...the last time i rode was mid december,seemed to run fine. last weekend barely got around the block. lots of coughing and backfiring.
There are 3 basic variables you want to eliminate, and 2 will always show a presence while the other is a no-show:
1. Compression = One must not chase their tail, so the very first thing is to check compression. Well, say the bike starts right up. We can assume quickly what might not be a cause of starting. So this would be first to be eliminated is it starts, right?
2. Spark = The thing about spark is that a roaring flame and a weak flame can still cause the forest to take off and burn the trees down, right? So changing from a torch to a match is still spark, you changed the ignition and it is still the same. Do we understand we now eliminated 2 variables?
3. Fuel = Here is where you have to think, "I put the bike away and it had spark/fuel/compression when I rode it last." Gas turns to varnish when sitting for a long time. Gas can start the process by shrinking the jetting as it hugs inside the jet hole, wraps a layer around that diameter and narrows the hole.
You get this popping sound, a poor driveability situation when all 3-variables are working. You have spark/compression/but fuel is now in question. Do we understand the spark did not help? Compression is a given? Fuel is, "I left the gas in the carb so it goes bad, and I'm a bad boy for not draining the gas out of the carb to begin with, but now I'm swapping out pistons and ignition systems, what's my problem?
Did we somewhat narrow it down some?