Power loss Lexmoto zsx 125

[Guest]

My better half took my bike to work one day last week and when I went out on it later that day, it seemed to be down on power. Gets to about 1/2 - 3/4 throttle, then stutters a little, but then struggles to get to 60. Not that it goes much beyond that mind you lol. It was serviced last week, carb inspected, air filter cleaned.

The only thing I noticed was she'd put some fuel in and not closed the cap properly.

What sort of things should I be checking?

[eastanglianbiker]

did you have a lot of rain inbetween her filling up and you finding out the cap wasnt shut it might of got water in the fuel

[Guest]

No. It was a nice day.

[Tango]

Check the plug....see what colour it is....and also if it's in OK.

Plenty of oil in the engine?.......sump plugs can fall out after a service......

Valve clearances?......are they OK.

Just a few things that have sprung to mind.......

[Guest]

thanks will check those next.

[Guest]

Spark plug grey?

[acting_strange]

Spark plug grey?

 

Running lean you must be getting air in somewhere....

[fredc]

does the tank smell of diesel

[Mr Fro]

does the tank smell of diesel

Good point!

[Guest]

Not really sure how to test where air is coming from, however, whilst checking over the bike, I noticed the inline fuel filter is not full. Shouldn't this always be full? Could it be that enough fuel is getting through except when throttle is fully open, which is why its stuttering?

[eastanglianbiker]

spray some wd 40 round the front of the carb and inlet rubber wile engine is running if the revs increase then you have got air being drawn in and will need to fix by replacing the inlet rubber or tightening the carb grip screw

[Guest]

There was a big hole in the emission valve pipe. Apparently plastic is no good for high temperatures (!!) Temporary fix done by local genius and part ordered.