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Author Topic: YZ125 cutting out  (Read 2334 times)

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Offline tussock

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YZ125 cutting out
« on: December 10, 2013, 10:05:36 AM »
Hi, my yz125 2000 runs perfectly at low revs and into the mid range but when I rev it right out it cuts out. It still accelerates but it's like the spark stops and restarts 3 times a second. Has new plug, clean air filter etc etc.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline eprovenzano

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YZ125 cutting out
« Reply #1 on: December 10, 2013, 01:08:14 PM »
Hi, my yz125 2000 runs perfectly at low revs and into the mid range but when I rev it right out it cuts out. It still accelerates but it's like the spark stops and restarts 3 times a second. Has new plug, clean air filter etc etc.

Well to diagnose we need some more details.  If this a new to you bike?  Has it always done it, so did it just start recently.  Has the weather changed in your area, and have you changed anything on the bike?

The reason I ask is it sounds as though your main jet is too small or partially plugged.  To me without any more info it seems as though your bike's not getting enough fuel at full throttle.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Eric Provenzano
2019 KTM 300 XCW TPI
2000 KTM 300 EXC (Son's)
2001 KTM 380 EXC
Sold 1991 KDX 200... fun play bike
Sold 1999 KX250
Sold 1999 YZ125 (son's)
Sold 2001 Yamaha TTL 125 (son's 1st bike)
Sold but never forgotten 1974 Honda Elsinore CR250M
Sold 1974 Honda Elsinore CR125

Offline tussock

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YZ125 cutting out
« Reply #2 on: December 11, 2013, 07:57:30 AM »
It has been doing it from the day we got it (months) in all sorts of weather. It's not a surge like it's running out of fuel and no engine rattles or pinging . It's  very violent almost like a rev limiter on a four stroke. Does it have a two stage stator and the second stage has sh*t it's self ? Cheers Tussock.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline TMKIWI

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YZ125 cutting out
« Reply #3 on: December 11, 2013, 08:32:24 AM »
Stators have high and low speed windings and yes 1 or the other can fail.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
If you don't fall off you are not going hard enough

Offline gpnewhouse7

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YZ125 cutting out
« Reply #4 on: December 11, 2013, 09:11:55 AM »
Check that the power valve is installed correctly a friend of mine once bought a cr 250 that did the same thing, plenty of low and mid but went really flat on top and could be out dragged by 125's. He went through almost the whole bike before he realized the power valve was upside down, ran a lot better once that was sorted.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Redski-jr

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YZ125 cutting out
« Reply #5 on: December 11, 2013, 06:38:31 PM »
The problem could also be caused by a sticky reedvalve I think,
Friend of mine had his bike running good when stationary, but when hitting the gas it started to run very bad, replaced the reed --> problem solved
« Last Edit: December 31, 1969, 04:00:00 PM by ' »