Question about 2010 Yamaha yBR 125
After standing in full sun, it fires and starts briefly then stops. Extra throttle does no good. Had service recently. I have never cleaned the spark plug. Seems that engine is flooding with auto choke possibly so re-starting fails. I leave it for about 10 minutes (still parked in full sun though) and come back to it and it starts. What could possibly be wrong? I don't want to just go and pay for a new fuel pump after reading older models have resolved their starting problems. Many thanks, Mary
Hi, Mary and the usual suspects are:
1. Dirt or other foreign matter between float valve and its seat.
2. Float valve sticking.
3. Float valve and/or valve seat is worn or damaged.
4. Float misadjusted.
5. Float cracked, leaky or damaged.
6. Excessive "PUMPING" of hand throttle grip.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
Yamaha YBR125 2007 Won start in hot weather otherwise fine
Yamaha YBR125ED 2005 Service Manual
OEM parts for Yamaha
Yamaha YBR125ED Owner Manual
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Posted on Feb 13, 2017
SOURCE: 1989 tw200 yamaha won't start
G'day egdbcs . Ok.now lets see.You say good spark,so i'm presuming you are doing the old sight test.Try bending the arm on a know good sparkplug about 5-6mm,earth the plug and kick'er in the guts(crank it over)Be very carefull , high voltage danger.If there's still a good spark it's safe to say that there will also be a good spark under pressure in the combustion chamber,speaking of which you should also do a compression test,anything over 100psi should be ok. as i'm not to sure of the extent of the re-build,hopefully the valves were lapped and checked for straight and true and valve seals replaced,if you notice oil on the tip of the spark plug you could have a leaking valve seal or oil seal .Try putting a small amount of fuel directly into the combustion chamber ,tighten up the spark plug ,install the plug cap and.......Yeah ..You guessed it ..."kicker in the guts".If all the abouve are correct and true it should fire up.If it runs for 5-10 seconds then stops you've got some sort of fuel starvation problem , could be dirt in the carb,blocked idle jet ,or air passage or even the needle could have come off it's clip,believe me with an old bike like yours anything could be worn and loose inside that carby.The only other thing to consider is the timing.There may be a good spark but is it happening at the right time inside the engine???. I'll leave it all in your capable hands EGDBCS.Hope this helps to solving your worries. Chow for now......Tilleydog..
Posted on Jun 03, 2009
I have been working on my carb today,the pipe from the bottom of the carb should just run down by the bottom of the swinging arm,there should be another pipe from the pipe on the left side of the carb just above the fuel intake which also runs down to the swinging arm and connect to nothing.
Posted on May 30, 2009
More likely too much air - runaway revs is indicative of too lean, not too rich. Regardless, it is your carbs causing the problem - strip them down and look - for peace of mind on an 82 bike, I would throw a rebuild kit at them.
Posted on Jun 29, 2009
Remove the fuel tank , side covers , and seat. Take your carburetor off , clean and inspect it. Check the carburetor top diaphragm. Make sure all the jets are in place and the passageways through the body are clear as well as the jets are clear. Squirt carburetor cleaning fluid through them. Most of all inspect the intake boot for rips tears and separation. Make sure your mixture screw is set to 2 full turns. Reassemble and your problem should be solved.
Posted on Oct 15, 2010
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