Motorcycle Repair: cb350 1973, plug caps, air leaks

Question
my 350 cant start last running 3 months ago had some backfire out muffler ran good stillroad it about a mile drained gas for winter has spark new gas points are gaped at 14turn overand over but it just doesent give that want to fire sound.138 miles ago had new coil carbs tuned a full tune up bike had a little more sound from motor adjust cam or valves a idea in the right direction what the steps for or better yet what your opion if you have time would be great

Answer
Brad, you have to go back to the basics...

Pull the plugs, check for spark at each one.
No spark, check the points for corrosion on the point faces and voltage to them.

Be sure that the mechanical advancer is still working okay.
Check compression to verify that you don't have a valve hanging open from a little moisture/rust buildup on the seats. Should be about 160-175psi with throttle held open.

Back fire could be from bad carb diaphragm, air leaks at manifolds, incorrect float level.

Check your choke linkage to see that both sides are closing together and that the little flaps are still working on the choke butterflies.

Fresh fuel and fresh plugs. Check both plug caps for matching resistance... around 5K ohms.

Valve settings are .002" and .004"  In/Ex

With the point cover off and cranking the engine, check for excessive sparking across the points, indicating a disconnected or defective condensor.

Start with a fully charged battery.... make sure that the kill switch is set to ON and that there are no issues with the power going through it.

Bill Silver