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 #2217-8 Motor Case Allen Screw Kit 2004-Up Harley-Davidson Sportster - Chrome Plated
$23.01

Colony #2364-16 Lifter Base Screw Kit 1954-1975 Harley-Davidson Big Twins - Chrome Plated
2 reviews $22.78

Colony #2321-4 Rear Chain Oiler 1954-1962 Harley-Davidson Panhead - CAD Plated
$22.00

Colony #2308-2 Rocker Arm Cover to Frame Bracket Stud Kit 1978-1985 Harley-Davidson XL/XLCH - Zinc Plated
2 reviews $20.31

#2365-16 Lifter Base Screw Kit Special Harley Big Twins 54-75 — Colony #2365-16 Lifter Base Screw Kit 1954-1975 Harley-Davidson Big Twins - CAD Plated
$20.57

Colony #2259-8 Swingarm End Cover and Nut Kit 1993-2004 Harley-Davidson Sportster - Chrome Plated
$21.12

Colony #2368-8 Cylinder Head Motor Brace Mounting Kit 1948-1965 Harley-Davidson Panhead - Parkerized
$20.85

Colony #2351-2 Foot Clutch Lever Pivot Shaft 1936-1940 Harley-Davidson Big Twins1941-1952 45s
$20.88

Colony #2268-10 Rear Fender Strut Low Profile Allen Mounting Kit 2004-Up Harley-Davidson Sportster - Chrome Plated

3 $20.85

Colony #2462-9 Gas Tank Clip Screw Kit 1918-1924 Harley-Davidson JD - Nickel Plated
$20.19

Colony #2180-12 Handlebar Lever Mount Allen Screws2002-Up Harley-Davidson VRSC - Chrome Plated
$20.11

Colony #2527-8 Rear Fender Rail Mounting Kit 1980-1985 Harley-Davidson FXWG - Chrome Plated
$19.48

Colony #2185-4 Upper Bracket BoltAnd Lock Kit 1949-1984 Harley-Davidson FL 1958-1973 Servicar - CAD Plated
$19.36

Colony #2441-3 Brake Shoe Pivot Stud Kit 1935-1951 Harley-Davidson 45's - Parkerized
$18.15

Colony #2357-4 Pike Nut Valve Stem Cap and Locknut Kit - 2 pack - Chrome Plated
$18.10

Colony #2341-5 Front Brake Rotor Button Head Mounting Kit 2006-Up Harley-Davidson Dyna - Chrome Plated
1 review $18.62

Colony #2553-10 Handlebar Lever Mount Allen Screw Kit 2008-Up Harley-Davidson FLT 2006-Up VRSC - Chrome Plated
$17.88

Colony #2378-10 Handlebar Lever Mount Master Cylinder Cover Button Head Screw Kit 2004-Up Harley-Davidson Sportster - Chrome Plated
3 reviews $17.88

Colony #2283-12 Inner Primary Chain Guard Mount 1929-1940 Harley-Davidson 45's 1929-1934 Singles - Parkerized
$25.00

Colony #2222-11 Cam Cover Allen Screw Kit 2004-Up Harley-Davidson Sportster - Chrome Plated
$17.88

Colony #2537-5 Rear Brake Rod Pins 1930-1969 Harley-Davidson Big Twin - 5 pack - Parkerized
$17.40

Colony #2194-4 Valve Stem Cap and Locknut Kit Harley-Davidson 2-Pack - Chrome Plated
$17.88

Colony #2184-2 Stem Nut And Lockwasher Kit 1949-Up Harley-Davidson Wideglide - Chrome Plated
3 reviews $17.88

Colony #2530-6 Gas Tank Allen Mounting Kit 1985-1956 Harley-Davidson FXWG/FXST/FXSB/FXEF - Chrome Plated
1 review $16.70

Colony #2521-4 Front Chain Guard Inner Primary Cover Mounting Kit 1939-1973 Harley-Davidson 45s/Servi-car - Parkerized
$16.70

Colony #2410-1 Pivot Stud 1973-1978 Harley-Davidson Sportster - CAD Plated
$16.70

Colony #2522-6 Rear Fender Rail Mounting Kit 1973-1985 Harley-Davidson FX - Chrome Plated
$16.01

Colony #2272-5 Lower and Upper Fork Bracket Mounting Kit 2004-Up Harley-Davidson - Chrome Plated
$16.38

Colony #2303-3 12mm Brake Line Allen Banjo Bolt 2004-Up Harley-Davidson Sportster - Chrome Plated
$15.64

Colony #2525-1 Slotted Nut Driver for Kick Starter Tripper Nuts 1941-1963 Harley-Davidson 45's - Parkerized
$15.52

Colony #2517-2 Rear Axle Adjusting Screw 2008-Up Harley-Davidson Softail - Chrome Plated
1 review $15.52

Colony #2501-12 Rear Brake Rod Mounting Kit 1930-1969 Harley-Davidson Big Twin - Parkerized
1 review $15.31

Colony #2476-2 Generator Pole Shoe Screws Kit 1958-1969 Harley-Davidson Big Twin 1958-1981 XL - Parkerized
$15.31

Colony #2424-2 Clutch Pushrod Adjusting Screw Locknut 1941-1973 Harley-Davidson WL/WLA/WLC/Servicar - Parkerized
1 review $15.31

Colony #2244-4 Handlebar Riser Hex Bolt Kit 1/2-20 x 3 inch - CAD Plated
$14.89

Colony #2438-5 Gas Tank Pike Nut Mounting Kit 1984-1999 Harley-Davidson Softail - Chrome Plated
1 review $14.83

