Forums 🚥 PiT STOP 🔧 Hyosung Technical Help My motorcycle loses power at high RPMs and full throttle. Reply To: My motorcycle loses power at high RPMs and full throttle.

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Hyosung GTR

If the revs did not change. That is good. Make sure the airbox is not leaking on top of the carbs.

I come with good news and bad news.

The bike has started, you were right, 17 mm isn’t correct. When I opened the carburetors, there was no gasoline at all, so it’s no wonder the bike wouldn’t start. I set the floats to 7 mm and checked all the vacuum lines again, and they’re not leaking anything, absolutely nothing. I also cleaned the carburetors as you suggested.

I cleaned the spark plugs as much as I could and checked the ohms with a tester for the black plug cap, HT wire, and the terminal pin.

Here are the values:

(BLACK PLUG CAP) R – 8.76K Ohm; F – 9.58K Ohm.

(HT WIRE – GROUND) R – 6.05K Ohm; F – 5.54K Ohm.

(TERMINAL PIN – GROUND) R – 0.2 Ohm; F – 0.3 Ohm.

I started the bike and it felt weird, the tachometer was acting strangely and stayed at 5000 rpm even though the bike was idling. I rode it for a while, then stopped to check what was happening: I touched the rear exhaust manifold, and it was hot, but the front one was cold. At that moment, I remembered that I hadn’t connected the terminal pin of the front cylinder coil, so I connected it on the street by reaching between the radiator and the cylinder, and the bike started running smoothly again. However, the tachometer still didn’t work properly. I think I might have damaged the tachometer because it still does the initial check, but when I start it, it doesn’t show the rpm, it stays at 0.

The idle is bad (like before), and I still don’t have power at high RPMs. It doesn’t go over 110 km/h at full throttle in fifth gear (it still has the transmission from the 125cc). The fuel filter is still almost empty.

I don’t know what else I can do. Should I give up?

PS: I’m going to attach a video that I recorded before this adventure so you can see what the idle of the bike looks like.