Reply To: My motorcycle loses power at high RPMs and full throttle – Hyosung GTR
I assume as it’s a 250efi engine & yours was a carb bikes your using the carbs from the 125?
Check your float height , after every ride on my carb bike = the big filter is usually full. Or your float needles are jamming causing some internal engine slow leak of fuel in to cylinders = Your manifolds will be “wet” inside as a hint. Also open “OIL FILLER CAP” ( on the clutch cover) and sniff inside hard. ==> If you smell fuel => change oil before riding again. Can you also clean your spark plugs , go for a short ride => wait to cool down => Take pictures of spark plugs so we can see the mixture ? Simon also has the EFi 250 motor, he knows if the fuel system is too rich or too lean,. Pictures of spark plugs will help OR It could be electrical! (Coils? Stator unit?) (Since stator is also part of ignition system = high revs , more pulses to cdi , cdi talks to coils to spark the plugs. , dashboard tells you how much RPM engine is doing
Today I came back from the garage feeling defeated. The bike won’t start anymore.
Firstly, I removed the spark plugs, and they were black, indicating that the engine might have been running rich.
- I checked the float needle, and they seemed fine.
- The float height was very off. They were at 8 mm and should be at 17 mm according to the manual. I adjusted them as the manual instructed, but I didn’t check the fuel height. Is it important?
After all that, I tried to start the bike, but it wouldn’t start. When I engaged the starter, it made an attempt to start but didn’t go any further. During the starting attempt, the fuel filter only filled to about 5%.
Could this be due to the starter jet, main air jet, and the 125 slides? Because according to the manual, they are different between the 125cc and 250cc models.
I’m thinking of buying second-hand carburetors from a 250cc. I don’t know what to do.
P.S.: I opened the oil filler cap and smelled it, but it didn’t smell like gasoline.