What is the most important thing to decide before starting a custom motorcycle build?

Decide how the bike will be used first. Whether it’s for city riding, cross-country touring, camping, or track riding, each purpose points toward different part choices. Once the bike’s intended use is clear, selecting the right components becomes much easier. The How to Build a Bobber guide is a solid starting point for the full build process.

How do I make my motorcycle faster?

Start with a free-flowing air filter and an exhaust system that is properly tuned for your carburetor or fuel injection setup. For greater performance gains, consider increasing engine displacement with a big bore kit and improving airflow with custom camshafts or cylinder head work. Since each modification builds on the previous one, tuning after every upgrade is important.

What should I change first to make my motorcycle more comfortable?

Focus on three key areas: the seat, footpeg position, and handlebar setup. Handlebar rise and pullback typically have the greatest impact on comfort, handling, and riding posture. Investing in a quality seat can also significantly improve comfort on long rides.

Are custom Harley parts compatible with all Harley-Davidson models?

No. Fitment depends on the specific part and model year. Harley-Davidson aftermarket parts are often designed for particular platforms such as Big Twin, Sportster, or Softail models, and compatibility can vary by year range. Always review the fitment information on the product listing before ordering, and contact the supplier if compatibility is unclear.

Custom Motorcycle Parts

Sort by

Custom Motorcycle Parts CATEGORIES

Closeouts

Air Intake & Fuel Systems

Brakes

Drivetrain & Transmission

Electrical & Wiring

Engine

Exhaust

Fenders

Frame & Chassis

Gas tanks

Gauges & Instruments

Handlebars & Controls

License Plates

Lighting

Oil Tanks

Seats

Sissy Bars

Suspension

Tires & Tubes

Wheels & Wheel Components

BEST SELLING BRANDS

TOP Custom Motorcycle Parts

Colony #8702-2 Oil Pump Check Valve Plug 1936-1980 Harley-Davidson Big Twins OEM #26362-36 - Chrome Plated
1 review $12.34

Colony #8905-7 Transmission Shifter Cover Allen Head Screw Kit 1980-1986 Harley-Davidson Big Twin - Chrome Plated
$12.29

Colony #3793-3 Front Seat Mounting Bracket Pin & Lock 1954-1978 Harley-Davidson XL/XLCH
$12.10

Colony #3512-4 Tappet Adjuster Locknuts 1915-1939 Harley-Davidson Singles/45s/74"/80" - Parkerized
$12.10

Colony #3546-2 Handlebar Grips End Plugs 1953-1961 Harley-Davidson K/KH/XL/45's/FL - CAD Plated
$12.10

Colony #3502-10 3/16 x 1/2 Fender to Brace Rivets 1930-1979 Harley-Davidson All Models
$12.10

Colony #3499-10 3/16 x 3/8 Fender to Brace Rivets 1930-1979 Harley-Davidson All Models
$12.10

Colony #3282-4 Rocker Arm Cover Gasket Kit 1936-1947 Harley-Davidson Knucklehead
$12.10

Colony #3268-10 Disc Front Brake Rotor to Hub Screw & Nut Kit 1984-Up Harley-Davidson FXST/FXWG - Zinc Plated
$12.10

Colony #2596-13 S&S Carburetor Allen Screw Kit Harley Davidson - Chrome Plated
4 reviews $12.10

Colony #2807-1 Oversized Transmission and Oil Tank Drain Plug 2000-Up Harley-Davidson Big Twins - Chrome Plated
1 review $12.10

Colony #9305-7 Timing Cover Screw Kit 1970-1980 Harley-Davidson Shovelhead - Chrome Plated
1 review $12.10

Colony #9217-4 Handlebar Bolt Kit Harley-Davidson 1936-1948 Big Twin Springers 1940-Up 45 Springers - Chrome Plated
$12.10

Colony #3758-3 Chain Oiler Adjusting Screw Kit L1950-1964 Harley-Davidson OHV 1958-1969 Servi-car - Parkerized
$12.09

