ORIGINAL: poco242

The Toro (Gt25) we did took a ton of work. We increased intake, exahust and transfer ports. We advanced the port timing on the exahust and increased the duration on the intake. We increased and smoothed the transfer ports. The squish band was allready so close there was nothing to do there. Remove the gasket and the piston would hit the top. It was that tight allready. That engine needed a lot of work to get the power, but the end result was very positive. The engine quality was very high so it was well worth it.

Yes any engine can bennifit from little things like smoothing the ports. It is well worth it on your own engine. Just in production it is too time consuming to do. The Toro was the engine we did the most to. Other engines like the 40 allready have huge ports. There is no gain to be had there. Smoothing them may help some. I have found that getting an engine ballanced well will pick up a few hundered RPM. Ballance is very important in these little engines. There is more power to be made there than polishing the ports. Id does depend on the engine though. Some are ballanced well to begin with. The 40 is one that is very bad stock. It is way too piston heavy.

Homelite 25's are good running little engines and can make power with some mods, but too heavy for the size. The 30cc is a better choice to convert. It is the same block, but larger displacement to make up for the weight. They are little pigs