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:

DT

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

MX

• 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.

IT

• 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’

YZ

• 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?

Anyway…
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.

All were 69-71 era, piston port motors, before Yamaha really knew what dirt bikes would become. And all were relatively about the same dimensions, just different weight.

Lately I’ve been regretting buying my 71 CT1 since it’s lacking the newer technology compared to the late 70’s. I really wish I had bought a 78-82 dt175 instead; way better suspension and faster.

Regardless… I’ve been looking at ways to make mine better from a performance and suspension standpoint and after finding all these cool images, it gives me some solid inspiration. Some of these bikes below are badass! This is what I’m thinking:
– already have pod filter and jetted carb
– GYT expansion chamber exhaust
– aluminum rims. small front hub. no front brake
– plastic front and rear fender
– smaller front gear. bigger rear gear
– front end from a YZ or MX
– maybe take all my lights off and put a number plate on it

Yamaha had a power kit from the factory called “GYT”. (Genuine Yamaha Tuning)

You could walk into a Yamaha dealer in 1970 and get a new piston kit / carb / gear / exhaust (all yamaha parts) to make it go faster. I’m trying to find some of this stuff on eBay but its super rare.

FYI – the hot exhausts were:
– GYT
– hooker
– DG performance
– torque engineering
– bassani
– moto tech