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TW125 doesn't start


e30lou
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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

ok we'll try again tomorrow, my time hasnt been wasted...after all you condemned your coil and as far as we know to date...it might not be faulty.

Test the plug cap disconnected 10k ohms and the two tests of the coil windings with the cap not insitu...just follow the manual and report back...to be continued

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I listened to the vid again and although i'm no good at the electrical stuff,,,,,,,,,,,,,,,,,,,,,,,,,,, it sounds like there's no fuel getting through for the bike to start.

Engine is spinning but nothing there to catch,,,,,,,,,,, this can be no fuel or no spark.

As the fuel issue is the easiest to sort out, thats where id start to look at first.

Nite nite now,,,,,,sleep well

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ok so i followed the manual to the letter to do the resistance tests. did continuity tests on the switches too. these are my results:

1. Spark plug cap, it wasn't completely clear where I should be putting the -ve probe so I went to ground on the ignition coil and got 7.83, should be 10k but may have tested this incorrectly :icon_confused:

2. Ignition coil primary resistance 0.06, should be 0.18-0.28 :thumbdown:

Ignition coil secondary resistance 7.83 :thumb:

3. Pickup coil 775, should be between 656-984 :thumb:

4. Source coil 778, should be between 624-936 :thumb:

5. Diode continuity, there was continuity both ways :thumbdown:

6. Main, engine stop, start, sidestand and neutral switches all have continuity :thumb:

So, looking at this I would assume I need to replace the ignition coil and perhaps the spark plug cap(depending on whether the test was correct?)

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I listened to the vid again and although i'm no good at the electrical stuff,,,,,,,,,,,,,,,,,,,,,,,,,,, it sounds like there's no fuel getting through for the bike to start.

Engine is spinning but nothing there to catch,,,,,,,,,,, this can be no fuel or no spark.

As the fuel issue is the easiest to sort out, thats where id start to look at first.

Nite nite now,,,,,,sleep well

had a look into this too, checked the spark plug after cranking it a few times and it was completely dry so i guess you were right, no fuel. So, stuck a clear tube on the overflow pipe and did the float check....it was far too low! so took carb off and cleaned it up(again) paying particular attention to the pilot jet and adjusted the float. fitted carb back and cranked it again, spark plug still dry. so i tried putting a little fuel into the plug hole but that did nothing :angry:

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ok so i followed the manual to the letter to do the resistance tests. did continuity tests on the switches too. these are my results:

1. Spark plug cap, it wasn't completely clear where I should be putting the -ve probe so I went to ground on the ignition coil and got 7.83, should be 10k but may have tested this incorrectly :icon_confused:

2. Ignition coil primary resistance 0.06, should be 0.18-0.28 :thumbdown:

Ignition coil secondary resistance 7.83 :thumb:

3. Pickup coil 775, should be between 656-984 :thumb:

4. Source coil 778, should be between 624-936 :thumb:

5. Diode continuity, there was continuity both ways :thumbdown:

6. Main, engine stop, start, sidestand and neutral switches all have continuity :thumb:

So, looking at this I would assume I need to replace the ignition coil and perhaps the spark plug cap(depending on whether the test was correct?)

test the cap with it disconnected from the HT lead, just shove a probe into each end, doesnt matter which way..meter to x1000 some caps have no resistance at all and from your readings yours may well be one of them so if so get a new cap with your coil.

Looks like you do need a coil then...is it listed on wemoto site?

whats this diode?

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test the cap with it disconnected from the HT lead, just shove a probe into each end, doesnt matter which way..meter to x1000 some caps have no resistance at all and from your readings yours may well be one of them so if so get a new cap with your coil.

Looks like you do need a coil then...is it listed on wemoto site?

whats this diode?

not too sure on the diode but it was in the manual to test it but to be honest, I don't think that makes too much of a difference.

i've just taken the spark plug cap off, measured the resistance and comes out at 4.90....upon looking closely at the plu it says its only a 5k resistor cap and it should be a 10k so i'll definitely be ordering a new one along with the ignition coil. i wonder why a 5k was on there in the first place :blink:

coil is on wemoto but struggling to find the cap anywhere at the moment....

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not too sure on the diode but it was in the manual to test it but to be honest, I don't think that makes too much of a difference.

i've just taken the spark plug cap off, measured the resistance and comes out at 4.90....upon looking closely at the plu it says its only a 5k resistor cap and it should be a 10k so i'll definitely be ordering a new one along with the ignition coil. i wonder why a 5k was on there in the first place :blink:

coil is on wemoto but struggling to find the cap anywhere at the moment....

