CB125F 2017 tickover issues

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Godspeed
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Re: CB125F 2017 tickover issues

Post by Godspeed » Thu Jan 07, 2021 6:46 am

Again I know this was the cbf125 so not the same model, but I had to change my ecu as it was leaning the mixture too much when warm. Secondhand ones can be picked up for near £20... maybe worth a try?
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Re: CB125F 2017 tickover issues

Post by Hoggyf » Thu Jan 07, 2021 8:40 am

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Again I know this was the cbf125 so not the same model, but I had to change my ecu as it was leaning the mixture too much when warm. Secondhand ones can be picked up for near £20... maybe worth a try?
Thankfully parts are cheap and I should be able to recover some money from the parts I have fitted then removed, I've an oil sensor and lambda probe on order now, I'll try that then go for an ECU but I need to speak to Honda about the ECU - in case its linked to the ignition??? Wish it had a carb, cleaning or preplacing a pilot jet is a damn sight easier :D
Then:
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Re: CB125F 2017 tickover issues

Post by Hoggyf » Sun Jan 10, 2021 12:16 pm

The saga continues, replacement oil sensor and lambda probe made no change, however I did a test with it running with the spare oil sensor connected but not in the engine so it was seeing cold oil all the time and it sits fine st about 200rpm, switch it over to the oil sensor in the engine that's hot and it immediately dies, turn it off and back on still dies, connect it back up to the cold one and its fine again, so my assumption now is having changed everything else that it must be the ecu.

Anyone know if the ecu on this would be linked to the ignition coding wise? Or can I replace the cu without having to replace the ignition set?
Then:
Honda MB5, Honda MBX125, 350LC, RGV250, MTX125, GasGas JTX250, CM 644 DS, BMW R1100S, Beta Rev3 250, Beta Rev4T, Honda XL700V Transalp, BMW F800 GS, Kawasaki Super Sherpa
Now:
Montesa 4RT, Triumph Tiger 800, Beta Alp, Montesa 315

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Re: CB125F 2017 tickover issues

Post by Richard Simpson Mark II » Sun Jan 10, 2021 12:21 pm

I'd just tuck the 'old' sensor out of the way on the bike somewhere with the wires attached.

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Re: CB125F 2017 tickover issues

Post by Hoggyf » Sun Jan 10, 2021 12:58 pm

Tempted to do that but I'd like to resolve this plus it's being sold and I'd rather sell it honestly than bodge it, luckily the parts are cheap second hand
Then:
Honda MB5, Honda MBX125, 350LC, RGV250, MTX125, GasGas JTX250, CM 644 DS, BMW R1100S, Beta Rev3 250, Beta Rev4T, Honda XL700V Transalp, BMW F800 GS, Kawasaki Super Sherpa
Now:
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Re: CB125F 2017 tickover issues

Post by Godspeed » Sun Jan 10, 2021 2:37 pm

No idea on the matching of the ECU to the bike, but I’ve not had that on any of my other 125s before....
Hope it works!
The Meandering Moustache

Going Big and Riding Small

Honda SH300 (too fast....)
Honda SH125 (Mini-Pad)
Honda Innova ANF125 (Adventure bike) Honda Cub C90. (Enduro bike)

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Re: CB125F 2017 tickover issues

Post by Hoggyf » Wed Jan 13, 2021 8:56 pm

It runs!!! :mrgreen:
Replaced the ecu tonight and done a couple of cold starts and several hot starts and it sits and ticks over like a Swiss watch so anyone want to buy a fuel pump, throttle body, oil temp sensor and a lambda probe for a cb125f?

Thanks for the help and advice all
Then:
Honda MB5, Honda MBX125, 350LC, RGV250, MTX125, GasGas JTX250, CM 644 DS, BMW R1100S, Beta Rev3 250, Beta Rev4T, Honda XL700V Transalp, BMW F800 GS, Kawasaki Super Sherpa
Now:
Montesa 4RT, Triumph Tiger 800, Beta Alp, Montesa 315

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Re: CB125F 2017 tickover issues

Post by Godspeed » Thu Jan 14, 2021 7:30 am

Good news. Bizarre how these things go.
It’s one of the things I love about smaller bikes that you can replace a fair few parts for relatively little.
Enjoy!
The Meandering Moustache

Going Big and Riding Small

Honda SH300 (too fast....)
Honda SH125 (Mini-Pad)
Honda Innova ANF125 (Adventure bike) Honda Cub C90. (Enduro bike)

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Re: CB125F 2017 tickover issues

Post by bill_qaz » Thu Jan 14, 2021 12:44 pm

Good news you solved it.
Keep the other spares in stock as you never know :shock:

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Re: CB125F 2017 tickover issues

Post by Hoggyf » Fri Jan 15, 2021 12:49 pm

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Keep the other spares in stock as you never know :shock:
Its getting sold!! That was why I was trying to get it sorted as its my GF's and her son was using it for school but needs a car for uni, neither of us wanted to sell it with a fault so I persevered. Would have been much easier with a carb!
Then:
Honda MB5, Honda MBX125, 350LC, RGV250, MTX125, GasGas JTX250, CM 644 DS, BMW R1100S, Beta Rev3 250, Beta Rev4T, Honda XL700V Transalp, BMW F800 GS, Kawasaki Super Sherpa
Now:
Montesa 4RT, Triumph Tiger 800, Beta Alp, Montesa 315

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