This topic has been discussed multiple times. Likely why you are not getting much in the way of responces. One of the best answers was to look at earlier Dolmar products and how long they were supported. I have not really needed any parts for my 6100. I tried to buy a purge bulb locally and ended up waiting like 10 minutes while the guy did computer and trip to the back room and came back to tell me they did not have it in stock, the price was like $15. I looked it up myself and yes that is the price while the one for the 351/421 is three dollars and change. I was sort of expecting him to just give/sell me a generic one. I had roughed it up and ended up essentially gluing it back. I probably should get the metal piece that goes against the saw body and bar, as it has been damaged by thrown chains. It might be hard to damage the engine, I ran my high speed adjustment in just about all positions from one turn to four turns out and did not seize it. If you like the idea of a reed valve, the inboard clutch, the small spline drive with the small Husky mount it is about the only choice I am aware of. Small spline means 7 and 8 tooth .325 rims are available.