Colony #2438-5 Gas Tank Pike Nut Mounting Kit 2000-Up Harley-Davidson Softail - Chrome Plated
1 review $14.83

Colony #2242-4 Handlebar Riser Hex Bolt Kit 1/2-20 x 2-1/2 inch - CAD Plated
$14.89

Colony #2227-4 Sprocket Cover Acorn Mounting Kit 2004-Up Harley-Davidson Sportster - Chrome Plated
$14.89

Colony #2360-3 10mm Pike Nut Brake Line Banjo Bolt 3/8-24 Thread - Chrome Plated
$14.16

Colony #2546-1 Wire Clip Frame Head Tube 1950-1960 Harley-Davidson Big Twin - Parkerized
$16.50

Colony #2490-1 Seat Post/Frame Tube/Frame Head Wire Clip 1936-1949 Harley-Davidson Big Twin - Parkerized
$16.50

Colony #2489-1 Frame Head Tube Wire Clip 1961-1984 Harley-Davidson Big Twin - Parkerized
$16.50

Colony #2460-2 Rear Fender Brace Bracket Bolt Kit 1923-1940 Harley-Davidson Twins - Parkerized
$13.92

Colony #2449-1 Wire Clip Rear Frame Harley-Davidson 45s - Parkerized
1 review $13.92

Colony #2353-2 Foot Clutch Lever Bracket Spring Stud 1940-1978 Harley-Davidson Big Twin 1940-1952 45s
$13.92

Colony #2564-3 Rear Brake Caliper Anchor Arm Bolt Kit 1981-1985 Harley-Davidson Big Twin - Chrome Plated
$14.30

Colony #2409-1 Pinion Gear Nut 1954-1989 Harley-Davidson Big Twins
$17.05

Colony #2374-1 Oil Pump Fitting 7/16-20 Thread Harley-Davidson - CAD Plated
$12.53

Colony #2552-2 Carburetor Control Coil Clip 1949-1957 Harley-Davidson 45s 1961-1964 Servi-car - CAD Plated
$14.30

Colony #2481-6 Clutch Spring Guide Stud Lock Nuts 1941-1946 Harley-Davidson Big Twin/45's/Servi-cars - Parkerized
1 review $12.10

Colony #2240-1 1 inch I.D. Axle Spacer 7/8 inch Thick - Chrome Plated
$11.17

Colony #2296-1 Transmission and Oil Tank Drain Plug 2000-Up Harley-Davidson Big Twin - Chrome Plated
$12.10

Colony #2239-1 1 inch I.D. Axle Spacer 3/4 inch Thick - Chrome Plated
1 review $10.42

Colony #2202-1 Axle Spacer 1-1/8" O.D. x 3/4" I.D. x 1" Thick - Chrome Plated
3 reviews $10.42

#2295-1 Transmission and Oil Tank Drain Plug Chrome Harley Big Twin 2000-up — Colony #2295-1 Custom Transmission and Oil Tank Drain Plug 2000-Up Harley-Davidson Big Twin - Chrome Plated
$12.10

Colony #2175-4-P Upper and Lower Front Fork Bracket Mounting Allen Kit 2002-Up Harley-Davidson VRSC - Chrome Plated
$10.04

Colony #2426-2 Clutch Pushrod Adjusting Screw Lock Nut 1936-1940 Harley-Davidson Big Twin - Parkerized
$9.75

Colony #2314-10 12mm Copper Brake Line Banjo Bolt Crush Washers Harley-Davidson OEM #41743-04 -10 pack
1 review $14.52

Colony #2238-1 1 inch I.D. Axle Spacer 5/8 inch Thick - Chrome Plated
2 reviews $9.68

Colony #2526-4 Rear Master Cylinder Allen Mounting Kit 1984-1985 Harley-Davidson FX - Chrome Plated
$9.05

Colony #2524-2 Gas Tank Allen Mounting Kit Pre-1984 Harley-Davidson Big Twin - Chrome Plated
$9.05

Colony #2502-12 Rear Brake Rod Mounting Kit 1935-1952 Harley-Davidson 45's - Parkerized
1 review $9.05

Colony #2266-8 Gas Tank Allen Mounting Kit 2004-Up Harley-Davidson Sportster - Chrome Plated
1 review $8.93

Colony #2249-4 Handlebar Riser Hex Bolt Kit 1/2-13 x 3-3/4 - CAD Plated
2 reviews $8.93

Colony #2247-4 Handlebar Riser Hex Bolt Kit 1/2-13 x 3 - CAD Plated
$8.93

Colony #2329-9 Voltage Regulator Mounting Kit 1965-1969 Harley-Davidson FL/FLH
$8.20

Colony #2236-1 1 inch I.D. Axle Spacer 3/8 inch Thick - Chrome Plated
$8.20

Colony #2455-3 Carburetor Mounting Screws 1937-1939 Harley-Davidson Big Twins 1940 WL/WLD- Parkerized
$7.66

Colony #2376-1 Crank Pin and Sprocket Shaft Nut Harley-Davidson OEM #8010
$11.00

Colony #2326-3 Brake Arm Anchor Stud Kit 1935-1952 Harley-Davidson KL/WL/WLA/WLC - Parkerized
1 review $7.45

Colony #2289-1 Motor Sprocket Nut 1929-Up Harley-Davidson 45s - Parkerized
$9.08

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.