Thank you so much Schu!  Great pics.  If I decide to pull the right case apart to investigate, after draining the oil and removing the oil pump, can I replace the crank seal without disassembling the clutch?  I have a Clymers but the protocols seem to assume complete engine teardown. Pat. 

PS  There are several other responses to my problem so I'll try to post the current update only once ().

What a great reply MarkT,

During the past 51 years this cherished Enduro has always started, run well, and been licensed.  4 years ago my son took it to Atlanta when his family moved there for work.  It has mostly sat all that time.  For some reason he played with the carb floats.  Brings the bike back to me (after divorce) in a U-haul about a year ago.  I've been able to start it with a little effort but always runs poorly at all rpm's and smokes.  Since, I've replaced coil/plug, air filter, totally rebuilt carb (including new O-ring and float fork adjustment and trying main jets from 90 - 220), flushed exhaust, and had CDI bench tested (good).  Found out later that the tie-downs got loose for the last 700 miles of my son's return trip from ATL and the bike laid on the floor.  So, tomorrow I'm going to do a compression and leak down test (saw a little scoring on piston and cylinder wall when I took off the exhaust).  If that's good, I might try to run it for an hour or more and see what happens, or break the case open and see if the crank seal has dislodged.  In any case, your advice is greatly appreciated.  Respect, Pat

Here are a few extra pics just to get familiar w/cover off.

clutchp paks out. note, where Shu's finger is stick a rag there to bind and undo the crank gear nut or use a clutch tool before taking off clutch.
take care to note order of parts removal for clutch.

Thank you so much PABDT! Those pics might come in very handy. By "clutchp paks out" do you mean that when the nut is removed, I can just pull the entire clutch assembly off whole? Pat

I’m not sure if you can replace that crank seal with the clutch basket installed. I’ve always removed it. I ended up making a seal press kit out of stuff I had laying around. I cobbled up a huge flat washer with notches to clear the various bosses that stick out beyond flush. Then I stacked various washers to allow me to use the stock hex nut to press in the new seal nice and square without being skewed or set too deep. I’m sure there are lots of ways to accomplish this task but I always like to MacGyver. Lol

youtube.com/shorts/JDq0PwSc9AY?feature=shared

youtube.com/shorts/4USk-V55UWw?feature=shared

Schu is there any chance you will make a scale drawing of that washer press tool? I would love to have one on standby

Me too "McGyvering"!

No problem. I will make a tracing with dimensions. Keep in mind that this does induce a side load into the rotating assembly as it draws the seal into the bore. But I doubt it's enough to cause problems. At least it hasn't for me. It might be a few days before I can get at it.  My grandson is coming to stay with me for a week!  

Thanks Schu!  I have a 9 yo  I had given my DT360 to him for when he turned
 

I always wondered how a crank seal blows out.
Hydro lock is one for sure.

Another is ratcheting.
If the end of the seal is beyond the machined bore/face, heating and cooling works the seal out.

Heating softens the rubber and the 1.4/1 average primary compression ratio tends to push it out.
Upon cooling, the sharp machined edge locks the new position.

Do this a few/many times and this ratcheting overcomes the press force of the seal in the bore.
Pop goes the weasel.

sketch coming soon....

c