Hey Wayne, the mods are funny in that most listed are not really recommended, go figure. I still havent got a handle on linking sites, but this will get you there Goggle Velosolex S3800 Carburator click on the link that has BrianSolex as the address, that gets you to the carb mod page, you can navigate to all the mods form there, great reading. Still before I built a full house race engine(LOL) I would see whats up stock wise with yours. Seems the rest are running pretty well, there must be a hidden issue you havent found yet. One thing for sure 2 strokes respond well to an increase in timing. The stock setting is supposed to be around 23degrees I think a bump to 26-28 would wake it up(the engines in general). Would require shaving the key out of the flywheel, lapping the flywheel a bit then determining the timing, probably no more that a key width. Have to get out the degree wheel. I may do this to #2. The original Solex flywheel was keyless I believe and the timing was set with it(as well as point gap). Probably need some input from people famailar with the older Solex.