Coughing and banging while accelerating

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robonave
ganz neu hier
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Beiträge: 4
Registriert: 2. Apr 2018, 18:02
Wohnort: Italy

Coughing and banging while accelerating

Beitragvon robonave » 5. Aug 2018, 11:03

Hello and sorry for using English but I do not know German and if the Italian to German translations of Goggle will be like the German to Italian better not to translate :D
I have a big problem with my Freewind which is driving me mad!
When I rev up the engine (approx over 4000 rpm) it starts coughing and if I go on starts banging, loosing power and revolutions too.
The problem started occasionally time ago but I could drive safely, later,some months ago it became impossible to drive safely so I decided to make some thorough maintenance.
I have dismantled the "tupperware" and: checked valve clearance, cleaned air filter, changed sparking plugs, cleaned airbox, cleaned fuel tank, unistalled fuel valve and cleaned the filter (only the big one without dismantling the valve), checked the solenoid, checked the VTV valve (anyhow the cock worked when I check it sucking air from the depressurizing pipe), checked the throttle position sensor, checked sparking plugs for working, taken the carburettor to mechanic for complete overhaul. Nothing changed. From there I have tried every thing that I know could have effects on the problem.
Exchanged fuel tank, muffler, CDI unit with ones from another Suzy, completely changed all the depressurizing circuit components, changed the TPS, taken to desperation I have even bought and older carb, overhauled and installed with same results! I really do not know what to do else. The only beneficial maintenance has been the valve clearance set to the lower limits indicated by the service manual. Now the engine stands high revs for little time (better than at the beginning) but as soon as it warm up banging and coughing began. From what I know the engine is working lean for some reason (checked sparks which looks white...) but I do not know how to enrich mixture without changing the jets.
Questions:
- can, the fuel flow from the cock valve, be insufficent?(using PRI position or starter do not change situation)
- changig the jet to bigger one can be the solution? (now is standard 115 jets if some elf did not change them overnight...which I can even belive true now!!! :D )
Thanks for helping! Belive me I have spent big money till know and I am getting crazy after this bike, on the other side I love this bike: she worked perfectly and with good performance till problem beginning.
Bye

Ernesto