Question about 2010 Yamaha yBR 125

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Not starting hi. I have changed the fuel pump and the fuel injecter. however no fuel is reaching the spark plug, so wont start. can you help please. paul

Posted by Anonymous on


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Hi, Anonymous and the usual suspects are:
1. Fuel tank empty.
2. Fuel supply valve/petcock turned off.
3. Fouled spark plugs.
4. Engine flooded as a result of overuse of the enricher.
5. Vacuum hose to the fuel supply valve/petcock disconnected, broken, cracked, or pinched.
6. Fuel valve/petcock or filter clogged.
7. Fuel line to carburetor or throttle body pinched or kinked.
8. Carburetor float stuck.
9. Fuel injectors clogged.
10. Severely discharged or damaged battery, you need 12.5 volts or better and be able to pass a load test if necessary.
11. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
12. Loose or corroded wire connection at the coil, battery or plug between ignition sensor and CDI box.
Spark plug cables in bad condition and shorting check for leakage in the dark, cable connections loose, or connected to the wrong cylinders.
13. Ignition timing incorrect due to a faulty MAP, CKP, O2, TPS, sensors.
14. Faulty neutral, clutch lever, or kickstand safety switch.
15. Faulty fuel pump or fuse or relay.
16. Faulty CDI box.
17. A stuck bent or burnt valve.
18. Tip over sensor needs a reset.
19. Check for engine trouble codes.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Yamaha YBR 125 will not start
Yamaha YBR 125 Turning over but not starting HELP
Yamaha YBR125ED 2005 Service Manual
OEM parts for Yamaha
YAMAHA YBR125ED Owner Manual

Posted on Nov 21, 2016


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Posted on Jan 02, 2017

  • 91 Answers

SOURCE: wont accelarate

you didnt say if the bike sat up for a while, if it has you have stopped up carbs the bike will run with the choke on but shut off when the choke is off says no fuel going thru the low speed jets clean them by taking the float bowls off and blowing them out with high pressure air

Posted on Jan 04, 2009

  • 1 Answer

SOURCE: Electronic Fuel Pump

It turned out that the ignition key was faulty and it cut out my fuel pump and power to my spark plug but all other electrics worked. Tried my spare key and could hear fuel pump working pressed starter and it fired up how bizarre is that. so problem sorted.

Posted on Jan 26, 2009

  • 7 Answers

SOURCE: r1 2000 starting problems

Sound like a fuel problem.drain gas from gas tank and may have to take off the carb and clean it .If it is fuel injection they will have to be clean to.This will happon when a bike set that long

Posted on Feb 22, 2009

  • 3740 Answers

SOURCE: fzr 600 got killer spark pulls fuel valves in

This is not the news you probably want to hear but backfiring thru the carbs when you have good spark can be one of 2 things... either the valves are sticking / not closing properly due to carbon or the cam timing has shifted from the original position.

It would be best to do a compression test. You should have a minimum of 100 PSIG for an engine with major problems and up to 150 for a healthy engine. If you can not get 100 PSIG then it will be time for some serious engine service.

There is a possibility of the kill switch wire in the handle bar grip grounding under the grip to the handlebar but, since you said you have killer spark I doubt this is your problem.

Thanks for using FixYa.


Posted on Jun 10, 2010

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  • 1606 Answers


Check the spark timing.

Check fuel delivery. If it consistently runs on starter fluid then dies when that is exhausted, suspect a vacuum leak in the carburetor or intake manifold. This will keep the engine from sucking in fuel.

Posted on Mar 09, 2011

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