YBR125 engine power loss

[Will0104]

Hi all, i have a problem with my Ybr125

Had this problem awhile now and used to only occur a few times a month but its getting much more regular.

Basically what happens is, i will be going along (speed doesn't seem to affect it, happens at any speed) and all of a sudden i loose all bike power. It feels as if the engine has been muffled in a sense, it still is sort of going but as if it has been put in slow motion. Sometimes it just goes back to normal either after a few seconds or a gear change, or sometimes i have to stop and the engine fully stops and i have to restart the engine.

It only seems to happen near the beginning of a ride, after 10 or so mins i have never had it happen.

Anyone have any ideas what it could be? thanks in a advance,

Will

[RantMachine]

Does it have oil in it?

[Fozzie]

Possibly a problem coil. Quite a typical Yamaha thing to go and can start off as an intermittent fault like you describe.

It sounds electrical to me. Luckily parts are cheap and Phil Young on here has access to his old stolen YBR so you might be able to pinch his if you offer some gold coin

After that I'd check the earths on the bike and look for shorts. I had similar on an SV and it turned out that a wire had rubbed through and was touching the frame. It took a while to figure out as it was under the seat and when I was sitting on the bike I could cause it to short or push it out of the way. So it would often die when I'd just started it and set off, but then mysteriously work again when I got off, got back on and tried again.

[Guest]

I don't have a spare coil but this was my first thought as well.

My girlfriend has had 2 coil failures so I certainly would either test it or get a second hand YBR one for a tenna.

Also had the exact issue fozzie mentioned in my YBR. I thought it was a possible fuel issue and when I checked my negative terminal it was loose so that would give power issues and hard starting symptoms as well.