kkawboy14 wrote:
You'r the only guy who would know that!
kkawboy14 wrote:
You'r the only guy who would know that!
Brownstone322 wrote:
Actually, I mostly knew that. The pics are indeed of a 1974 YZ-250A, which debuted that year and quickly overtook the Honda ...more
Brownstone322 wrote:
Actually, I mostly knew that. The pics are indeed of a 1974 YZ-250A, which debuted that year and quickly overtook the Honda CR-250M Elsinore (introduced the previous year) as the best of the new wave of "serious" Japanese motocross bikes (albeit at a much higher price point than the tidy Honda). The original YZs were a separate line of "factory replicas," and that was a big deal back then. (Suzuki's full "RM" line followed in 1976, killing off the half-hearted "TM" line.)
However, I do not recall the terminology "AT1," "DT1" or "RT1." Back then, the "regular" line of Yamaha motocross bikes were called MX-125, MX-250 and MX-360 (in the American market, anyway), and they were closely related to the street-legal "DT" line.
In 1968, the DT-1 250 came out. It was an enduro, or dual purpose. The DT-1MX was a stripped down version with a GYT kit on it, with an unmuffled expansion chamber. The RT-1 was the 360, the AT1 was the 125, the LT was the 100, the HT1 was a 90. The CT-1 was a 175, but they never offered a CT-1MX, as I recall. The DT-2, AT-2, RT-2, etc, was a 1972 model and they changed from a piston port to a reed valved cylinder design. The MX series came in 1974, along with the change to yellow tank and plastic. The previous years were silver based with a color scallop strip different for each model and year. Just a little history. The big change in 1972 was the button mag ignition which had a small flywheel weight, super fast revs and easy to stall. They also lowered the engine cradle on the 250 and 360, which handled better, and allowed a through the frame exhaust pipe to be used. Aluminum Thermo shocks also. A big step up. I rode those things, I was just going into high school. So Cal, good times, riding at Indian Dunes, etc.