Yamaha YBR125 2007 Won't start in hot weather otherwise fine

[rwebley81]

Hello everyone,

I have a Fuel injected 07 YBR 125. It's been working fine all the way through the winter without so much as a blip and now the weather has warmed up it's stopped working..

It will start and run fine in the morning when the ambient temperature is cool but when I want to come home in the warmth of the afternoon it won't start.

It turns over and I've tried to check that there is fuel reaching the injector through the fuel pipe. I've noticed that the fuel pump doesn't whirr when I turn the ignition on but yet it does in the morning when it's cold.

I think this might be the problem.
What that is heat related is stopping my fuel pump working?

Any help would be great.

Thanks

Richard

[.]

heat related = temperature sensor ??

does the yellow coloured system check light come on remain on for about 3 seconds or does it flash indicating a fault?

have you checked all the wire connections, especially the bunch located to the left of the carb?

[rwebley81]

I know how annoying it is when you only find people with similar problems and no solutions.

I fixed the hot starting problem on my YBR 125. The fuel pump wasn't whirring and priming fuel when it was hot.

I got a wiring diagram and a multimeter and checked all the electrical connections and that the fuel pump was getting an electrical signal from the ECU when a turned the ignition key, everything was fine.

I concluded that the problem was with the fuel pump. The fuel pump is a sealed unit. I bought a second hand fuel pump for £40 off eBay, replaced the fuel pump and fixed the problem.

[la_bigmac]

Thanks for posting this, it came out top of a Google search for "YBR 125 2007 fuel pump".

I rode into work this morning with no problems, just went to pop out at lunch having left the bike in the sun for 5 hours. Turns over but does not start, not even a flicker of life.

When the ignition is turned on the fuel pump does not prime as it would normally.

The orange light comes on, for 5 seconds then goes out (as per normal) no indication of anything wrong.

I moved the bike into the shade for 30 minutes. Started first time. Other stories on the web involved throwing a bucket of water over the bike!

What was the model number of the fuel pump you brought? I am wondering if it was newer then the original or a second edition or something?
Regards,
Mat.

[rwebley81]

Hi Mat,

Sorry I can't help with the model number at the fuel pump. I've since sold the YBR and bought an SV650.

This seems to be a problem that other people have had. Maybe Yamaha should have a look at what is wrong with the fuel pump when it heats up

[Mark65]

Hi
I have an 07 YBR just crossed 14200 miles, never had a problem with starting in hot or cold weather.

Mark
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07 Yamaha YBR125, 07 Honda CG125 , 15 CBR300R (Chocolate Crank, Deaded), 16 CB500FA, 19 Honda Forza 300, 70 Suzuki SV650

[jonnyrider]

I have the same problem I think... Failed me at a T-Junction yesterday after being out in the sun for a few hours and then would not start until the cold light of day this morning... Now it is idling really rough.

I am so frustrated because it doesn't really fill me with confidence and I like pottering round the country lanes and I really could do without breaking down in the middle of nowhere despite my RAC cover!!

Have we pretty much concluded that the integrated fuel pump/filter doesn't like being hot and just gives up? The weird thing with mine is that you can hear the pump whirring on ignition key so I can't imagine the pump is faulty in that sense....

key on

fuel pump whirrs

orange engine lamp for 3/4 secs

turn over

starts for like 2 seconds and then cuts out

refuses to even start again

Does anyone reckon it'd be worth me emptying the fuel tank and cleaning the lines/filter etc? Maybe there's just some shit in there that is stopping petrol getting down to the injectors? The fuel pump assy is £300 new from Yamaha and there aint any on ebay atm!

Any suggestions!?
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Yamaha YBR 125 (2008)

[dj2121]

but i don't understand is that even possible in r125,,
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Yamaha freak

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[dj2121]

Hahaa....., like u got offended
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Yamaha freak