Congrats beautiful early example I’m happy that a enduro enthusiast like you found that bike the only thing better if it was me haha

 Looked the 68 DT250 over a bit today. Never studied them before because never thought i would own one. It looks pretty much like the real deal with a few minor parts or items that were replaced or missing for what ever reason over the years. Not much though. Vin starts as DT1 03XXX so not sure where it fits in on production?

It does have the bolt on bracket gas tank, blue high beam, correct speedo with cut out but trip meter knob missing, correct early skinny threaded tire locks, 2 bolt tail light, Turn in tail pipe with rubber cover, correct chain guards, looks like original paper air filter connected to lid.(one piece). matching engine and frame numbers, all controls look original. levers are skinnier where your fingers grab them compared to my 70 or 71 which are original to that model. So i assumed these are earlier levers. Original tires ( slightly weathered) Odd fork boot caps that are flat on top. I assume these are original for the earlier models? never seen them before. 

Going to start it tomorrow. 1st thing i always do is clean the gas tank out, rebuild the petcock and check it for spark. Has good spark, soaking the tank overnight, wasn't real bad. cleaned and rebuilt the petcock. installed new screen filter for the reserve inlet. I was told it may have some kind of noise in the clutch area the last time he had it running. So i will be checking that out after getting it started. Interesting bike for sure. As much as the 70 DT250 is different from the 71, This bike is as much different from the 70 DT250 as the 71 is of the 70.  LoL!  
   

  

On the flat top fork cap, I don't think anyone has answered, my 1968 and my 1970 both had the flat top fork caps.

I think he's talking about the rubber fork dust seal/wipers on the lowers...  I can't remember seeing that style or noticing them being different.

Mark is right. I was talking about the rubber fork dust covers. I checked as many pictures that i could fine online and i think i seen one other 68 DT250 that had them but it was hard to confirm because of the angle of the picture. Yes the fork caps are the same on both bikes and are flat. 
Take a look at the pictures. 1st is the 68 DT250, 2nd is the 70 DT250 or any other Yamaha that i have seen or had.  

  

Installed gas tank back on today and tried starting the 68 DT250. started up 2nd kick, even with the choke not working. after about 30 seconds i knew right away that the left crank bearing was dry, rusted or just plain bad. shut her down, took cover off, water dripped all over the floor. took mag plate off, crank seal was half way out, took it off and sure enough rusty crank bearing. Corrosion everywhere lower half of case. 
Surprise the bike even started, points were all carbon up, dirty, nasty looking. Choke was stuck. Couldn't move the lever to choke it. funny because the carburetor looks like someone just vapor blasted it and looked super clean from the outside. When i took it off, it was nice and clean on the inside too but the needle/seat was stuck? Must have been cleaned and never started or they knew there was a problem with the engine.

Anyways. NOT what i wanted to see or hear. Looks like a complete engine tear down and rebuild. Removed the motor today. Only took about a 1/2 hour on this bike.

This seals the deal on what direction i am going to go with this bike. Restoring the bike to showroom condition is out. To restore it to new or showroom condition would take to much money. Even making it a good clean rider bike is going to get costly now.
 
Couple more different things i notice on this bike is it has a pre formed plastic line for the oil injection line on the pump to the cylinder and the drain plug is hollow on the head and thread side. Very light plug for it's size. Anyone know if its original on these 68's? 


 

  

 

Here is the carburetor condition. looks clean but choke plunger was stuck bad, needle & seat stuck too. I will go thru it again, install a different needle/seat,  jets and rubber o-ring to be safe. 

 

Here are some pictures of the skinny (where your fingers grab) levels and the odd 2 bolt tail light. You can see how thin the levers are then they get wide out by the ball end.  Also checked all the bulbs and surprising there all good. Horn doesn't work. Didn't i read somewhere the horn is unique on the 68? Looks identical to my 70 DT1 horn but there both different from the 71 DT1. 

Because of the moisture damage to the left crank bearing and engine cases it was time to take the engine completely down and go thru it. Funny the upper rod pin and bearing surface of the rod was also corroded. Lower bearing feels fine and is within specs. Cylinder, piston and rings and everything else i can see are very good and looks to match what the mileage shows on the speedo. I have a new set of NOS rings so i am going to install them. Most everything on this engine build is going to be NOS or new Yamaha parts. Should come out nice. Gears, shifting forks and other trans bearing are like new and won't need replacing. All of the moisture was in the ignition side and crankshaft area because of the water that got in there. I did have to get a good replacement flywheel off e-bay. I found a nice one. Identical to the original.
Installing new Koyo 6306 C3 crank bearings, NOS crank seals thanks to Dave( enduronut). All new Yamaha top end bearing, pin and clips. Of coarse replacing all seals, O-rings and gaskets with either NOS or new Yamaha parts. New Yamaha points. Can't believe they cost $70.00 dollars for a set of points! But i stay away from aftermarket points if i can. New clutch plates even though the originals look good.
 
Of course all good engine builds start with the crank. The crank work is getting done tomorrow. I was very lucky to locate and buy 2 NOS 214-11651-00 rods! Although they also cost an arm and a leg! This particular earlier 68 DT250 has a 130mm rod length and a 24mm lower pin. most later ones have a 25mm pin. No markings on the stock rod. the 214 rod looks to be a slight improvement over the stock early rod. 

Nice about these earlier Yamaha engines, there painted. Don't have to polish the engine cases to make them look good. I like it, saves a lot of time. 






 

Nice 70 DT. Was my first enduro.