rough numbers but I measured to as well as I could:
had an 155 cylinder on an e50 with 175 deg exhaust, widened & ovalled about 2mm each side. 25 blowdown 150 intake. piston matched & modded to meet ports, transfers cleaned matched and opened, intake opening to 17mm. matched porting to to e50 bottom end, 16deg BTDC timing, 17/45 gearing. I drilled out the clutch bell, starter plate, and arms myself on a cheap drill press. About 42g off the bell, 36 off the starter. Drilled the clutch took 10g off each arm and 2 turns out from tight. Blaster pipe (not really available anymore). It was almost 50 on 50cc. like really close. Realistic tops were mid 40s but I could get it to peak out at 48. I never tried regearing but it probably wouldn't pull it. still, that was the best porting I've done on an e50, I've tried a few smaller more conservative port jobs that worked OK, and another I copied this pretty closely with a stock open port aluminum cylinder and it was fantastic.
Another I went maybe too far, I'd gone a little over 3mm up and 3 out on each side, hogged out the transfers on the jug & case, intake down 2mm inside and widened out and matched to the 15 bing intake, had to cut piston skirt to match at tdc. 15x42, 15 bing, technigas next R and that screamed but got awful mileage. it was fast.
whatever way you go tho, your takeoff sucks and you gotta get real aggressive with the clutch to engage super late