Hi Folks.  Full disclosure, I joined primarily to get an answer to the question: What exactly is this?  This bike was bought by my step-dad in either the very late 70’s or the early 80’s because I was riding a GT80 and he thought he wanted to ride with me.  But he was very inexperienced and after burning him rather badly and tossing him on his hat a couple times, it got parked for a decade.  I continued a love of all things motorcycle and he eventually gave it to me.  I’ve played around with most types of motorcycle racing (MX, Enduro, Road Racing, Trials, Ice, etc.) without talent or distinction and took this bike to AHRMA, where I entered several events.  I eventually settled into modern KTM’s for off-road purposes but have always kept this around.  Now I’m getting into a mild restoration but I don’t really know what it is.  My best guess is that it is a DT250 with some kind of MX kit.  The lower end has a disabled oil pump assembly, but it’s been premix as long as I’ve known it (40+ years).  The half fender and air box can’t be stock, and the rims are racy as well.  I read somewhere that someone (maybe even Yamaha) made an MX kit for the DT’s?  But the head and jug don’t look DT to me.  Any ideas?  Thanks!

Greetings from Tennessee. 
   You can look up your VIN in the tech library to see what you have and others will be along to chime in you can get a lot of info and advice here just ask away honestly this is the best forum you will find bar none 

Brilliant!  Apparently, I have a 1972 DT2MX.  What do I need to know about them?  I understand that the power band is a light switch and that there’s a hinge in the middle, but does anybody know the history of this model?

Thanks,
AC

Fairly rare from what little I know.  Quite fast for the day... and suspension tech.  Not surprised it bit your Dad a few times. 

Several experts on here know a lot about them...  hopefully they'll see this and chime in. 

Here's mine from 50 years ago. Great bike. First true production motocrosser & if you discount the DT1MX. I wouldn't say it had lightswitch power but had plenty that's for sure. The 360 identical looking bike was damn scary & turbo'd on very hard. Both had small rotor ignition with 250 having small rotor points mag & 360 had CDI. You 'might' find someone has fitted a flywheel mag off a DT1 or similar & say that because the mag cover looks DT where original was more fitting to shape closer to the small mag. If it has a flywheel then that will tame it very well to be more useable. Anyway--lucky you & i want one haha. What country are you in--i'm in little ol NZ down under. Welcome to the site. 

Hammerhead shocks!

Redwings!  Johnny Deemer (a name that some of you might know) sold them to me for a bargain price when he and Jack Leece were running Slick’s Great Lakes Salvage.  They are old friends (yes, I’m bragging and name-dropping) and I will be with Johnny tonight at the annual Daytona watch party at the Bluegill Grill at Lake Lansing.  Gonna be a fun night!