CBF125 turns over but doesn't fire - gearbox?

[xocnai]

Hi

New to the forum, but desperately searching for help diagnosing my CBF125's issue.

While riding recently, a 'rubbing' kind of sound started coming from the gearbox area (it almost sounded like a loose fanbelt would on a car). This was only happening in gears 2 and 3. Shortly afterwards, I lost all drive and the engine cut out.

Since then I have been unable to start the engine via ignition or bumping. It turns over but makes an unusual sound when doing so, again emanating from the gearbox area (I think!)

I have linked to a video that I've taken demonstrating the sound being made when turning over.

Does anyone have any ideas?

https://www.youtube.com/watch?v=iIVgzbO4X3w&feature=youtu.be

Thanks

[misscrabstick]

Borrow a compression tester gauge, remove the spark plug, attach gauge, turn engine over on the starter button, do you have a reading? I think you might not have.

[wots]

It could be the starter, missing teeth etc. The one time I tried to bump start mine I couldn't because of the FI, but I think it was because the battery was almost totally dead. If you don't have a compression tester, just take spark plug out and feel for any kind of compression. But that is just spinning, either the starter is spinning and not engaging to actually turn the engine, or there is zero compression as has been mentioned.

EDIT: Also, drop the oil and look for anything that shouldn't be there, it takes just under a litre I think.
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Currently: Yamaha DT 125 LC2,Repsol Fireblade, and Bumblebee MSX 125

[Nemo]

The gearbox won't prevent the bike from firing.

Take spark plug out and check for spark, put thumb over hole see what compression there is.

It's not the starter motor since the engine is turning over.

-Lewis
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Previously owned: Kawasaki KH125, Suzuki GP125, Suzuki GX 125, Honda CB125 TDC '83, Honda ntv 600, Kawasaki ER5, Kawasaki ZZR600, Aprilia RSV 1000 Mille
Now own: Ducati 848 evo

[wots]

[xocnai]

Thanks for all the replies so far. I don't have a compression gauge, but lack of compression has been mentioned to my elsewhere too.

Will grab a gauge in the week - if this turns out to be the case, would there be any theories on the root cause? I'm especially flummoxed by the noises that were coming through in gears 2 and 3 under drive (noise usually ceased with clutch in)

Have attempted starting with no stand, same result - not an inhibitor issue.

Also, battery is nice and charged after having had FI issues myself that were due to battery drain.

[tomh]

Do the basic tests first by checking for a spark:

Remove your spark plug using the tool in your bikes tool bag. Once removed, plug the spark plug back into the HT lead and hold the spark plug against the engine. While doing this press the starter button and you should be getting a nice blue spark.

When putting the spark plug back make sure you don't cross thread it and then tighten it by hand. It will then only need a 1/4 turn with the spark plug tool.

[xocnai]

I shall hopefully have some time this weekend to do a few of the things suggested here - thanks again and I'll let you know the outcome.

[Nemo]

When was it's last service?
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Previously owned: Kawasaki KH125, Suzuki GP125, Suzuki GX 125, Honda CB125 TDC '83, Honda ntv 600, Kawasaki ER5, Kawasaki ZZR600, Aprilia RSV 1000 Mille
Now own: Ducati 848 evo