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TW125 doesn't start


e30lou
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you heard this clicking when trying to bumpstart the bike?

Could it be the chain is so loose/worn it was jumping the teeth on the sprocket?

yes the clicking was whilst bumping it but it's hard to pinpoint exactly where it was coming from. Could it be the starter relay is just clicking like mad? I've got this video to show everyone what happens when I try to start it, see if it helps to see what I've been bleating on about :D

video link

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yes the clicking was whilst bumping it but it's hard to pinpoint exactly where it was coming from. Could it be the starter relay is just clicking like mad? I've got this video to show everyone what happens when I try to start it, see if it helps to see what I've been bleating on about :D

video link

From seeing the video it seems the starter motor is working just fine.

However I wonder about the compression, it seems to whizz the engine over just a little too easily. Verify there is a good oil level in the engine and try a squirt of oil in the spark plug hole (not too much...about a teaspoon full) this can restore compression if continual starting has washed away the oil from the piston. I take it there is lots of fuel available too?

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From seeing the video it seems the starter motor is working just fine.

However I wonder about the compression, it seems to whizz the engine over just a little too easily. Verify there is a good oil level in the engine and try a squirt of oil in the spark plug hole (not too much...about a teaspoon full) this can restore compression if continual starting has washed away the oil from the piston. I take it there is lots of fuel available too?

there's plenty of oil in there, just had a look but i will try the oil in the spark plug hole, see if that helps. Yes, plenty of fuel in there too

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Starter is fine

Battery seems fine

Starter relay seems fine,,no clicking

So starter is not the problem.

To me it sounds like your not getting fuel, Or you have no spark.

Are you trying to start with choke on, if you have one.

Is the plug getting wet after you try to start it. Take the plug out and have a look.

Also check all the fuses you can find, make sure there not blown.

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Starter is fine

Battery seems fine

Starter relay seems fine,,no clicking

So starter is not the problem.

To me it sounds like your not getting fuel, Or you have no spark.

Are you trying to start with choke on, if you have one.

Is the plug getting wet after you try to start it. Take the plug out and have a look.

Also check all the fuses you can find, make sure there not blown.

fuses are fine. i've had the carb off, cleaned it. also checked filter and cleaned that too. the old spark plug was wet when i checked it and i was told this was due to over-fuelling or the engine was flooded. so i took the plug out to let any fuel in there evaporate. fitted new spark plug and did the test, although the spark did seem rather weak to me :huh: i fitted it anyway and removed it to check if it was wet but it was dry. the only thing i can think of now is perhaps the ignition coil has gone?

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Whats in here? I havent looked but heres a manual

http://www.scribd.com/doc/43652033/Yamha-Tw-125-Manuel

Maybe it gives restistance values to check the various coils...either way it must be useful to you ?

that's the manual i've been using :D

Between ignition coil and plug cap it was 6.76ohms which is normal according to the manual. But between coil and earth it read 0.00 and supposed to be between 0.18-0.28 and it suggests to change the ignition coil if any resistance is out. My multimeter shows .1 on the screen before I carry out a test incase anyone wondered.

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measurements of the ignition coil are taken between the primary coil connection and the metal body of the coil.

And the secondary...between the end of the HT lead with cap removed and the metal body of the coil.

What page of the manual are they mentioned?

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that's the manual i've been using :D

Between ignition coil and plug cap it was 6.76ohms which is normal according to the manual. But between coil and earth it read 0.00 and supposed to be between 0.18-0.28 and it suggests to change the ignition coil if any resistance is out. My multimeter shows .1 on the screen before I carry out a test incase anyone wondered.

so the manual doesn not state the way you say you tested it...it stated the way I said it should be tested

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so the manual doesn not state the way you say you tested it...it stated the way I said it should be tested

:o oh.....well don't i feel stupid. still though, that secondary test still showed 0.00 on the multimeter and it suggests if any of them are incorrect the coil should be replaced

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:o oh.....well don't i feel stupid. still though, that secondary test still showed 0.00 on the multimeter and it suggests if any of them are incorrect the coil should be replaced

It will show 0.0 if youre still on the x1000 setting it needs to be on x1 like the book said, theres no way it will show 0.00, even your meter will have a small resistance in it's own leads

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It will show 0.0 if youre still on the x1000 setting it needs to be on x1 like the book said, theres no way it will show 0.00, even your meter will have a small resistance in it's own leads

right ok, i will check properly tomorrow then. i think because of all the frustration not knowing what was going on i've obviously made a mistake on the readings here. thanks for that though, hugely appreciated and apologies if you feel you're time has been wasted

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