Difference between revisions of "Yamaha TZ250"

==TZ250H==

==TZ250H==

The 1981  "H" represented the factory's first departure from the popular 54mm bore x 54mm stroke (essentially) configuration of the previous 9 years along with a switch to an  individual cylinder casting configuration. In an effort to further boost horsepower, the bore was increased to 56mm and stroke reduced to 50.7mm, achieving the full 249cc in the process and mechanical exhaust power valves were fitted, as was a transmission oil pump to deliver the reduced oil capacity of the gearbox to crucial points. The "H" had a 38mm shorter motor than the "G" and 36mm ZC series Mikuni carbs replaced the usual 34mm SC's, which had been in use on the 250's since the TD3 way back in 1972. Intake port was again widened, as were the secondary transfers for the second year running.

The 1981  "H" represented the factory's first departure from the popular 54mm bore x 54mm stroke (essentially) configuration of the previous 9 years along with a switch to an  individual cylinder casting configuration. In an effort to further boost horsepower, the bore was increased to 56mm and stroke reduced to 50.7mm, achieving the full 249cc in the process and mechanical exhaust power valves were fitted, as was a transmission oil pump to deliver the reduced oil capacity of the gearbox to crucial points. The "H" had a 38mm shorter motor than the "G" and 36mm ZC series Mikuni carbs replaced the usual 34mm SC's, which had been in use on the 250's since the TD3 way back in 1972. Intake port was again widened, as were the secondary transfers for the second year running.