No School Choppers Replacement Bezel Tail Light Gasket 1928 - 1932 Ford Duolamp
$2.41

Mid-USA Replacement Pads for Dual Piston Brake Calipers
$11.99

Cycle Craft #160 Main Jet - 1988-2006 Keihin CV Carburetor
$5.99

Colony #9203-3 Clutch Lever Rod Bolt 1952-1964 Harley-Davidson Big Twin OEM #36921-52 - Chrome Plated
$11.96

Drag Specialties 50A Circuit Breaker 1970-1999 Harley-Davidson Big Twin/XL 1999 Twin Cam
$11.95

Colony #8491-2 Point Cover Screws Cap Head 1971-Up Harley-Davidson Shovelhead/XL - Chrome Plated
1 review $5.96

Colony #9931-8 Intake Manifold to Cylinder Head Allen Kit 1990-1994 Harley-Davidson Big Twin/XL
1 review $5.96

Colony Axle / Wheel Spacer 1-1/8 x 3/4 x 1.875 Harley-Davidson #41595-00 — Colony #41595-00 Axle/Wheel Spacer 1-1/8 x 3/4 x 1.875
2 reviews $11.90

Colony Axle / Wheel Spacer 1-1/4 x 3/4 x 1.690 Harley-Davidson #41591-00 — Colony #41591-00 Axle/Wheel Spacer 1-1/4 x 3/4 x 1.690
$11.90

Colony #8786-5-P Sprocket Cover Smooth Allen Screw Kit 1977-1985 Harley-Davidson Sportster - Chrome Plated
$11.90

Colony #2241-1 1 inch I.D. Axle Spacer 1 inch Thick - Chrome Plated
1 review $11.90

Colony #2196-1 Axle Spacer 1-1/8" O.D. x 3/4" I.D. x 1/4" Thick - Chrome Plated
3 reviews $5.95

Colony #9758-2 Fork Slider Drain Screws Button Head Allen 1977-1984 Harley-Davidson FL 1977-1984 FXWG/FLT 1980-Up Softail - Chrome Plated
5 reviews $5.95

Colony #3210-9 Brake Rod Clevis Pin Kit 1930 - 1969 Harley-Davidson Big Twins — Colony #3210-9 Brake Rod Clevis Pin Kit 1930-1969 Harley-Davidson Big Twins - Parkerized
1 review $11.80

Colony #9985-24 Valve Cover Washers 1954-1965 Harley-Davidson Panhead - CAD Plated
$11.56

Colony #3643-3 Shift Rod Stud 1951-E1979 Harley-Davidson FL - Chrome Plated
$11.55

Colony #8766-10 Handlebar Lever Mount Screws 1973-1981 Harley-Davidson Big Twin/Sportster - Chrome Plated
$11.53

Colony #8747-12 Oil Pump Mounting Kit 1978-1991 Harley-Davidson Shovelhead/Evo - Chrome Plated
$11.53

Colony #3784-2 Oversized Primary Drain Plug 2004-2006 Harley-Davidson Dyna 2004-2006 Softail - Zinc Plated
1 review $11.50

Hawg Supply Weld-On Cable Guide - 5-pack
1 review $11.41

Lowbrow Customs Steering Stem .080" Thick Spacing Washer - Stainless Steel
$5.63

Colony Axle / Wheel Spacer 1-1/4 x 3/4 x 1.437 Harley-Davidson #41591-90 — Colony #41591-90 Axle/Wheel Spacer 1-1/4 x 3/4 x 1.437
$11.17

Colony Axle / Wheel Spacer 1.470 x 25mm x .736 Harley-Davidson #41242-08 — Colony #41242-08 Axle/Wheel Spacer 1.470 x 25mm x .736
3 reviews $11.17

Colony Axle / Wheel Spacer 1-1/8 x 3/4 x 1.242 Harley-Davidson #40915-94 — Colony #40915-94 Axle/Wheel Spacer 1-1/8 x 3/4 x 1.242
1 review $11.17

