Testing a stator?

[choppedxs]

Ok so I have a WR250f and I lent it out and of course when it came back it didn't go (I know).
It won't start with cranking or kicking but will start with push start. Replaced sparkplug and tried to get a spark against the engine but nothing with cranking or kicking. So I did all the tests in the manual - main switch, neutral switch, ac magneto (pickup), coil, checked for shorts and nothing. I even checked valve clearance as Yamaha dealer thought it was that but gaps are all in spec.
I am starting to suspect the stator but have no idea how to test it. There are 4 wires coming out of it - 2 from pickup and 2 from stator. There is no test listed for the two coming from the stator but there must be some sort of test I can do on it. Any one out there know?
Any other ideas out there for what is causing this lack of spark would be appreciated.

[NinjaNanna]

The question is what is the difference between roll starting and kick start/starter motor?

Does the bike have a de-compression circuit that would be in use during kick/starter that isn't in play during roll starts.

Does the bike have side stand, neutral, clutch cutouts that would be in play during kick/starter that isn't in play during roll starts.

What else is different during the 3 scenerios?

[oneofsix]

The question is what is the difference between roll starting and kick start/starter motor?

Does the bike have a de-compression circuit that would be in use during kick/starter that isn't in play during roll starts.

Does the bike have side stand, neutral, clutch cutouts that would be in play during kick/starter that isn't in play during roll starts.

What else is different during the 3 scenerios?

agreed, not that I know shit but I have ridden a FXR with a fucked stator and it could be either kick or roll started. Basically the difference between roll and kick starting is what is turning the engine over, the back wheel or the kicker. Therefore if it one way but not the other then it must be one of the frilly bits (cut out switches etc) interfering, wont be the stator or the other basic engine mechanics.

[NinjaNanna]

One other thought, how's the battery? When cranking does it do so with its usual gusto? If its low then conceivably the voltage is too low to get a decent spark while cranking and using the kick start.

Conversely when roll starting you have continual output from the charging system to supply the neccesary voltages for the ignition.


Just a thought, could be way off, but easy to confirm with a set of jumper leads to another vehicle with known good battery.

[Jinxycat]

really the only thing that is different would be the speed of engine turn over, i guess if the stator is weak the faster spinning motor could give a bit more voltage?

what do you lot think?

[noobi]

http://www.youtube.com/watch?v=wbHSfHjMp28

[choppedxs]

Thanks for all the replies.
as far as kill switch, clutch switch, neutral switch they all tested fine and the motor cranks over fine (which it doesn't when the neutral and clutch switch are shorted). The kill switch can't be the problem as it runs fine once going. It all seems to point to not enough voltage under cranking and kicking but the high speed of tow start seems to produce enough.
There is an auto decompression, not sure how that would play into it - maybe as it is easier when cranking less voltage is produced then when towing. I also tried hooking it up to my car battery with jumper leads and cranking it but no luck.

I took a look at the video which is good but had a little trouble trying to figure out which wires I need. I have 4 wires - a red and a white wire that come from the pickup (which test fine) and a yellow and a white (from the stator - the yellow goes to battery and lights and the white to the CDI) which there is no test for in the manual. I am assuming that the wires the guy in the video is talking about would be the red and white ones. Maybe there is nothing to do with the other two. So I put my volt meter on the pickup wires and cranked it - nothing but I have a feeling my volt meter does not handle AC Volts (is a cheapy) so this may not mean anything. I will get a better meter from work tomorrow and try again.

If you watch the video let me know if you think I am testing the right wires.

Oh and I talked to Yamaha and they reckoned it may be the valve clearance making it hard to start and that I wouldn't be able to see the spark. I have seen it spark once or twice so am pretty sure that I can see the spark if it happens (it was pretty obvious when it sparked). but I checked the clearances and they were fine so another thing eliminated.
all ideas welcomed

[Rupe]

how easy does it push/crash start?

What were you intake valve clearances?

[barty5]

compression check it lower compression when kicking and starter with decomp being used hence when roll started engine turns over quicker and makes up for it. is a bit like having bad valve clearances.

[choppedxs]

The valve clearances were all in the middle of the manual ranges so no dramas there. Don't have a compression tester but the piston is only 20 hours old (is not a race bike) so would not be impressed if compression was down enough to stop starting and besides I should still see a spark no matter what the compression is or is there something tricky about modern bikes that means they don't spark if they are touched against the motor? Anyway I have an AC Volt meter now so will be able to test it soon for volts coming out based on the video posted earlier.

[choppedxs]

So after trying to get readings from all the stator wires and getting nothing I took the engine cover off to see what was going on. What greets me under the engine cover but two little bolts from the flywheel sitting all on their lonesome. And every time I was cranking the engine over doing my tests the bolts were slowly mincing my stator - nice. So new stator hopefully will sort the issue. hopefully has not caused any other damage but willl be taking all the others out to add copious amounts of locktite!
Thanks for all the help.