I recently bought a 5000 plus at an auction , The bar cover needed repair and kill switch and wire needed some fixen. I got it all cleaned out and repairs complete the other night and dressed the bar and found a new stihl 63 gauge 325 pitch that fit well. When I put it on, the chain would hang up when I tensioned it and tightned the bar nuts.I originally thought the sprocket looked ok but concluded it was the cause. No sprocket in .325 fit that I have so I tried a new 18" 3/8 pitch Husky bar,new chain, and what looked to be a very good sprocket in 3/8 and it did the same. 2 am. so I give up for the night and it is still on my bench. I am a little tossed on which bar I will put on,Probably the 18 inch 3/8,being the sprocket on the nose of the 16 does'nt look that good. On the other hand after I try it out well I will probably sell it and have considerly more $ in the bar, chain ,sprocket combo. I think it will have enough power to pull the 18" if it has near the power of an 026 which I assume it does.