1979 Suzuki dt25 wont start

[shawnvv]

Hey guys, I acquired a 1979 dt25 and I'm trying to trouble shoot why it won't start. It has fuel and spark. It coughs and spits but won't idle. I'm wondering if there is a way to check timing. I see the timing marks on the flywheel but not where to reference them to. It has electric start so turning the engine over is no problem.
Any ideas would be great
Shawn

 

[shawnvv]

Doing a little more tinkering i've discovered that there isn't very much airflow through the carb during cranking. Possible blown crank seal? Sucking air through the crank instead of the carb.
Shawn

 

[ERock82]

If it has fuel and spark, and is turning over then it should start if for just a moment. Make sure it really is turning over. If not that's either bad starter or connections. Make sure plugs are on tight and boots are secured and not corroded inside. Check how hard the bulb gets. If it gets hard, like it should, it prob isn't the carb. Check the carb for flooding and make minor adjustments to fuel air screw on there. As long as you get some consistent flow of fuel from carb into cylinders, it should start.

 

[Propwash79]

I would think wih a motor that old I would do a compression check. If it's smooth and easy to pull on the starter rope then you have compression issues,could be rings or a hole in the piston. If the compression checks out (higher than 65psi then see if your getting blow by to the other cylinder. Pull he spark plugs and put a piece of rubber tubing in the spark plug hole that fits snug and blow into it and see if your getting air out of the other cylinder. Don't use compressed air cause it will blow the seals for sure.