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Mr. Know It All

AT1MX

TO MX OR NOT TO MX

By Rondo Talbot

 

Dear Mr. Know-It-All,

Not to put any undue pressure on you, but there is a small wager riding on your answer.

Question:

In regards to the Yamaha 125 AT1 MX, what was the first year Yamaha produced this bike using  “AT1 MX” as a model number. We are pretty sure that the first AT1 MX was produced in 1969 but did not come out with the actual designation as “AT1 MX” until 1971. I have checked the “Yamaha Vintage Dirt Bike I.D. Guide” written by Rick Seaman and found the AT Series “AT1 MX” first (and only) noted under “Year 1971”. Please clarify at your earliest possible convenience.

Thanks, previous Owners/Racers of 1969 and 1971 Yamaha 125 MX bikes.

Ward Johnson

Ward,

You are in luck! See around the end of 1968 my BSA A-10 Super Rocket had just broken another crankshaft, and I was ready to do something crazy, nuts, on my next motorcycle purchase. So I shocked all my buddies with their big English Double-Knockers and purchased a 1968 Yamaha AT1MX. It had a white tank, with black pin-stripes. It was a stripped AT1 Enduro with a GYT Kit on it from the factory.

And what was a GYT Kit you ask? A GYT (Genuine Yamaha Tuning) kit consisted of a high compression cylinder head, a ported cylinder, single-ring piston, expansion chamber, bigger carb and a magneto instead of the standard AT1's 12 volt electric start.

The bike also sported big square number plates, with the magneto lacking a lighting coil.

When I showed up at El Mirage the next weekend, my buddies with their big 650's laughed their asses off at the thought of riding with such a dinky little 'ring-ding' motorcycle. Until I beat them all down a giant sandwash. In fact, Bill Heywood seized up his mighty 650 Triumph trying to keep up with me.

It was a great little motorcycle that eventually morphed into a 200cc screamer with a stretched and lowered frame, Curnutts, and a license plate. I owned that little bike for over twenty years.

The last GYT kitted enduro MX bike was the DT1MX released in 1971. In 1972 Yamaha produced the first "real" MX bike the DT2MX.

So while there is a lot of controversy on when the first MX bikes from Yamaha came out, it was at the end of 1968 with the GYT kitted enduro line.

And yes, you really should have known...