Dead bike w/ new boot, cleaned carb, new plug. Thoughts?

[dimitry]

So after riding sparingly this summer, the bike was last sitting for about a month with petcock not off. Tried to start last week, no luck.

Naturally I thought carb was gunked up from sitting, but it hasn't sat for more than 4 weeks...

What has been done/checked:
- Replaced spark plug. Old one was year old and was pretty black already..
- Checked that we're getting good sparks
- Drained all gas, replaced with fresh gas
- Sprayed a lot of carb cleaner into carb w/o taking it off and it would start right away and die 2-3 seconds later (burning up carb cleaner?)
- Air filter has a lot of gas, so figured.. reversion - replace the boot. Ordered new one, replaced it, nada!
- Pulled the carb and cleaned it more thoroughly, but it didn't look bad at all. Everything was as expected. None of the holes plugged.

We need electric, air and gas to all work.
So electric is fine. Air is fine (trying w/ air cover off for now). Gas was my only guess, but with clean carbs and fresh gas... out of ideas.

Thoughts?

To clarify, it cranks and cranks, but won't turn over.

 

[Iamarchangel]

The Holy Trinity: oxygen (air), fuel, spark at the right time.

Check timing although carb cleaner starts throws some doubt on that.

Compression is also necessary. Piston ring could be stuck/broke. "Pretty black" plug indicates problem. Could be too much oil getting by ring.

Gas into air filter is problem. Shouldn't happen.

Let's assume no gas. Carb float is stuck: works like a toilet. Try gently tapping around bottom of carb with a screwdriver handle.

Was there gas in the carb when you took it apart? Should have been.

 

[dimitry]

It works! So I spoke too soon and just needed to give it a minute. Tried cranking again and it started right up and has been purring ever since. Starts right up.

My guess is carb cleaning helped.

lamarchangel - great info! definitely useful for the future. thank you