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Yamaha SR 125 starting problems

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Hello everyone,

I have a problem with my SR 125 '97 custom and i can't find it whats wrong, so I really hope that you could help me.

Let's begin with this video:

https://www.youtube.com/watch?v=V-LMRUT7IC8

Is it normal that spark shows not cyclically? But in the beginning and end when I push engine start button. What did i checked: battery is ok, changed spark plug, spark plug gap, checked ignition coil with tester one of two methods, checked pickup coil resistance, even changed CDI unit, nothing!. I don't know maybe spark cable is bad or I checked wrongly ignition coil, pickup coil resistance, source coil resistance.. I don't have an idea how to make that bike run. The best help i think would be is SR 125 owners could say do the spark shows the same way like mine do, but i really think something is wrong with mine.

Second problem, video:
https://www.youtube.com/watch?v=15HlmQh1_o0

S
trange sound when i accelerate while trying to start engine, actually is the same sound come out when the engine was running and i accelerated quickly, if i do that engine just immediately stop running. What I did: Firstly and till now i think this sound is because of bad mixture of air and fuel (petrol) that's might be one of the reasons cause till now i can't adjust air/fuel mixture well cause i have not a original air filter, and the stock parameters might be wrong. I'am talking about pilot screw (2 turns out or 720 degrees) cause custom air filter give more air then original so i think pilot screw should be screwed more than 2 turns out, PLEASE LET ME KNOW IF I"AM WRONG. Actually about this problem i have no idea what could be wrong i'am just guessing, maybe its mixture.

And last video shows how it trying to start:

https://www.youtube.com/watch?v=7jSSJE901ao

So I really hope you can help me, waiting for any advice.

Thanks

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try squirting just a little oil into the sparkplug hole, all this attempted starting will have washed the oil from the piston rings and reduced the compression...about 10cc

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I just tried your advice. Bike much more easily wants to start but when it does it runs only for couple seconds and then stops.. Any ideas? What about that strange throttle sound, maybe you know how to fix it? Any ideas about spark plug problem?

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have you had the generator flywheel off?

If so did you torque up the retaining nut/bolt properly?

This type of intermittent sparking can be caused by a loose flywheel or sheared flywheel key etc.

Another possibility is loose stator plate fixing screws have allowed the timing to slip (retarded)

if these are not the reasons then I dont know what the problem might be so check this out thoroughly.

The noise I would say is normal

What isnt normal is opening the throttle a lot when attemting to start the engine, not generally good practice!

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I am not a mechanic, as will probably be proved by this, but it wouldn't be something as simple as the timing chain tensioner thing?? Mine was a bugger to start until I adjusted mine.

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have you had the generator flywheel off?

If so did you torque up the retaining nut/bolt properly?

This type of intermittent sparking can be caused by a loose flywheel or sheared flywheel key etc.

Another possibility is loose stator plate fixing screws have allowed the timing to slip (retarded)

if these are not the reasons then I dont know what the problem might be so check this out thoroughly.

The noise I would say is normal

What isnt normal is opening the throttle a lot when attemting to start the engine, not generally good practice!

I checked the torque of flywheel bolt. It's ok it does'nt move to any direction. About stator plate fixing screws I checked them too, those are ok too. checked pickup coil and stator coil resistance it's ok. I really don't have a clue what could be wrong. I'll try to check once again ignition coil maybe there is the problem.

i know that it isint normal to open throttle a lot when trying to start the engine, but i just wanted to show what kind of sound it is.

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I am not a mechanic, as will probably be proved by this, but it wouldn't be something as simple as the timing chain tensioner thing?? Mine was a bugger to start until I adjusted mine.

Thanks for advice but tried that, didn't help out.. :/

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Hi. Sorry to revive an old thread but i have this exact same problem. Did you ever find out what was causing the sparking problem. 

Cheers

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He has never been back since post in Oct 2013 so wouldn't hold yer breath for an answer.

 

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Hi Pignapper. What have you tried so far? What are your symptoms?

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