HarborFreight sells the factory reconditioned Ryobi 31cc typically for $67, but I've been buying them at $49.95 with an ad from one of their catalogs. They go on sale every once in a while. Same goes for the Homelite 25cc - $49.95 - but I'm not too crazy about that engine. It is a bit gutless compared the the Ryobi 31cc, which is itself no big powerhouse. I'm trying a few trick in hopes of boosting power on the Ryobi - better ring, advanced ignition, raised compression, etc.

BTW, if I'd kept all the catalogs mailed to me from HarborFreight, I could probably stay warm in Alaska thru a whole winter.

Also, try to hawk the rest of the weedwacker to your local lawn mower repair shop. The Ryobi Trimmer Plus detachable lower sections seem the most welcome - another reason I prefer the Ryobi.

Currently, I'm torn between two very good candidate for conversion - Ryobi's 26cc 4cycle and 22.5cc 2cycle from their professional-grade weedies. Troy-Bilt sells a line identical to these Ryobis - including a 25cc version of the 22.5cc 2cycle. If anybody has done a conversion on any of these, I'd be very interested to know. Thanks.