Motorcycle Primary
James Gaskets
Primary Cover & Inspection Cover Gasket Kit 8-Hole Primary Cover 1970-1982 Harley-Davidson Shovelhead
$68.87
Cycle Standard
Derby Cover - Chrome - 1970-1998 Harley-Davidson Big Twins
$31.18
British Standard
Triumph Unit 650 Primary Cover Bonneville Tiger Trophy OEM 57-1727
5
$190.35
James Gaskets
Primary Cover Gasket 1965-1988 Harley-Davidson Big Twin
$24.91
British Standard
Primary Gasket for 1963-82 650/750 unit Triumph Motorcycles - Extra Thick OEM #71-7009
64
$16.94
British Standard
Duplex Primary Chain Triumph OEM #60-0477 Made in Japan
3
$54.13
Drag Specialties
Derby Cover - Chrome - 1999-2018 Harley-Davidson Big Twin/Twin Cam
$63.81
British Standard
Primary Chain Tensioner for Triumph Motorcycles OEM #70-6283
9
$42.19
Cycle Standard
3 Hole Chrome Derby Cover for 1970-98 Harley-Davidson Big Twins Replaces OEMs 60668-84A 253952-84T
1
$22.42
James Gaskets
Primary Cover & Inspection Cover Gasket Kit 1984-1986 Harley-Davidson FL/FLH/FX/FXE/FXWG 1984-1988 Softail
$55.23
James Gaskets
Primary Cover Gasket 1977-1990 Harley-Davidson XL
$8.84
James Gaskets
Primary Cover Gasket 1967-1976 Harley-Davidson XL
$6.73
Colony
#8763-20-P Primary Cover Smooth Allen Screw Kit 1980-1984 Shovelhead & Evo 5 speed - Chrome Plated
$37.22
Colony
#3537-17 Primary Cover Allen Screw Kit 1971-Up Harley-Davidson Shovelhead & Evolution 4 Speed
4
$16.34
James Gaskets
Primary Cover Gasket 1952-1969 Harley-Davidson XL
$8.87
Cycle Standard
5 Hole Chrome Derby Cover for Harley-Davidson Big Twins
$26.48
Colony
#3110-1 Chain Oiler Hose Lower Late Style Bracket 1961-1969 Harley-Davidson XLCH - Parkerized
$18.15
Colony
#2071-10 Inner Primary Cover Chain Guard Kit 1936-1964 Harley-Davidson Big Twin - Chrome Plated
1
$14.34
James Gaskets
Primary Cover & Inspection Cover Gasket Kit 8-Hole Primary Cover 1965-1969 Harley-Davidson Big Twins
$68.87
James Gaskets
Primary Cover & Inspection Cover Gasket Kit With Seals 1984-1986 Harley-Davidson FL/FLH/FX/FXE/FXWG 1984-1988 Softail
$68.87
Colony
#3784-2 Oversized Primary Drain Plug 2004-2006 Harley-Davidson Dyna 2004-2006 Softail - Zinc Plated
$11.50
Colony
#7149-11 Acorn Head Primary Cover Screw Kit - 1971-1976 Harley-Davidson Sportster - Chrome Plated
$36.20
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...
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Motorcycle Primary FAQ
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.