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Guys, I'm pretty sure the carb is sorted. Didn't use any new parts, because I'm cheap and it looked pretty good to start with. Jets are clean, float works. ....but the Fantic still won't run reliably. Really looks like an ignition problem now. It starts when cold, runs OK with the occassional hiccup and then suddenly dies after riding for 5 minutes never to start up again. Obviously at that point you keep kicking like a maniac, drown the thing, kick some more, slide off the tired kick starter, sprain your ankle and utter very, very naughty words. I can feel the gods of Italian motorcycles mocking me. Ha! Joke's on them, I've had a Cagiva with electronic injection and numerous other crappy 80s and 90s motorcycles. And these days I have access to a proper motorcycle workshop with lifts and heating and tools and compressed air........so bring it on. Ignition troubleshooting mode.....ENGAGE!! When I spin up the crank with an electric drill the spark looks weak and irregular, like it skips every 8 rotations or so. When I hook up the multimeter to the leads from the stator these are the values. Mind you, resistance is measured statically and voltage is measured while running the crank with an electric drill. Brown - Red 5.0v (ac) and 111 ohm Brown - White 5.6v (ac) and 0.6 ohm Brown - Green 49.5v (ac) and 372 ohm Lacking a proper manual...am I doing this correctly? Do these values look familiar? I've tried pulling the flywheel to figure out what is what but it's some exotic size I don't have lying around like 32.
Thanks for the advice guys. Rob from Eurocarb provided me with these data: We have 2 listings for the 307:- Trial 307 89/90 PHBH26CS 60 Slide 9477.74 X74 Needle 13270.274EG Atomiser/Needle jet 6413.135 Main jet 12530.36 Idle jet 7746.70 Choke/starter jet 8649.270 Float valve 9010.2 6.5Gr floats Trial 307 89 -French market PHBH26CS 60 Slide 9477.61 X61 Needle 13270.274EG Atomiser/Needle jet 6413.135 Main jet 12530.38 Idle jet 7746.70 Choke/starter jet 8649.270 Float valve I will take the carb apart and have a more thorough look.
Hi there, can anyone give me a base line jetting for a Fantic 307 at sea level? Full story: I've just gotten my first trials bike, a Fantic 307. It starts but it runs very irregularly, won't idle properly and finally bogs down. Compression gets up to 11 bar in 304 kicks, so that seems solid. Reed valves and intake boots look OK. I've changed the spark plug (the old one was at 0.4mm gap..?), the air filter and the air box cover rubbers. Carb and jets looked clean enough, but it's time to have a second look at the carb. I suspect the float level is all over the place. The jetting seems weird as well, so I'd like to restore everything to stock.