CBF 125 overheating in hot weather and cutting out.

[PhatPuffer]

Hello everyone,
My bike has only done this twice, once two years ago and today on my way back from work, it has been stood in the sun for almost nine hours and was perfectly fine for half my journey home when it decided to not fully rev and start to slow down after a couple of attempts it started back up so I was able to make it 100 yards down the road and stall again, luckily I stopped outside another bikers house who said the temperature sensor maybe dirty or faulty. I have cleaned it and checked it but it seems to be okay

If anyone has any other suggestions or information regarding this would be greatly appreciated.

[stinkwheel]

Did it seem very hot when you stopped? How's the oil level? Serviced recently? Did you do the oil filter? How does the sparkplug look?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[pdg]

Is fuel vapourlock still a thing that happens or is that not "2024" enough?
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Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[PhatPuffer]

[quote="stinkwheel"]Did it seem very hot when you stopped? How's the oil level? Serviced recently? Did you do the oil filter? How does the sparkplug look?[/quote]

Yes extremely hot, the oil level is topped up and serviced in April, new oil strainer and brand new sparkplug

[stinkwheel]

If it was extremely hot, it's probably not the temperature sensor then, your loss of power could well have been a partial piston seizure. That's usually due to either a lack of lubrication or the engine running lean.

Worth taking a look at the sparkplug electrode to see if it's showing signs of scorching/melting.

Not sure if those engines have a sight glass or just a dpistick for the oil level. If there's a sight glass, check the oil level in the sight glass drops when you turn over the engine to verify it's still pumping oil.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MCN]

Smells like piston seizure.

May not be easy to detect in the oil screen/filter whatever is fitted to that engine.
If seriously hot the oil would smell burned and maybe some gaskets weeped/oozed oil.

If you remove the spark plug and try to turn the engine over by hand. Top gear and rotate the back wheel.
The engine should birl over freely.
If the problem persists, it could be time to split the engine.

Or it might just be shit in the carb/fuel line causing lean burn.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.