Reply To: Carb Tune up – 2008 GV125 Carby
Can you get hold of a compression tester ?
Warm up the bike even with choke for 10mins max
Then remove spark plugs on both engines
Put compression tester on front engine spark plug hole => Press start to crank bike for 5 seconds maximum
Record the PSi reading from the gauge
And repeat this for the rear engine
Tell us the engine compression on both cylinders , i feel like it is best to start here first.
If the engine is compressing well above OEM specs , then it is easier to diagnose the carb next
if not , copy these instructions and have your mechanic visit your bike to do it first, and update us the results.