MZ/MuZ Riders

Hi everyone, this is my 1st post having found this site in desperation whilst looking for guidance online

My sons SM125 has been running well since he got it a year ago, he has just passed his A1 and the L plates have come off! Just got him a Mastiff for when he is 19 (about 18mths from now) given the problems I'm having with his SM125 it will probably be then next time he rides a bike! If there is anyone out there who can help reduce this then please help!

About 2 weeks ago his sm125 just stopped on him and wouldn't start again.

Ive done lots of things since to try and fix this but nothing is working....

The problem as it stands is I can only get the odd occasional spark when earthing a plug in the suppressor cap.

What I have checked / done

1 Cam/Crank timing good
2 flywheel timing is good (as in the woodruff key hasn't sheared)
3 All connections good and clean
4 Tried a new spare CDI
5 Fitted new coil and lead
6 Compression 155psi
7 Diode 31 replaced (BY253 S3)
8 Relay 19 replaced (Even tried it shorted across pin 3 and 5)
9 Side stand switch works (tried it shorted out)
10 Set gap on flywheel pickup to 0.5mm bang on
11 In desperation tried new reg rec
12 Earthed Neutral switch to ensure it thinks its in neutral
13 checked wiring loom for damage
14 And..... Taken most of the skin off my knuckles.....

Can anyone out there think of anything else? (PLEASE)

Thanks all!

Update

Don't know where it came from, but, I had an idea......

I disconnected the neutral switch

I put it in a high gear and pulled the clutch in

And voila! A spark on every stroke!

Tried the same thing with the plug in and away she fired

Won't work in neutral so it must be bloody diode 31

The new diode I fitted was an equivalent, after some research it's rated at 200 v the original is rated at 600 v

I cannot find a diode in the UK but have found and ordered 10 from a German electronics site exactly the same as the original ( less than a pound for the 10 ) although 10 Euro postage.

So...... Next weekend may bring success.....Hopefully....

Unless anyone has any other suggestions????? Gratefully received if you have.

Still, I'm taking this as progress after the last two weeks.

95% of the problems i have had with my rt125 have been traced back to some thing electrical...

and any thing you do to make it go faster makes it go slower and it uses more gas
so do not waste money on mods

dave

Thanks Dave, the bikes totally standard, other than all the plastics have been blue carbon fiber wrapped, hopefully this isn't contributing to the problem

Anyone ever had the same problem?