Colony Axle / Wheel Spacer 1-1/8 x 3/4 x 1.280 Harley-Davidson #40910-84A — Colony #40910-84A Axle/Wheel Spacer 1-1/8 x 3/4 x 1.280
4 reviews $11.17

Colony #2291-8 Front Fender Mounting Kit 1951-1978 Harley-Davidson FL/FLH - CAD Plated
1 review $11.17

Colony #2290-8 Front Fender Mounting Kit 1951-1978 Harley-Davidson FL/FLH - Parkerized
$11.17

Colony #8888-2 Sprocket Cover Screws 1971-1976 Harley-Davidson XL - Chrome Plated
$11.14

Colony #9977-1 Fork Stem Cap 1986-Up Harley-Davidson FLST/FXR/FXD/XL - Chrome Plated
1 review $11.14

Colony #9875-2 Oil Screen Plug 1966-1969 Harley-Davidson Big Twins - CAD Plated
$11.14

Colony #9608-2 Oil Pump Relief Valve Plug 1968-1980 Harley-Davidson Big Twins - CAD Plated
2 reviews $11.14

Colony #9606-2 Oil Pump Relief Valve Plug 1954-1967 Harley-Davidson Big Twin - CAD Plated
$11.14

Colony #2427-3 Clutch Pushrod Adjusting Screw Lock Nut And Ball 1934-1940 Harley-Davidson 45s - Parkerized
$11.13

Gasbox Replacement Oil Tank Mount for Gasbox Horseshoe Oil Tank for Lowbrow Customs Weld-On Sportster Hardtails and Gasbox Full Frames
$5.51

Colony #3756-3 Carburetor Choke Screw/Air Intake Shaft Stop Ball & Spring 1933-1965 Harley-Davidson
$11.00

Colony #3734-4 Tombstone Tail Light Studs 1947-1954 Harley-Davidson - CAD Plated
$11.00

Colony #9675-1 Motor Case Drain Plug 1911-1970 Harley-Davidson 1968-1984 Oil Pump Body - Parkerized
1 review $5.50

Colony #8780-4 Pushrod Tappet Adjuster Locknuts Harley-Davidson OHV Big Twins/45's/XL/K models OEM #18570-38
4 reviews $11.00

Colony #2008-10 Cylinder Head Bolt Washers 1940-1946 Harley-Davidson WLD - Chrome Plated
$10.89

Colony #3791-4 3/4 OD x 5/16" ID x 1/2" Spacers Harley-Davidson OEM #4 52104-38/3209-38 - 4 Pack - CAD Plated
$10.89

Colony #3790-4 3/4 OD x 5/16" ID x 1/2" Spacers Harley-Davidson OEM #4 52104-38/3209-38 - 4 Pack - Parkerized
$10.89

Colony #3419-4 Spacer Replaces Harley-Davidson OEM #61135-52 - CAD Plated
$10.89

Colony #9908-4 Fork Slider Drain Screws 1952-1972 Harley-Davidson K/XL/FX - CAD Plated
$10.76

Colony #2307-3 Headlamp Mounting Kit 1959-Up Harley-Davidson XL/XLH/XLCH - CAD Plated
1 review $10.76

Lowbrow Customs CAD Plated Triumph Tachometer Plug - 1969 and Up Triumph 1/2-20 L.H. Thread
15 reviews $10.55

Morris Magneto Replacement Magneto Cap Screws - Set of 4
$10.52

Colony #2526-4-P Rear Master Cylinder Mounting Kit Smooth Allen 1984-1985 Harley-Davidson FX - Chrome Plated
$10.44

Colony Axle / Wheel Spacer 1-1/4 x 3/4 x 1.125 Harley-Davidson #AS-001 — Colony #AS-001 Axle/Wheel Spacer 1-1/4 x 3/4 x 1.125
1 review $10.44