Most are 5k in fact, it's unusual to find a 10k specified.

While youre ordering stuff check the correct plug is fitted too, I assume a non resistor type plug should be fitted...check the manual, FYI resistor type plugs have an 'R' in the code

here's a 10k cap

http://cgi.ebay.co.uk/NGK-Spark-Plug-Caps-LB10EHF-Red-5mm-HT-Cable-/220810886862?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33695abece

so do i assume the coil secondary measures what you said minus this 4900 ohms? or did you measure it correct with the cap off?

Now you have found a difference between your bike and the manual can you be sure the manual is the correct one for your year/model bike?

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Most are 5k in fact, it's unusual to find a 10k specified.

While youre ordering stuff check the correct plug is fitted too, I assume a non resistor type plug should be fitted...check the manual, FYI resistor type plugs have an 'R' in the code

here's a 10k cap

http://cgi.ebay.co.uk/NGK-Spark-Plug-Caps-LB10EHF-Red-5mm-HT-Cable-/220810886862?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33695abece

so do i assume the coil secondary measures what you said minus this 4900 ohms? or did you measure it correct with the cap off?

Now you have found a difference between your bike and the manual can you be sure the manual is the correct one for your year/model bike?

I've got the correct plug, double checked from that manual and it is the right year for my bike. i measured the secondary with the cap off

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here's another video for everyone, it shows what happens when i try to bump start my bike....you can hear that "clicking" and it does sound very much like it's coming from around the engine area. it may just be i wasn't going fast enough. see what everyone thinks

My link

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I assume the noise was when you let out the clutch. Just sounded like engine noise to me but with some induction nose as if you had the throttle open...or there was no spark plug in :lol:

yes was when i let out the clutch. i didn't open the throttle and the spark plug was in ;)

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Yip " dosn"t sound good, have you a compression tester ?

yeah I said ages ago it seemed to spinning a bit too freely on the starter.

so then take the plug out is it possible to get a seal with your thumb over the hole, operate the kickstart (key off) and the compression should blow past your attempt to seal it.

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Not got a compression tester but heard of that thumb over the plug hole test. There's no kickstart so I'd have to use the electric start assuming that's safe enough? I've had a look through that manual, checking the valves and adjusting them seems fairly easy so will give that a go tomorrow. Wish I had a garage I'd be on it now and all night :)

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Not got a compression tester but heard of that thumb over the plug hole test. There's no kickstart so I'd have to use the electric start assuming that's safe enough? I've had a look through that manual, checking the valves and adjusting them seems fairly easy so will give that a go tomorrow. Wish I had a garage I'd be on it now and all night :)

If you do it by the elec start but your plug in the cap and make sure it is well earthed and out of the way of your hand. Its no fun getting a belt from 1000's of volts ;)

at the back of my mind is the possibility your cam chain has jumped the teeth on the cogs so you lost compression perhaps...just a thought!

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Right ok, will have a looksee tomorrow as I'm checking the valves. Will do the compression test beforehand though. Hoping to get the bike back running by Friday as it's back to work then

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hey everyone. took the valve covers off and camshaft cover off this morning and this is what i found:

1. took the camshaft cover off and it looks as if the timing chain had been rubbing on the inside somehow

SANY0225.jpg

2. looking at the exhaust valve, the screw was damaged/cracked. it was sat very tightly against the valve tip so i tried adjusting it but the valve kept moving up with the screw and there was never any clearance :blink:

SANY0220-1.jpg

i also noticed the top of the exhaust valve cover had a little indent inside it which is where i think the top of the screw had been hitting it

i made sure the piston was at TDC before i touched the valves. i could also see both valves move down and up so there's no issue there.

apologies on the size of pics

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But the valve will be open at TDC on the exhaust stroke, turn the engine to the next TDC. The valves are only both closed every other TDC (I think)

Also it looks like the timing chain is slack...maybe it has jumped and the timing is out now well have to see.

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But the valve will be open at TDC on the exhaust stroke, turn the engine to the next TDC. The valves are only both closed every other TDC (I think)

Also it looks like the timing chain is slack...maybe it has jumped and the timing is out now well have to see.

i thought the same and turned it to next TDC but no difference. infact i checked the clearance at several stages of the valve stroke but it stayed the same. the intake valve was a doddle to adjust and when i loosened the 10mm bolt i could turn the adjustment screw easily with my fingers. this wasn't the same for the exhaust valve, i had to turn it with pliers but every time i did the valve followed the screw up if that makes sense

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