125cc engine locking back wheel up - Help

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125cc engine locking back wheel up - Help

Hello All, first post!

Need some experienced biker help with my KSR Moto GRS 125cc bike.

I start up and warm up the bike with the choke out and set off - everything OK -

2 minutes down the road there feels like friction on my back wheel, slowing down the bike, almost like I am braking. The revs on the engine start to slow down slowly even at full throttle. At the same time the back wheel will not turn at all and starts locking up. I sit at the side of the road for 2 mins with the choke out. I rock the bike back and forth after a while until the wheel freely moves again.

I can now continue down on my way, although with the choke slightly on, as when the revs drop below 4k when I twist the throttle it jerks the bike forward before engaging.

Anyway, I am wondering if anyone has a clue what could be going on. I have ridden bikes for a while now and I am completely perplexed!

Thanks in advance,

J

125cc engine locking back wheel up - Help

First thing to check is whether it's a problem with the engine, or a problem with the back brake. When the bike comes to a halt, put it into neutral. If you can now turn the back wheel then it's a problem with the engine, if not then it's a problem with the back brake.

If the brake is dragging then it can quickly over-heat and seize onto the disc. On a small capacity bike this can overpower the engine.

If it's the engine then it sounds like it's partially seizing! Very unusual on a 4-stroke.

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