79 Yamaha MX175 – Impulse Buy #2


Another good one popped up on craigslist for $350.
Adam and I decided to buy it together.
Drove 2.5 hours to the tip-top of hickville NJ.
We ended up getting it for a fair price of $300.

In case you didn’t know… Yamaha made “MX” versions of the DT. If you walked into a Yamaha dealership in the 70’s and wanted to buy something 2-stroke to play with in the dirt, you had a few different options:


  • motor tuned for balanced power through the rpms.
  • modest suspension
  • dual sport tires
  • daily rider type bike


  • DT motor tuned for off road riding. Possibly put out a little more HP but can’t find any definitive info on that.
  • Early year MX’s (69-73) it would be a DT1-MX or AT1-MX (MX after the model). These were bikes where you’d walk in the dealer, tell them you want an MX, and they would modify a DT by taking the lights/gauges off and add a couple performance parts (tires/piston/carb/pipe/possibly a GYT kit) to make it an MX.
  • Later years (74 – 82) MX models actually came from the factory as a MX. Like a MX175 (MX before the model). Similar to the early years, it had no lights, gauges, and some performance parts like the exhaust. According to the Clymer manual, these had a better exhaust that would be upgrade from the DT pipe.
  • According to parts list, there was a lighting kit option that you could add on that looked similiar to the IT lights.


  • As close to a YZ as possible.
  • Basically a street legal YZ with lights.
  • Probably de-tuned a tiny bit compared to a YZ?
  • Only made starting in the late 70’s – mid 80’s.
  • No oil injection.
  • IT stood for ‘International Trials’


  • Full off-road race bike.
  • Higher compression motor.
  • Aggressive gearing. Race suspension.
  • No lighting coil or lights.
  • Not possible to make street legal.

There’s not a lot of info out there about all this stuff and Yamaha made so many variations to all these bikes that its been hard to find out all the little details.

One thing that’s interesting about the MX version, is that the VIN number states it’s an “off-road” bike. This is the VIN website to look it up.

The MX and YZ both say “off-road”. The DT and IT says “dual-sport”. So I guess based on that you wouldn’t be able to title and register the MX version? Even if you tried to do the VT registration trick?

Adam is going to try and put the 79 MX175 motor and pipe in his 75 DT175. The newer motor is more powerful and 6spd tranny.
I’m going to use the front end for my CT1-175.

Should be interesting.

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Screen Shot 2014-08-28 at 9.52.05 AM

6 responses to “79 Yamaha MX175 – Impulse Buy #2”

  1. Steve says:

    My impression was that the IT was the enduro/woods bike. Tuned for more midrange than the YZ and suspension made for running over logs rather than jumping 30 ft gaps. Never had turn signals or emissions shit like the DT but could be registered in some, but not all, states.

  2. jorge galeano says:

    Nice bike .i just bought a mx 175 1979 and dt 125 1979. im restoring the dt to my wife and after that , i wanna take care of the mx.

  3. Francisco says:

    Nice motorbikes. I have one Dt 125 (1986) and another Dt 150 (1980).
    It´s the complete Dt model.
    But I am transforming the Dt 150 in a Mx.
    I love this bikes.
    Can you send me a close picture about the logo on the fuel tank?
    I need to made this logo too.
    All the best
    Francisco from Portugal

  4. Michael says:

    Great project. I had a ’74 MX175 and it was one of the most fun bikes I’ve ever owned.

  5. Mike says:

    My first bike was an MX 185 oil injected
    Mo k shock it was way better than my two friends DS 100
    Am I wrong in thinking it was 185 and not 175

  6. Dennis says:

    Hi. I had a 1981 MX175….One of the best bikes I ever had and the first monoshock…I’d ride the fuel out in a day…lol

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