Bike decided not to start ... fires on , then backfires

Well Son of a Bi%#h ! Since I changed the oil filter , the Bike Doesnot want to Idle. It Fires , headlight comes on then it backfires LOUD! It was running fine a week before . I charged the battery, Put new gas in , and topped up the oil ... Stubborn Yam . any clues ... Do I have to clean the carbs AGAIN?

 

Weird. Changing the oil filter shouldn't have a negative effect. Something else obviously happened since then. If it doesn't want to idle and backfires, it might be running way too lean. Make sure the mixture screws are all turned out the same 2.75 turns. Also, put half a bottle of gas-line antifreeze (aka methyl hydrate} in a full tank of gas. You may have collected some moisture in the new fuel. And check your air filter and airbox. Anything blocking it? Is it dirty? Finally, check your battery. If it's not up to a full charge, you will get ignition problems.
thx,
baz

 

Charge your battery, and change your plugs. Try to start it. Just went through the same thing with mine after cleaning the carbs. It got so flooded that it kept acting like the battery was dead (cranking over slowly). I pulled the plugs and drained the oil and let it air out for several hours. Put it back together and it finally runs - I'm going to put new plugs in it now because the old ones have been soaked too much and it still runs a little rough.

 

The first this I ve done was replace the spark plugs,installed a new battery, Drained the oil, and oil filter, Ran two cycles of 20w 50. Put fresh gas in . Started fine the night before it fired up idled a bit high. Now after sitting for 3 days It just wants to fire up and backfire. I should mention It smells gassy when it backfires.. could it be flooded? how do I fix that. What bugs me was ot was starting and idleing fine (well for a bike that was just sitting for a year)
Now she just spits out backfires. Seems to happen from the carb area as well .

 

Do you have gasoline mixed with the oil? If so you probably have a float chamber needle valve that is leaking. It leaks into the cylinder and then down into the lower engine, eventually as enough builds up it will spew out of the overflow and into your airbox, ruining 2 filters and the oil!! Luvly

 

If it sat for a year you most likely had build-up in the Air-Fuel Passages that dislodged and is now clogging-up the tiny Ports needed to get Fuel to the top-end for Idle and Start.

Try using Starting Fluid and/or Propane Gas in the Airbox to see if it is a Fuel related problem or something else.
If it fires-up with an external source of Fuel ... you'll have to revisit the Carb Cleaning to eliminate the blockages in the Air~Fuel Passages.

You should flush the Pilot Jet Passages with the Pilot Screws and Pilot Jets removed.

If you don't think that the Carbs need Cleaning, again ... try deliberately setting the Pilot Mixture Screws a tab Rich and see if it will run.
A tad Rich would be slightly over three turns out from the bottom.
Not quite 3-1/4 Turns out.
Beyond 3
But, closer to 3 than 3-1/4.

 

Well it dawned on me this morning , My bike was knocked over then stood back up says my neighbor... The rear flasher was bent in slightly. I just adjusted it . He said that gas was coming out of a black hose....

G'damn! tells me 2 weeks later . Lucky I like the guys family. No Damage is done that I can see... AND explains why it will not start , as I could imagine there is not enough fuel in the carbs or to much . when I put it on "PRI" I dont see or hear gas going into the carb body..(I have a clear gas line)... so , what to do when The bike has been knocked over?

 

Well it dawned on me this morning , My bike was knocked over then stood back up says my neighbor... The rear flasher was bent in slightly. I just adjusted it . He said that gas was coming out of a black hose....

G'damn! tells me 2 weeks later . Lucky I like the guys family. No Damage is done that I can see... AND explains why it will not start , as I could imagine there is not enough fuel in the carbs or to much . SOOO, what to do when The bike has been knocked over?