The 250 has:
about 30 more pounds
33 mm forks rather than 31
sturdier triple clamps (note that Honda made an optional fork brace for the 125-evidence of sloppiness here)
a more trials-like steering geometry (125 has same triple clamps as SL series)
an aluminum fuel tank (they may dent and they may leak but they never rust)
a lighting coil (only TL125S models came with one)
a factory installed chain tensioner
a sturdier swing arm with proper bushings, not rubber flexy things
shocks with 11mm shafts, not 8
thicker spokes
a detachable skid plate
no need to fold the right peg to kickstart
about 3 inches more wheelbase (52 vs 49 inches)
Sammy Miller design. 'Nuff said.
As to the tl250 engine being greatly different than its XL brothers, I think not. Gears are mostly different, but they last forever at the output mandated by its 24mm carb. Cylinder head has smaller ports than XL. Pistons, cams, rockers, valves, gaskets same as XL.. Crank has the larger main bearings common to 350s and later model 250s.
Too heavy and unresponsive for most people to do much in the way of trials with them, but the TL250 makes an outstanding trail bike, provided you're not in a hurry.
Cosmetics, notably side panels, impossible to find or very expensive. But as side panels are functionless, who cares?
BJ racing has most everything else.
Finally, remember what trials great Mick Andrews said (circa 1973) when asked about the latest crop of 125cc trials bikes: "I don't like mini-bikes."
) I have been told that the frame geometry of the 125 is more suited to Trials that the 250 (I have read that Honda didn't think it could sell enough "trials-only" 250's, so they stretched out the front end to make it more stable on trails at speed and still only made them for two years, while most of the "works" bikes went to the crusher). I don't see to many 250's in AHRMA or STRA Vintage, but I do see a LOT of 125's...and with the TMI down for repairs, it looks like I will be campaigning the TL250 this year...
