Yamaha PW50 no spark, ignition ?

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ricky_191

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Hi all. I'm having trouble with my peewee again. I got a new copy carbie and then went to start it and nothing , so I pulled the plug and there is no spark. It only recently had a new coil put on and a new plug but the plug has been in there when it was running super rich.

I'm not running the stock run start switch and just a normal kill switch.

I'm a bit stuck. I pulled the cover off the magneto and the magnets have a bit of surface rust but not that bad and no dirt ect.

Any help would be greatly appreciated so that I just don't burn it. Thanks guys.
 

my67xr

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put a small screwdriver in the end of the lead instead of the spark plug
hold the metal part and kick it over, feel for a spark (should get a tickle)
ps, you wont get electrocuted


do you have some carby cleaner to wash out the spark plug ?


CDI and coil leads all still connected ?
 

my67xr

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just thinking, when you fitted the new carby, did you fit the boots over the end of the cables ?

if you still haven't had any luck, i can get the Ohms readings off the stator for you too.

the surface rust on the outside of the flywheel wont really make a difference, unless its growing over the raised pickup tab
 

ricky_191

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put a small screwdriver in the end of the lead instead of the spark plug
hold the metal part and kick it over, feel for a spark (should get a tickle)
ps, you wont get electrocuted


do you have some carby cleaner to wash out the spark plug ?


CDI and coil leads all still connected ?
Yeah it's all connected I think. I will take the carbie off and check all the wires out. I put a screw driver in the end of the plug and nothing :/ Might go through all the wiring and see if any is broken or dirty connections.
 

ricky_191

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Hi all, It's still not working :( I cleaned all the connectors out and I think they are in the right order because the wiring colours match up. I put a screw driver in the end and got nothing.

The tabs in the magneto are a bit rusty where that little bit rubs on them. Is there a way to get that off and get all the rust off and maybe adjust it ?

I don't think it would be the coil because it's only new but would one off a pit bike fit and work just to test it ?

Also might go get a new plug. You can't get them single any more because they come in a pack for out boards. I think it was just the number that was on mine though.

I don't really know what else to try :/ Any help would be appreciated.

Thanks
 

my67xr

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my67xr

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the spare pitbike coil you have should work too, make sure it has a good clean terminal and a good earth.

do you have a multimeter, you can test your current/new coil ?
 

ricky_191

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I got the pit bike coil off and found my frame has bent -_- so over motorbikes.

I put the coil on and only got a few small sparks and not every kick :/ Does any one know what's wrong ?
 

my67xr

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test the Ohms on the new coil to check it's ok still, then refit it.
see if it works when it's back on.

it could possibly be the stator or the cdi

the frames will bend with adults riding them they aren't that strong.
 

ricky_191

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How do I test it ? just set the multi meter on ohms and test at the coil or the spark plug lead ?

And it's my pit bike that's bent , the engine brackets are bent to one side :/ And it's been strengthend with more steel ect and I don't ride it that hard. might get some more steel welded in and make the two mounts joined so they are one unit.

Over this peewee though. They are tricky to work on.. Thanks mate
 

my67xr

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to test the Primary Side coil reading,

set the multimeter to 200 Ohms
put one lead to earth, the other to the power in terminal on the coil
it should read about .6=.7 0hms
if it reads 1 Ohms constantly ( like when the leads are not touching anything) the connections are bad/dirty where the leads are touching the terminal
or the coil is no good.


to test the Secondary Side of the coil,
first unscrew your spark plug cap/boot from the end of the lead.
the set your meter to 20,000 Ohms
put one lead to the power in terminal on the coil, the other lead needs to touch the wire in the end of the coil lead the end (where the spark plug cap screws in)
you should get a reading around 3 Ohms to 5 Ohms


test it and post the results

cheers, craig
 

ricky_191

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Hi guys. Sorry I haven't been on here for a while. After having my pit bike smashed to bits and the peewee not working, I haven't really wanted to play with motorbikes for a bit.

So I went and got a new multi meter today and did the test above. I did the first test I put it on the coil in lead and the ground and got 1.6 ohms :/

Then on the coil lead I got 4.20 ohms which from above is in the right limits.

So what could be the problem ? This coil isn't that old but it is a china copy I think. And then I have a copy carbie as well that's new and a new plug. So I think it's a problem with the coil. Any ideas ? Could the contacts just be dirty ?

Thanks guys.
 

ricky_191

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I cleaned the contacts because they were pretty dirty and I put a bit of bulb grease on them. I tested it again and got 1.6 ohms again.

So could the coil be broken then ?
 

my67xr

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does the coil have 2 wires going to it ?
a power lead from the cdi, and an earth lead ?

or is it just 1 power lead, and earth through the coil mounting point/s ?
 

my67xr

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where the coil mounts touch the frame, is it clean bare metal ?

i will get the readings for the stator tomorrow, off Cjs' bike and post them up for you too
 

ricky_191

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Yeah I pulled the coil off again and one was pretty dirty and the other had over spray on it. So I got some 80 grit sand paper and cleaned them up. They are both shinny and clean. I also put some bulb grease on the contacts because it's meant to stop water and help the connection.
 

my67xr

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yeah, that's it, the contact points will be good for years to come

i'll post up the stator readings sometime before lunch today
 

ricky_191

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I forget what brand this coil is. I got it off ebay and it seemed to work fine. I had that problem with the bike cutting out when it was hot and I think the coil was getting hot and just making the bike stop. So the new coil has stoped that problem but then the carbie was dirty and I pulled that off to clean it and busted the needle -_- and then I got the copy carbie..

After all that now it won't work.. Such a pain when these things stop working.
 

my67xr

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your coil might still be ok with that slightly higher reading off the primary circuit

but we need to check the condition of you stator windings, set your multimeter to 2000 Ohms,

pull the seat off, and find the connections from the stator wiring, to where they join into the wiring loom.

unplug the black w/red strip wire from your stator.
put the red lead from your meter, to the black w/red stripe wire from the Stator.
and the black lead from the meter, to the frame earth.
our PW reads 300 Ohms
now plug the black w/red stripe wire back in

now unplug the white with red stripe wire from the stator,
put the red lead from your meter to the terminal on the end of the white w/red stripe wire from the stator
and the black lead from the meter to the frame earth
ours reads .3 Ohms
plug the white w/red stripe wire back in

let me know what readings you get
 

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