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yamaha SR125 cuatome start problems


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If anyone has any ideas fire away starts on bump but not button runs and rides but cuts out when i stop so far carb cleaned new plug oil changed tappets set (not perfect no feelers) timeings lined up fine ima slightly lost its slowly got worse since my daughter dropped it

Any help much appreciated its my only.transport sorry if this is a repost

Right, bit of basics first.

what did you do to the tappets? and why did you need to do it? was the engine at Top dead center when you done the tappets? and did you take the cam shaft out?

If the motor wasn't at TDC and you moved some thing then the timing will be out and she wont run right at all.

The air screws are "normally" either 1.5 turns or 2.5 turns so start at 1 and work up till she feels / sounds like she is running better.

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So you got a spark,

You got a good strong battery.

You got fuel in the tank.

Do these Sr's have a fuel pump? if so is that working and priming the carb?

is the float bowl on the carb filling up with fuel?

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No fuel pump yes fuel is gettin there as ive said she tries to go off button.but just hasnt got that little extra umph exhaust and head both get warm

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Have you tried jumping her with a car battery?

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really awkward with tools i have thats your mix andrew mines set to 1.5 out carb has to come off lol its really starting to seem like a compresion issue but cant seem to find where not rings no smoke at all from her

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The only way I can get to it without removing is with a quarter inch socket driver bit and a pair of pliers!

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A car battery has more cranking amps and will help fire it up with out having to bump it.

I know you may have said it before but right before you played with the tappets etc what exactly was the bike doing for you to do the work? just trying to get a clear picture of what could have gone wrong as it seams like its all down to the carbs not getting enough fuel in the cylinder.

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slightly obviously to bump it

Not sure but that sounded a bit sarcastic - the guy has a SR and is trying to help.

If the bike starts on a bump but not the button the extra suction from the engine may be greater sucking the fuel in to ignite. A more powerful battery test (car battery) may turn the bike over faster creating the same effect.

Before you do anything else;

Open the fuel cap and see if it starts with it open

Check the fuel flow by taking the fuel hose off the carb to see if the fuel flows

Try jumping it with a car battery

Make sure that the tappets are set correctly. Next I would check the carb. - again if you had to.

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started when i came to work friday left friday to go home wouldnt start just turned engine over it tries to fire but wont go that little extra to fire so i thought first cheapest thing buy a new plug new plug in and still the same so asked the guy at the shop he helped me bump it and said seems low on compresion so to set tappets so did that and still no luck so cleaned carb still same i thought at that point mabe a blocked oil filter or crappy oil so replaced them and did oil change still nothing :(

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Have you tried putting a small amount of fuel in the plug hole before using the button?

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Not sure but that sounded a bit sarcastic - the guy has a SR and is trying to help.

If the bike starts on a bump but not the button the extra suction from the engine may be greater sucking the fuel in to ignite. A more powerful battery test (car battery) may turn the bike over faster creating the same effect.

Before you do anything else;

Open the fuel cap and see if it starts with it open

Check the fuel flow by taking the fuel hose off the carb to see if the fuel flows

Try jumping it with a car battery

Make sure that the tappets are set correctly. Next I would check the carb. - again if you had to.

was not sarcastic sorry if it sounded that way my grammer sucks :(

never thought to try with fuel tank open but put a full tank of clean fresh fuel in today as i thought mabe a dud batch as it happens some times.

fuel flow is fine tried that.

the jump from a car is my next test but at work while 8:30 all week :(

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