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Discussion Starter · #1 ·
99 Legend sitting since October of last year.
Got her up and running again. Well, kinda... she pops and backfires almost constantly above 2500 revs.
I can crank the throttle and she's great until I level out again.
2 into 1 on right side and only the right side is popping.
I added some Sea Foam to the gas when I fueled up.
Any thoughts ? I'm thinking jets but don't really want to tear carbs out.
 

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Have you checked anything?

Things I'd checked
Fuel tank for rust
Fuel tap and duck bill filters for sediment (if found, possibly clean carbs)
If the fuel stood all winter without stabilizer, then I'd probably discard it and get some fresh (may have built up water via condensation)
Carb Rubbers / Air Filter - solid, not eaten or deteriorated while laid up

If those are good then I'd check Ignition - wires and coils.

Scott
 

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+1 to avu3's suggestions. Pretty much got to be a fuel system issue, most likely jets or filters, tho' might add a diaphragm check to the list while you're in there. Symptoms don't really fit coil or pick problems. Tho' corroded LT or HT ignition circuit connections are just possible perhaps.
 

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I know I'm going to be the odd man out by saying this. I would try a fresh set of spark plugs before I dived into the carbs. Backfiring shows you have more fuel available than you can burn. I have had plugs go south from sitting before. Especally in a humid climate. ...J.D.
 

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What happened to the original poster?

Technically, a back fire is through the carburetor. If you're hearing it in the exhaust it's an after fire. After firing is caused either by too lean a mixture (which burns slower and is still burning when the exhaust valve opens) or a sticky exhaust valve which lets the fire out before it should. If the engine is misfiring it can also pump un-burnt fuel into the exhaust which is then ignited by a subsequent firing of that cylinder or the other cylinder paired with that exhaust.

If it is a miss caused by ignition I would not expect it to improve under full throttle, so, at this point, my money is on the carburetor(s), However, swapping plugs is not difficult so you might at least want to look at them first.
 

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Discussion Starter · #6 ·
The original poster is here WSC. I have been adjusting the air/fuel mixture. I also Drew seafoam carburetor and injector cleaner directly into the carbs through the vacuum lines. She seems to run better when I leave the center carb vacuum intake unblocked with no cap. But still won't run right. It may be time for new plugs anyways because to my knowledge these have 12,000 miles on them. So I will keep trying the different options because I really do not want to tell the carburetors off
 

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If bike has been sitting since October with ethanol gas, there's the problem.
Likely require at least a carb tear-down. Any rubber parts will be shot.
 

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12 k on the plugs, I'd change them no matter what else is going on! I greatly prefer the iridium plugs, despite the higher cost. The iridium electrode will outlast regular ones many times over. and they seem to be much more fouling-resistant and have a more robust spark. The extra couple $ each is way more than offset by not feeling the need to have to change that center plug!
 

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Discussion Starter · #10 ·
That center plug.....that's why I haven't changed the plugs yet !!!!
Lame, I know
 
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