running crappy and dies at idle

New plugs, wires, fuel lines and filters, points cleaned and gapped, fresh oil and gas, also added half bottle " mechanic in a bottle" as it has been sitting for awhile. Ran great for a couple days, then started breaking up and running shitty. Found rust in tank..could this be maiking it to carbs and causing this issue?

Do the carb bowls have drains?
If so, drain the bowls into a little cup, and see if any particles are in there.
I've seen little black bits in my bowls in the past.
Fuel filters can deteriorate over time, and the new ethanol gas doesn't help, so a new filter may be needed.
Any bits getting into the carbs can cause problems, and the carbs may need a cleaning to clear them out.

What is the air filter's condition?
Clean, stock filter?

Do you have an inline filter between the tank and carbs? If not, it's possible that some rust from the tank has clogged up the carb internals. If you clean the carbs I would recommend you install an inline filter before connecting the fuel line to the tank, otherwise you may very quickly end up with dirty carbs again.

If you do decide to install or replace an inline filter I would not get one that has a paper element. The one I have has a stainless steel element, so it cannot deteriorate and cause problems. Ed

oldsguy wrote: New plugs, wires, fuel lines and filters, points cleaned and gapped, fresh oil and gas, also added half bottle " mechanic in a bottle" as it has been sitting for awhile. Ran great for a couple days, then started breaking up and running shitty. Found rust in tank..could this be maiking it to carbs and causing this issue?

YES Rust and sediment runs downhill and blocks jets in the carbs. Take the tank and petcock off and clean thoroughly, install new inline filters and clean carbs.

The pilots get clogged first. Use a guitar string or wire brush strand to clear them. And put some inline filters on. The bullet plastic ones are $5 at your Yamaha or other shop. If they last a year it's well worth it.
Steve

Filters and lines are new, and air filters are K n N cone style. Thanks for advice..will pull bowls and clean carbs..replace filters and see what happens

I see some guys selling welding tip cleaners as carb cleaning tools.... I have those too, for the right reason and certainly not cleaning carbs.
But I haven't found anything as good as a .009"-.010" high E string from an electric guitar!!
I keep, in a tall skinny medicine bottle, a number of different dia guitar strings but the largest that will fit those tiny (nearly impossible to clear out with out using a guitar sting) offices .... .016".

My choice"
.009", .012" and .016"

And like Bounty hunter suggested, ..remove the petcock & check that the screen on it is free of any rust or debris
Pete

Found no gaskets between floatbowls and carb..could this cause a problem?

Leaks !! ...are those the original carbs ? ..are you sure there are no paper or rubber O-Ring type gaskets
Pete

Nothing..and #1 carb was wet around area of bowl and underneath.