The black silt in the muffler sounds like a symptom of a sticking choke cable or some other problem making it run rich. I hope they went ahead and changed the choke cable while they had it for 3 weeks. Mufflers don't clog up on thier own.

 

They put a new choke cable on and said it was the same as the one the was on there.

 

Chief

What is the alltitude you reside at? The reason I ask is if you are high say around 3000ft the bike is already set rich from the factory and the altitude could be affecting your run rich satutus. When they changed the choke cable they will have had to monkey around with the springs attaching the plungers. Chances are they broke free any stickiness that might have occurred. If I were you I would get into those springs change them out yourself then you will now there will be no more trouble.

 

altoys, I'm not too sure of my altitude. I'm in northeast pennsylvania. The flakes in the muffler were metal. We brought a magnet to them and all the little pieces went right to it. For how long they had it the choke should be fine I would think.

 

gtchief

Since you had the muffler replaced is it running ok, and have you done a sparkplug test? Here is a good way to look at your sparks. Change to new sparks set up a 1 mile run so you can ride at 3/4 throttle for that mile. At the end of the mile hit the kill switch keeping the trottle at 3/4 untill you are stopped. Turn off the bike take out the sparks where you are stopped and check the colour. This will tell you how your bike is running. Every time you make the 1 mile run put in new sparks. Four strokes are easy to set for jets, if it is too lean you will have a powder on the electrodes, if to rich there will be black on the electrodes. Go higher with jets untill there is no more power gain and the carbs don't over fuel pretty simple. If you have anymore troubles PM me I will send you my number we can talk on the phone and answer questions right away, good luck.

 

altoys,

Thanks for your help, but it should be good to go now after 3 weeks in the shop. They checked everything on it while they had it. But thanks again for your help.