Which bike to build from
In-depth, sourced guides for the classic donors — engine, the real common problems, what to check before you buy, and a realistic value. Then value your exact build in the calculator.
Honda CB750 (SOHC)
1969–1978 (SOHC; K0–K8 plus sportier F variants)
Honda CB550
1974–1978 (CB550K; CB550F 'Super Sport' 1975–1977)
Yamaha XS650
1970–1985 worldwide (XS-1 → XS650 → Special; US sales ended 1983)
Honda CX500
1978–1982 (base; Custom, Deluxe, Turbo and Eurosport variants alongside)
Yamaha SR400 / SR500
SR400 (Japan) 1978–2021; SR500 (US 1978–81, Europe 1978–83)
Suzuki GS550
1977 onward (E, L, ES/M variants ran into the mid-1980s)
Harley-Davidson Sportster (Ironhead & Evo)
Ironhead 1957–1985; Evolution 1986–2003 (rigid-mount)
BMW R100 airhead
1976–1996 (production paused and restarted in 1985)
Kawasaki KZ650 / Z650
1976–1983 (base + SR from 1979, LTD from 1980; electronic ignition from 1981)
BMW R65 airhead
1978–1993 (twin-shock 1978–84; R65LS 1981–84; Monolever 1985–93)
Triumph Bonneville (Hinckley, air-cooled)
2001–2016 (Bonneville, T100, Thruxton, Scrambler and more)
Kawasaki W650
1999–2007 (US/Canada 2000–2001 only); succeeded by the fuel-injected W800
Suzuki SV650 (first-gen carb)
First-gen carburetted 1999–2002 (fuel injection from 2003)
Suzuki Savage / LS650 (S40)
1986–2020 (LS650 Savage 1986–2004; renamed Boulevard S40 from 2005; 5-speed from 1993)
Also valued in the calculator
60 more donors have market values built into the tool; deep guides are added over time.