Did the plug check and the mixture with a 90 main jet seems very lean, changed to a 98 main jet and its still lean.
Fuel consumption while I run it in is about the same as the standard 50cc engine. The bigger engine is clearly running efficiently as long as I don't use the power.
I have ordered jets up to 125 to continue tuning the carby.
So I am running it in staying to about 55km/hr with my daily commute.
I am not even starting to use the power, it runs at 55 to 60 km/hr on the speedo at about 30% throttle and accelerates up steep hills at 60km/hr to run the speedo off the clock in a bit over a house length.
Its got ample power for my daily commute in traffic, once I have the mixture sorted out its finished. My guess is I will end up with the 120 jet to get it a bit rich and see how it goes.
My plan for the aircleaner to limit the power does not seem to work, the standard aircleaner is passing plenty of air for my needs.
Getting moving from 0-20km/hr is sedate, the standard clutch with heavier (2000RPM) spring does not get the engine to a reasonable torque and bogs down up hill. I have ordered an adjustable racing clutch which should help with higher revs and more clutch slip when needed.
So far I have used about 3.5 gram roller with a +30% contra spring to get the engine on the bottom of the power band for comfortable acceleration (guess is its running at about 5000RPM) with the transmission running out at 50km/hr and the engine free reving over about 55km/hr. I've had the belt slip once or twice under heavy acceleration but the transmission seems ok as is.
It feels like speeds over 80km/hr would be easily achieved but the chassis is not that good. Once the engine is run in and tuned, I will find out its top speed with a GPS just so I know what it can do.
2001 Yamaha Zuma, DR Evo 68 cylinder, Leo Vince TT derestricted, Delorto 17.5 (#98 jet), standard aircleaner, RMS fan, Race CDI, Standard oiler and premix @ 75:1 Shell SX2, Doppler SR3 variator, RMS clutch, RMS R rear shock absorber and Pirelli SL26 tyres.