I have the Free Spirits kit. Bought it back in 2006. Need to replace the front sprocket due to wear. Saw several folks here who have done chain conversions and they are using either the V-Twin sprocket or the PBI sprocket (277x). Local shop gave me a PBI sprocket but it turned out to be a 277 (530 pitch, not 520) so obviously it didn't work with my chain. However, even beyond that it wouldn't fit on the main shaft. Sprocket hole was too small. Also, my original sprocket from Free Spirits has a lot more back spacing. I haven't measured it but I'd say at least a 1/4 inch or more, so the sprocket would come out a lot further than the PBI sprocket. Can post some pics of each if that helps (just don't laugh when you see what happened to the Free Spirits sprocket). Would like to avoid paying $150 for the Free Spirits sprocket.