Colony #2177-8 Footrest and Gear Shifter Mounting Allen Kit 2002-Up Harley-Davidson VRSC - Chrome Plated
$10.42

Colony Axle / Wheel Spacer 1-3/8 x 3/4 x .885 Harley-Davidson #43521-00 — Colony #43521-00 Axle/Wheel Spacer 1-3/8 x 1 x .885
$10.42

Colony Axle / Wheel Spacer 1-1/8 x 3/4 x .890 Harley-Davidson #40910-00 — Colony #40910-00 Axle/Wheel Spacer 1-1/8 x 3/4 x .890
2 reviews $10.42

Colony #2167-2 Upper Crankcase Plug Gasket Kit 2002-Up Harley-Davidson VRSC - Chrome Plated
1 review $10.42

Colony #9780-5 Top Motor Mount Hardware Kit 1932-Up Harley-Davidson 45's - CAD Plated
$10.37

Colony #2046-8 Voltage Regulator Mounting Allen Kit 2000-Up Harley-Davidson Softail - Chrome Plated
1 review $5.18

EMGO Triumph Oil Seal High Gear for 4 Speed Triumph OEM #57-0946
10 reviews $10.30

Colony #3705-2 Brake Caliper Bleeder Screws 2009-Up Harley-Davidson Touring 2008-Up V-Rod - Chrome Plated
$10.29

Colony #3195-2 Brake Caliper Bleeder Screws 2004-Up Harley-Davidson XL 2015-Up Softail - Chrome Plated
1 review $10.29

Colony #8796-4-P Handlebar Clamp Smooth Allen Screw Kit 1982-Up Harley-Davidson FX/XL - Chrome Plated
$10.04

CUSTOM MOTORCYCLE PARTS FOR HARLEY, TRIUMPH, AND BSA BUILDS The parts you choose define the bike. OEM keeps it stock. Aftermarket opens up fitment, finish, and function options the factory never offered. Whether you are sourcing a direct replaceme...

CUSTOM MOTORCYCLE PARTS FOR HARLEY, TRIUMPH, AND BSA BUILDS

The parts you choose define the bike. OEM keeps it stock. Aftermarket opens up fitment, finish, and function options the factory never offered. Whether you are sourcing a direct replacement for a worn component or tracking down a specific piece to finish a chopper or bobber build, the catalog here covers custom Harley parts, BSA, and vintage Triumph across hundreds of categories.

WHY BUILDERS GO AFTERMARKET

Stock parts do the job they were designed for. Aftermarket custom motorcycle parts do what the builder needs:

Fitment Where OEM Falls Short: Finding correct OEM components for older Harley Big Twin, BSA, or vintage Triumph motorcycle parts gets harder every year. Aftermarket and reproduction parts fill those gaps with components built to the same spec or better.
Material and Finish Options: Many aftermarket parts come in finishes the factory never offered, including billet aluminum, stainless, black oxide, and chrome. The part matches the direction of the build rather than fighting it.
Universal Parts for Custom Work: Raw, unfinished, and universal parts give you a starting point to cut, shape, and mount to your specific frame and geometry. That is something a stock replacement never offers, and it is where bobber motorcycle parts and chopper builds get interesting.
Cost and Availability on Older Platforms: For british motorcycle parts and vintage Triumph or older Harley platforms, reproduction aftermarket parts are often the more practical choice on both availability and price.

BRANDS AND WHAT WE STOCK

The catalog covers hardware, fabrication parts, engine components, controls, lighting, and everything in between. Key brands include Colony for hardware and fasteners and Mid-USA for drivetrain and engine components. Fitment data is listed on each product page. If you are not sure what fits your year and model, the team is reachable by chat, phone, or email.

Read less

Custom Motorcycle Parts FAQ

STAY CONNECTED
WITH LOWBROW

NO SPAM, EVER. JUST GREAT STUFF. YOUR INFO IS NEVER SHARED.