the V1 is a great motor, but lets start by not modding. first make sure what you have is working at top performance. clean the carb completely and get a new float needle, decarbon the head, piston top, and exhaust/exhaust port, new plug (NGK B7HS). make sure your tank isnt rusty and going to clog things up, clean out the petcock and fuel screen,
next the biggest and most overlooked thing on the V1 that will REALLY improve its performance, the best kept secret for this engine, the big whammy....
clean and gap your points! yes thats all thats it. that ALONE makes a HUGE difference in how it runs! clean and gap them correctly and run a slightly larger than stock plug gap and you'll get a nice gain that costs next to nothing.
get it running 110% and then go about modding. you might be pleased with how runs when you're done.