Author Topic: Sym Symphony SR125, Revs Fluctuate when throttle open  (Read 242 times)

GKK

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Sym Symphony SR125, Revs Fluctuate when throttle open
« on: January 19, 2021, 02:23:03 PM »
Hello,

Bike in question:
Sym Symphony SR125
2012
According to the speedo it has 17600 miles on it.

So I have problem with my scooter.
When holding the throttle wide open, the engine revs up and down constantly.
I have checked everything! Cleaned the carb, cleaned the air filter, checked the generator and the spark plug. Spark Plug is brand new.

The only thing which is not stock is the exhaust. I do not know what brand of exhaust it has, but it got a different downpipe and can to what I can see on stock images of the bike. 

I have put premium 97 octane petrol in it and it still does this.

I had to change both of the gaskets on the engine as well as to rebuild the gearbox. Changed the belt and the rollers to brand new ones.
Its also got brand new oil for the engine as well as the gearbox.

What are your opinions on this? I really want to start riding as I got my licence just for this.

Syd

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Re: Sym Symphony SR125, Revs Fluctuate when throttle open
« Reply #1 on: January 19, 2021, 10:01:06 PM »
You're moving when you go WOT (Wide Open Throttle)?

Tromper

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Re: Sym Symphony SR125, Revs Fluctuate when throttle open
« Reply #2 on: January 20, 2021, 12:28:09 PM »
Clutch?  Contra Spring maybe? Belt?
Does it do this in the flats, or only when climbing?
08 SYM HD200
07 Suzuki Burgman 650

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