Motorcycle Repair: 1200 sportster running rich., oil starvation, stock motorcycle

Question
I would hope it was something as simple as Leaning out the carb, but harley davidson has replaced the rings once because harley said the rings failed causing this running problem. then 500 miles later they said the rings failed again, so they replaced the rings, cyclinders and pistons hoping to fix the problem.  now they tell me theres nothing they can do but return my motorcycle back to a stock motorcycle and see if that fixes the problem.   Thanks for your suggestions. Bob
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Followup To

Question -
my 2005 1200 sportster bought brand new with screeming eagle stage 2 pipes and whateevr jet kit is required (all installed by harley when i bought the bike) Runs terrible. i have had it back for warrenty 4 times (6 weeks total) due to dieing at redlights, running very rich, and (what sounds to be like )backfireing through  the carb. they have  replaced the rings twice. and the secound time also the pistons, cyclinders, and rocker boxes. 2900 miles on the bike and stil having simmilar problems.. runs very rich, dies out at redlights,. Harley customer service offers very little help and the dealer cant figure out the problem. any suggestions on what could be wronge before my warrenty is up in 4 months with a broken bike,,,

Answer -
Backfiring through the carb is caused by a rich condition. The dieing is probably from fouled plugs. You need to lean out the intermediate jet.
Why did they have to change the pistons and cylinders?
Mike

Answer
There should be a reason your rings are failing. the things that make them fail is oil starvation, dirt and improper breakin. Like I said before, backfiring throught the exhaust and fouling plugs are a sign of a rich condition. I am not sure why the rings would keep failing unless I saw them.
I think if it were me I would make them give me a new bike since they cant seem to get it fixed. In my state there is a 3 strike lemon law.
Happy 4th
Mike