I've been trying to get the DT-1 running for some fun time out in the desert. I cannot seem to get it started.  Today after replacing the mag side crank seal I got it running long enough for 1 lap around the back yard, just started to get a screw driver to do some air/fuel adjustments when it quit and now will not start.
4 months ago it started fine and ran it around the hood for a while, it performed excellent.
So far I have: rebuilt/cleaned the carb (running 95 octane non-ethanol fuel)
                       replaced the mag side crank seal (good quality double lip was used)
                       did a compression test, result: 75pounds at closed throttle, 80 at wide open throttle.
Every time I pull the plug it does not look "wet", so I'm thinking it's leaking air some place and won't pull fuel??
I suppose next I should do a cylinder leak down test??
Oh, also last spring the head was off and removed the carbon; which was not excessive, and it ran great afterwards!
I'm ready for any and all suggestions from all, help!
One other thing: How important is the rubber (small) cap that detains the starter plunger; it is cracked. A new one was not included in the carb rebuild kit?
Thanks for any help.

 

Do a bubble test on the new seal. Pull the stator back off. Spray it with some soapy water, kickstart the bike with the spark plug in and see if you’re blowing bubbles out the left seal. If you are replace it again.

a

My guess seeing it ran around the yard--is-- crank key [flywheel locating key] has let go from flywheel 'not' being tight enough.

Also, have you cleaned the faces of the points contacts? Reach in with a piece of worn out 600 or a business card, and with the points closed, drag it out, first one way, and then the other.

Thanks for the suggestions to all. I pulled the flywheel and stator plate again and did the bubble test. I'm seeing no evidence of any leaking there. The flywheel is engaged with the crank properly and the contact points have been serviced; however the bike still will not start. Have checked for spark with the plug out, and I see a nice blue arc. Like I said before this was a running bike 4 months ago, and has never sat with fuel in the carb that might gum things up, I've been through the carb several times now but, is there something I'm missing? It just does not want to pull any fuel into the cylinder.
I'm thinking after the upcoming holiday I will look at the top end, piston and ring? I wonder if I can do a leak down test on the cylinder the same as for a 4 stoke engine?
Thanks again for the tips and I'll be waiting to hear of any other ideas.
 

Is the timing correct? I would retorque the head check the intake manifold is it tight get a new spark plug and gap then put some starting fluid in the cylinder install the plug quick and start. I know some people will disagree on starting fluid but it want hurt we did it at Butler’s if needed 

I always cringe when someone says they rebuilt a carb using a "kit". Stick with genuine Mikuni jets and needles.

Float bowl to jet setter o-ring is critical, some "kits" don't have the correct o-ring but that generally runs rich.

My guess is that pilot jet or passage is plugged from what you've said or possibly float valve stuck closed? Other common thing is flooded or simply a bad spark plug that won't spark under compression.

I'd give a shot of starting fluid a try as well.

P.S. Do not use a "four stroke" leak down tester as you may blow out the crank seals.

So something happened on the spot while you went to get a screw driver. Not wire let go on the condenser. Will still spark but not under compression. Right side crank seal fell out. Not sure if those had a circlip to hold it in like later ones. Only thinking along those lines as you say 'has no suck'.

If it hadn't been running prior i might think--Exhaust blocked to the extreme--can't blow so won't suck--umm, ok stop being stupid 'me'--but, i had a long parked weedeater once that a mason bee had sealed the exhaust 100% & no blow so no suck.

Also be sure your getting good fuel flow from your gas tank and petcock. Gas tank cap off or loosen up to be sure it's venting good. Petcock plugged? Like others have said a small shot starting fluid or some fuel in a spray bottle into the back of carburetor will tell you if your not getting fuel. Open the throttle when doing this.

Mine sheered off once after starting briefly, that’s where I’d check first. The old woodruff key