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Cut-Out Problem
Hello everyone. I have had this problem for a while but never sought to resolve it as It does not happen that often. My bike is Derbi 125cc, with an air cooled four-stroke Yamaha engine. The petrol tank holds 8 Litres with a reserve of 1.5 Litres. Now when the bike uses about 3.5 litres something strange begins to happen:
1) I twist the throttle and have a delayed response. 2) The bike jerks so I knock down the gears. 3) The bike continues to jerk and loose power until it cuts out. 4) It takes a while to start it again. Sometimes I choke the bike and it recovers. I have wondered about this, is it the petrol? Battery? It seems to happen after its been raining, when its cold or really warm but this is not exclusive. Spark plug is OK, air filter is OK, engine oil is OK, chain is OK, throttle cable is OK. As I said not really a massive issue for me, as 3.5 litres can take me 80 miles. Any help/advice ot there? P.s. hope you all had a good weekend in Dent, I froze my a**e off on top of holme moss. |
must be fuel problem
Filter in the petcock clean? Any other filters, fi. in the carburettor?
Must be the issue, since you are sure it is only after using 3.5 litres. Auke |
while the petrol is going out of the tank , air has to com in . otherwise you create unterpresure in the tank and the petrol stops flowing . for tad reasen the fuelcap has a smal hole . if the problem starts , open the fuelcap . if it is beter after thad ,then you have fond the problem
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sounds about right...
thanks samson, that makes a lot of sense. il give it a go next time it happens. cant see it being the pet cock valve or carb filter (not sure if i have one of those) auke but il bear it in mind, thanks.
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Keep the forum informed as to the progress you make and good luck. |
Hi Tommy
I had the exact same thing with mine, and it did turn out to be the breather hole in the fuel cap. On mine it breathes through the lock barrel, so of course over time this fills up with tiny bits of key/lock/dust/grit you name it. I found this solution on a Spanish Derbi forum, so it's obviously something fairly common. I soaked the whole lot in petrol and general prodded, brushed, blew up and down it. And no more problems. For a while after I stuck tape over the key hole, but now I don't bother and I'll just clean it out as and when. Give it a try first, it's the simplest place to start. |
Thanks dave, if it comes to a strip down Il let you know but looks like Alex is on the money. Il give it a wash tomorrow and have a go. Makes sense too as a lot of crap will get in after its been raining.
Cheers guys, I feel a bit happier now, no, a LOT happier :thumbup1: (positive thinking n all that) |
cut out.
Hiya bud.
Did a repair on one of these a while back and it turned out to be a dodgy fuel vacuum tap, just in case it's not your breather on your filler cap. All the best. Dave. |
cheers rob. latest news, I did what Alex said. There was a small hole at the top of the filler cap that led to knowhere, i couldnt even get a needle into it. The lock itself is covered with a flap so next time it starts to happen Il open the flap. I cleaned with petrol all around, this must have loosened the low grade glue that held the outer ring onto the fuel cover as it then fell off. got my UHU stick out and fixed, fingers crossed.
tom, very light headed at the moment and feels a bit sick :D |
oh wait...
...nope, the culprit is a dirty pitcock valve! wont even run on the 'on' position has to be on reserve. strip down this weekend (not me, the bike...terrible joke) and we shall have a look see. :rolleyes2:
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Keep on sniffing that petrol and glue!!!
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if anyone cares...
...dum dum duuuummmm...it was the starter motor all along!!! the swine :stormy:
on the plus side im now first hand when it comes to bump starting a bike. lets hope its just a nest of spiders clogging the brushes or some solidified oil (straws and grasping, I kno, I kno...) At least II get to spend tmrw morning looking at shiney new motorbikes at scooter crazy in huddersfield, tis the season after all :clap: |
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I had exactly the same problem with my 4 stroke 125c bike a while back. Exactly as you descibed your cut out. The breather hole sounded like the correct diagnoses.
My bike has not cut out again yet. Like Dave said the starter motor is a different problem and would not cause your bike to stall while running. Happy riding ... |
Just got the report, its the battery thats buggered. Turns out the spark plug was "too high" (I presume the electrodes had moved apart) and its drawn too much power from the battery. The cut out is fuel related, dirty pit cock valve but I can live with that. Getting it back on friday.
Your quite right Dave, the bike wouldnt start at all yesterday and thats a different problem to the cut out. Essentially I fixed the cut out when I ran it on reserve. The starter motor ticked over less and less when I tryed yesterday, until it didnt move at all. This is becasue the battery is boobed up due to not looking after my spark plug. Apperently motorcycles need "regular servicing" :blushing:....... |
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