Jeff Henise
Highwayman Bikes
250gp. two stroke hp chart from many sources and is my best guess and can change without notice.
| year | model | claimed crank | est crank hp | measured crank | measured true rear wheel hp | dynojet style hp | 
| (true x 1.1) | (crank x .9) | (true x 1.15) | ||||
| 1959/1960 | yds1r, air cooled | ?? | ||||
| 1962 | td1, air cooled | ?? | ||||
| 1963 | td1a, air cooled | ?? | ||||
| 1965 | td1b, air cooled | 35hp (from someone's memory of Yamaha's claim) | ||||
| 1967 | td1c, air cooled | ?? | ||||
| 1969 | td2, air cooled | 44hp (from Yamaha) | ||||
| 1971 | td2b, air cooled | 47hp (from Yamaha) | ||||
| 1972 | td3, air cooled | 49hp (from Yamaha) | 40 measured with stock expansion chambers | 46ish djhp | ||
| 1973 | ta250 (td3 engine, tz250 frame) | 49hp (from Yamaha) | 40 measured with stock expansion chambers | 46ish djhp | ||
| 1973 | tz250a, watercooled | 51hp (from Yamaha) | est 43 | |||
| 1976 | tz250c, monoshock | 52-53hp (from Yamaha) | est 44-45 | |||
| 1977 | tz250d, stock | 52-53hp (from Yamaha) | est 44-45 | |||
| 1977 | Morbidelli rotary valve, parallel twin rider: | 72 measured @ output shaft by Morbidelli | estimated 65 true rear wheel hp | 75ish djhp | ||
| 1978 | tz250e, stock | 53hp (from Yamaha) | estimated 45 true rear wheel hp | 52ish djhp | ||
| 1978 | tz250e mod, world class rider: | 66 measured @ output shaft by Morbidelli | estimated 59 true rear wheel hp | 68ish djhp | ||
| 1978 | Morbidelli rotary valve, parallel twin rider: | 72 measured @ output shaft by Morbidelli | estimated 65 true rear wheel hp | 75ish djhp | ||
| 1979 | tz250f, stock | 53hp (from Yamaha) | estimated 45 true rear wheel hp | 45ish djhp | ||
| 1979 | Morbidelli rotary valve, parallel twin rider: Graziano Rossi | 72 measured @ output shaft by Morbidelli | estimated 65 true rear wheel hp | 75ish djhp | ||
| 1980 | tz250g, stock | 55hp (from Yamaha) | estimated 46-47 true rear wheel hp | 54ish djhp | ||
| 1981 | tz250h, stock | 57hp (from Yamaha) | estimated 48-49 true rear wheel hp | 56ish djhp | ||
| 1982 | tz250j, stock | 57hp (from Yamaha) | estimated 48-49 true rear wheel hp | 56ish djhp | ||
| 1990 | tz250A, 3TC, stock | ? | ? | ? | ? | |
| 1990 | tz250A, 3TC, many mods | est 75-76 | 66 measured true rear wheel (many mods) | 76ish djhp | ||
| 1991 | tz250b, 3YL, monoshock | |||||
| 1992 | tz250, 4DP1, monoshock | |||||
| 1993 | tz250, 4DP2, monoshock | |||||
| 1994 | tz250F, monoshock | |||||
| 1995 | tz250G, monoshock | |||||
| 1996 | tz250H, monoshock | |||||
| 1997 | tz250J, monoshock | |||||
| 1998 | tz250K, monoshock | |||||
| 1999 | tz250L, monoshock | |||||
| 2000 | tz250M, 5KE, monoshock | |||||
| 2001 | tz250N, 5KE, monoshock | |||||
| 2002 | tz250O, 5KE, monoshock | |||||
| 2002-2009 | tz250P, monoshock | |||||
| late v type | tz250, stock | est 72-73 | 66 measured true rear wheel (stock engine) | 76ish djhp | ||
| late v type | tz250, USA mod engine | est 82-83 | 74-75 measured true rear wheel (modified engine) | 86ish djhp | ||
| rotary valve twin type | 250 | est 88-89 | 80-82 measured true rear wheel | 92ish djhp | 
Some claimed hp from information from http://www.tz350.net/tz250page.htm