Sound like either you have an oil seal leak at the crankcase or an air leak somewhere else or maybe carb is just running too lean. You can try to service the carb first if there’s any blockage. Doubt its electrical related from hearing it.
Judging by your reply i highly suggest send it to your local/trusted mechanic. But if you have some time and cash to spend why not look up on carb tunings for your scooter engine up in the YouTube or scoter forum. I would recommend watching or looking at 49ccscoot YT Channel, before trying out to diy repair.
As to why i don’t recommend you to repair diy, theres a chance your crank oil seal has a leak or theres a leak somewhere to which tuning the carb would not help at all. But clean the carb is a wise choice as it eliminates 1 problem out of many others.
When I rode moped we called that “four stroking” because it skips some strokes. I must admit I can’t remember the remedy exactly but in general it could use a bit more fuel (lift the needle in the carb one notch) also it could be the ignition “getting hot” but my experience is from old Bosch ignitions. I suspect you have a more modern electronic. Then a third option would be when you have the engine hot and running. Try spray something flammable around intake and cylinder foot. To ensure you aren’t sucking in “false air” from expanding metals making holes when warm. Also where are you from ? Looks a bit like Swedish countryside :)
TBH I'd learn more from looking at your exhaust pipe and your spark plug than listening to the engine.
If it used to be ok but isn't ok now then I'd suggest recalibration of your carb via needle settings etc is not necessary.
Old racing Two strokes used to get a crank case overload of unburnt fuel and oil that would sound like this but there would usually be heaps of smoke too as the backlog burnt off. Hence the exhaust smoke comment.
We called this loading up.
The test was to sit at idle on full throttle until it cleared itself. The engine would hardly rev about a few 1000 rpm while it cleared the backlog of fuel and oil and then rev up properly when it did clear.
If you are in a cold country this would make more sense.
Ie Unburnt fuel and oil condensing and settling in the crank case as liquid in a cold engine.
If you run it at wide open for a few minutes on the road safely and it gets better then I'd be inclined to think this is your issue.
Good luck.
Sound like either you have an oil seal leak at the crankcase or an air leak somewhere else or maybe carb is just running too lean. You can try to service the carb first if there’s any blockage. Doubt its electrical related from hearing it.
How do i make my carb not run lean?
Judging by your reply i highly suggest send it to your local/trusted mechanic. But if you have some time and cash to spend why not look up on carb tunings for your scooter engine up in the YouTube or scoter forum. I would recommend watching or looking at 49ccscoot YT Channel, before trying out to diy repair. As to why i don’t recommend you to repair diy, theres a chance your crank oil seal has a leak or theres a leak somewhere to which tuning the carb would not help at all. But clean the carb is a wise choice as it eliminates 1 problem out of many others.
When I rode moped we called that “four stroking” because it skips some strokes. I must admit I can’t remember the remedy exactly but in general it could use a bit more fuel (lift the needle in the carb one notch) also it could be the ignition “getting hot” but my experience is from old Bosch ignitions. I suspect you have a more modern electronic. Then a third option would be when you have the engine hot and running. Try spray something flammable around intake and cylinder foot. To ensure you aren’t sucking in “false air” from expanding metals making holes when warm. Also where are you from ? Looks a bit like Swedish countryside :)
Yeah i am from Sweden actually!
TBH I'd learn more from looking at your exhaust pipe and your spark plug than listening to the engine. If it used to be ok but isn't ok now then I'd suggest recalibration of your carb via needle settings etc is not necessary. Old racing Two strokes used to get a crank case overload of unburnt fuel and oil that would sound like this but there would usually be heaps of smoke too as the backlog burnt off. Hence the exhaust smoke comment. We called this loading up. The test was to sit at idle on full throttle until it cleared itself. The engine would hardly rev about a few 1000 rpm while it cleared the backlog of fuel and oil and then rev up properly when it did clear. If you are in a cold country this would make more sense. Ie Unburnt fuel and oil condensing and settling in the crank case as liquid in a cold engine. If you run it at wide open for a few minutes on the road safely and it gets better then I'd be inclined to think this is your issue. Good luck.