Never been this stumped before and out of ideas now! Hoping someone's come across this and can help. Problem started about three months ago. Bike died while out practicing. walked a section, came back and it wouldn't start. Suspected the stator so fired it off to Steve Hardaker of Motoplat UK for a test and/or rewind. Got it back rewound but still no spark. Removed kill switch, checked HT coil ground, and wiring. all seemed fine so assumed the CDI was my problem and bought a new one. still nothing. bought new coil, plug cap and plugs. No difference. Started doubting the stator fix so contacted Steve again. he kindly said he would test the whole system on his test rig if I sent off the CDI and coil with the Stator. Sent it off and Steve came back saying all was good and the system was firing up a spark on his rig. Got everything back and fitted it to the bike today with no kill switch and a new earth strap bolted to the frame at the bracket for the cylinder mount. connected this earth strap to the CDI ground and the HT coil and hooked everything else up. No spark! Asked Steve whether the regulator or flywheel could be the source of the problem and he said no, the regulator wouldn't affect the ignition side, as I expected. Why would the system work on his test rig but not on my bike? 

Any part of the wiring harness not been tested ?

The whole lot went to Motoplat so all wiring and connectors seem to be okay. I've stripped the outer sleeve off the harness from the stator and found no damage or shorts. Going to have replace all connectors next. 

do you mean an earth external to the bike? I had already created a new earth to a lug on the frame which hasn't helped. Also now removed all connectors and re joined the wires without any improvement. 

Hi Hoodie2:

First check:  Is there any spark be it weak or strong ?

Take the high tension lead off the spark plug.

Remove the spark plug

Re - attach the high tension lead to the spark plug

Put on a par of heavy duty work gloves on and hold the bottom of the spark plug to the frame or the cylinder head.

Here is the important part.

Turn off the lights (test best done at night time ) and have someone kick the bike over several times in the dark.

Do you see any spark at all in the dark?

Sometimes the spark is so weak that it cant be seen in daylight.

If there is a spark as weak as it may be then we trouble shoot accordingly.

If there is absolutely no spark then we trouble shoot accordingly

Second check:  With the spark plug in the bike and the high tension wire attached.

Kick the bike over and look to see if the high tension wire from the coil is jumping the spark over to the frame as we have witnessed this before

and it was a cut in the high tension lead from the coil wire insulation allowing the spark to jump to the lowest form of resistance hence right to the frame rather than through the spark plug.

Again, do these tests in a darkened area so you can see the spark.

This will help us start to trouble shoot the bike.   

Naebotheratawe  

 

 

 

Edited August 18, 20197 yr by billyt

No spark at all Billy. Couldn't even give myself a shock if I tried. To reiterate: ht coil, lead, plug cap and plug are new.

CDI is new.

Ground as in picture made to frame and is solid.

Wiring stripped and inspected. Connectors removed and connections temporarily re made. 

Timing set at 7.5mm

Flywheel clean and magnets seem fine. 

That only leaves one thing, and I don't see how it could happen suddenly in the circumstances you describe, a demagnetised flywheel.

I was thinking that myself but the flywheel seems to be magnetised in that it will attract and hold steel tools. I cleaned it with brake/carb cleaner today and also cleaned up the coil pick ups to make sure they weren't compromised by conformal coating from the rewind. Could it be magnetic but weakened? It definitely seems like the stator works on a test rig and the resistance values are okay but when I fit it to the bike I'm not generating any current. Can anyone tell me how I'd measure output from the stator with the multimeter while kicking it over?

Timing set at 7,5mm - is that right?

As far as I know. Searched this site for timing and found a thread that showed a gap of 7.5 mm from the right edge of the stator mounting screw to the right hand end of the slot on the plate. Have tried other settings and it makes no difference.

Hoodie 

As we know the mag is creating AC.  Low voltage AC goes up to the high tension coil and is stepped up to high voltage AC to generate a spark.?

The low voltage AC from the mag is also sent up to the bridge rectifier and regulator for the DC ran electrics.

Is there any low voltage AC at the bridge rectifier/regulator input side?

 

 

 

Edited August 19, 20197 yr by billyt

Ok yellow regulator wire to multimeter + multimeter - to earth I can get 2.5 to 3 Volts AC to the regulator kicking it over. Don't know if this is useful or not but I repeated the same test with the red output from the stator through multimeter to earth and kicked it over. It would peak at 30v. I then did the same on the black trigger wire and couldn't get any reading. Any of that suggest anything?

 

Cheers.

Hoodie

 

What year and cc is the Beta so I can pull the schematics? 

2006 250cc. Its generating 30v red to ground which i'm told is indicative of a fault. 

Edited August 20, 20197 yr by hoodie2