1971 DT1MX Yamaha
The 1971 DT1MX Yamaha was the last of a breed that started in 1967-68, with the first Yamaha DT1 250 Enduro. Never remembered for good handling qualities, the DT1 did have reliability and strength that made it a natural for dirt biking.
This fact was not lost on the go-fast crowd, and soon the DT1 was the object of desire for many a dirt rider in the early nineteen seventies, since all of us were inveterate tinkerers and modifiers, because that’s how it was if you wanted to go fast. And we were getting sick of our BSAs and Bultacos blowing up underneath us. Enter the Yamaha DT1.
This was the last of the GYT kitted enduro MX line that started in 1968. When you purchased a Yamaha MX what you got was a stripped enduro with a GYT kit (GYT stood for Genuine Yamaha Tuning). The GYT kit comprised of a different cylinder, head, piston, carburetor and expansion chamber. The rest of the machine was an enduro, devoid of lighting equipment, and sported big white square number plates on the forks, and the flanks of the bike.
The machine was over-built, with crankshaft bearings twice the size of other 250s, and a seemingly indestructible transmission/clutch assembly that took serious abuse and came back for more.
The 1971 was also the year Yamaha started getting serious about producing a real off-road motorcycle, with different spring rates in the forks, and a 21” front wheel. This bike also had some pretty radical porting in its piston-port motor; with a one ring piston and 32mm flange Mikuni carburetor (stock on the enduro was a 28 mm). Also, you could see that the GYT kit was somewhat hand fitted, with ports hand shaped, polished and matched. Neat stuff when you think of the reputation Japanese products had back after WWII.
This was the bike that caught the attention of anyone who raced or rode a dirt bike. For $895.00 out the door, you got a fast, reliable and with minor modifications, a decent handling motorcycle that didn’t blow up every other race, and set a new standard for dirt bikes in general. The motorcycle factories in old Europe scoffed at the DT1, until they closed their doors a few short years later that is.
My 1971 DT1MX was modified with a stretched and lowered frame, Curnutt rear shocks, a No1 Products fork kit with top out springs removed, and spacers installed. A 36mm Mikuni carb, with porting and pipe done by EC Burt of Precision Cycles in Lawndale California, a Filtron Air cleaner and Preston Petty fenders completed the package. For less than $1000.00 I had a bike that could run with the Maicos and Huskys of the day, without the ridiculous maintenance rituals the Euro bikes required. The modifications made it a fast, forgiving motorcycle that was reliable too, something unheard of back then.
In 1972 Yamaha designed a completely new motocross machine that shared none of the parts from the Enduro line. The ’72 DT2MX is one of the most sought after vintage dirt bikes on the market, as it was the breakthrough year for Yamaha, abandoning the Enduro design for a real race machine.
But for my money the ’71 was the best, and embodied what dirt biking was all about back then. When you had to modify your dirt motorcycle to be competitive, and loved every minute doing it. 
1972 DT2 MX.
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