3045-14 Inner Primary Chain Guard Kit 1936-1954 Harley-Davidson Big Twins - Parkerized Colony
$26.08

#9769-17 Primary Cover Allen Screw Kit 1994-2003 Harley-Davidson XL - Chrome Plated Colony
$24.37

Primary Cover Gasket & Seal Kit 2004-2022 Harley-Davidson XL James Gaskets
$35.61

#3194-1 Harley Primary Drain Plug - Zinc Plated - Big Twin & Softail - 1987-2003 & 1993-2003 Colony
$9.68

Primary Inspection Cover - Polished - 1991-2003 Harley-Davidson Sportster XL Drag Specialties
$29.82

#8917-19 Primary Cover Chrome Acorn Head Screw Kit 1989-2006 Harley-Davidson Softail 1991-2005 Dyna - Chrome Plated Colony
$56.11

#8918-19 Primary Cover Cap Screw Kit 1989-2006 Harley-Davidson Softail 1991-2005 Dyna - Chrome Plated Colony
$56.11

Primary Cover & Inspection Cover Gasket Kit 1984-1986 Harley-Davidson FL/FLH/FX/FXE/FXWG 1984-1988 Softail James Gaskets
$55.23

#9958-19 Primary Cover Mounting Kit Allen 1999-Up Harley-Davidson FLT - Chrome Plated Colony
$49.25

Primary Cover Gasket 1967-1976 Harley-Davidson XL James Gaskets
$6.73

Replacement Primary Inspection Cover Gasket - 2004-2021 Harley-Davidson Sportster XL Cycle Standard
$6.26

#7350-15 Acorn Primary Cover Screw Kit 1971-Up & All 4 Speed Harley-Davidson Big Twins - Chrome Plated Colony
$48.73

#9770-17 Primary Cover Acorn Screw Kit 1994-Up Harley-Davidson XL - Chrome Plated Colony
$43.45

#8785-12 Primary Cover Allen Screw Kit 1971-1976 Harley-Davidson Sportster - Chrome Plated Colony
$19.36

#8919-19 Primary Cover Chrome Allen Head Screw Kit 1989-2006 Harley-Davidson Softail 1991-2005 Dyna - Chrome Plated Colony
$38.59

#8763-20-P Primary Cover Smooth Allen Screw Kit 1980-1984 Shovelhead & Evo 5 speed - Chrome Plated Colony
$37.22

Primary Cover Gasket 1977-1990 Harley-Davidson XL James Gaskets
$8.84

#3537-17 Primary Cover Allen Screw Kit 1971-Up Harley-Davidson Shovelhead & Evolution 4 Speed Colony
$16.34

Primary Chain Adjuster Pad - 1980-1990 Harley-Davidson Sportster XL Cycle Standard
$8.11

#2342-18 Primary Cover Allen Screw Kit 2006-Up Harley-Davidson Dyna - Chrome Plated Colony
$29.78

#9869-24 Inner Primary Mounting Kit 1980-1985 Harley-Davidson FL/FX Colony
$29.54

Primary Cover Gasket 1952-1969 Harley-Davidson XL James Gaskets
$8.87

#8156-30 Primary Cover Screw Kit 1936-1964 Harley-Davidson Big Twins - CAD Plated Colony
$25.00

#2064-14 Primary Cover Phillips Screw Kit 1971-1976 Harley-Davidson Sportster - CAD Plated Colony
$24.20

#2559-1 Primary Cover Filler Cap 1971-1976 Harley-Davidson Sportster Colony
$23.10

#8892-12 Primary Cover Screw Kit 1967-1970 Harley-Davidson XLH 1970 XLCH - Chrome Plated Colony
$23.01

#3193-2 Primary Drain Plug 2004-2006 Harley-Davidson Softail - Zinc Plated Colony
$11.50

#3653-3 Primary Inspection Cover Kit - Black Powdercoat - 1929-1952 Harley-Davidson 45's 1932-1973 Servi-car 1930-1936 VL Colony
$22.50

#9767-15 Primary Cover Allen Screw Kit 1991-1993 Harley-Davidson XL - Chrome Plated Colony
$22.34

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The Heart of the Drivetrain: Motorcycle Primary Drives The primary drive is where your engine's power meets the transmission. Housed behind a cover, the stock system is designed for quiet reliability. But for custom builders, this area is a massiv...

The Heart of the Drivetrain: Motorcycle Primary Drives

The primary drive is where your engine's power meets the transmission. Housed behind a cover, the stock system is designed for quiet reliability. But for custom builders, this area is a massive canvas for style. Upgrading your primary is a high-impact modification, whether you choose a new look with a custom primary cover or go for the radical mechanical beauty of an open belt drive.

The Heart of Your Drivetrain: Why the Primary Matters

The primary drive is far more than just a side cover; it’s the critical link responsible for harnessing your engine’s raw power and delivering it to the transmission. Every component in this system—from the clutch to the chain or belt—is under immense stress. This is why investing in quality here is non-negotiable.

Reliable Power Delivery: This system handles every bit of torque your motor puts out. A worn-out chain, a slipping clutch, or a flexing cover plate can all lead to power loss and poor performance. A solid primary setup ensures that power gets to where it needs to go.
The Visual Anchor of Your Bike: The primary cover is one of the largest visual pieces on your motorcycle. Changing it with a custom primary cover offers the biggest style impact for the least amount of work. Going for an open primary completely redefines the bike, showcasing its mechanical guts.
Defines the Rider's Experience: The primary system dictates how your clutch feels at the lever and the sounds your bike makes at idle. A stock wet primary is smooth and quiet. An open primary with a dry clutch is aggressive and loud, offering a direct, mechanical connection to the ride.
Crucial Fitment for a Long Life: Because this system connects the engine and transmission, proper alignment is everything. Whether you're installing a new Harley Evo primary cover or a full Sportster open primary kit, a perfect fit prevents catastrophic wear on bearings, seals, and belts.

Why Get Your Primary Components from Lowbrow?

We offer high-impact parts for every level of customization, all engineered for performance and durability.

A Path for Every Builder: We stock a huge range of custom primary covers for a quick style upgrade, as well as complete, engineered open primary kits for ground-up builds.
Built to Last: Whether it’s a beautifully finished custom cover or a complete Sportster belt drive primary, all our components are made from high-quality materials designed to handle the abuse of the road.

When you choose Lowbrow Customs, you're not just buying parts; you're joining a community of builders. We're committed to backing you up with:

Free Shipping on all US orders over $99.
90-Day Hassle-Free Returns because we stand by what we sell.
Real-Deal Tech Support from our experienced team, ready to offer expert advice for your projects.

Explore our collection of primary drive components and make a bold statement with your build.

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Motorcycle Primary FAQ

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