Old Thread, but for goofing around I just modded a $60 ebay Ryobi 46 cc. It had a dirty carb, and heavy carbon caked on the piston crown and top of the cylinder. No scoring or transfer and Cleaned up well
Widened the ports 6mm, I do not mess with timing as much as Chris-PA other than cleaning up the bottom of the ports. Cleand up transfers and impulse. Modded the muffler by removing the CAT material and punched a hole out the bottom. I ran another out the top circumventing the baffle. I screwed a patch over the bottom hole while I test the hole cirmventing the baffle. I will reverse and test the other. Most if not all of the gains were probably from the muffler mod. I think it would be a solid firewood saw. Longevity? as a bare piston and cyl.
It revs free with better throttle response. It does not seem to be as strong as a 4620 AV Poulan Pro I modded, but it starts easier and cuts well. I mostly run old Poulans 3400/3700/4200, Along with my newer Makita 6400 and Ryobi 10532. I gave the 4620 AV away and missed having something lightweight that could pull 18" .325. My old beasts get heavier as I grow older....as a matter of fact, I get heavier as I get older
Not much of photographer, sorry for the poor pics. I have a video somewhere of it in wood, not sure it is worth the bandwidth....but it cut
well