MZ/MuZ Riders

Hi all ,
Problem with the TS 125 again.
When I put the main lights on the engine cuts out.
I have had a look around the posts at similar problems but apart from putting in a new battery other peoples solutions are hard to find.
Anyway here's what I have done and found , replaced points and condenser , replaced battery with 6v 14Ah SLA , replaced reg with solid state one , replaced fuse box with 2x in line fuses , repolarized the dynamo.
Unfortunately when the bike ticks over and I switch on the headlight the battery voltage falls away from 6v to about 5v and the engine misses and cuts out , what I have noticed is that the battery is not charging at tickover ( amp meter inline ) but the charge light is off ??? . When I rev the bike it charges at +6 amps @ 7.5v .
The wiring all seems ok and I have checked the connections for the charging / ignition , I'm thinking now that maybe the brushes are at fault , has anyone else had a similar experience ?
Thanks in advance.
Rich
Devon
1986 TS125 Alpine

take the lamps out and try the test again ,(ie , whilst engine running try the light switch again ) if it still fails then its a current drain somewhere in the wiring , if it does not then the load must be taking all the lions share of power and reducing power to the coil.in essence , dynamo old and frail,lol. wouldnt expect the charge circuit to work on idle anyway,

old and frail springs on the dynamo brushes and clean the commutator
that's the copper place where the brushes run
more spring pressure should = more voltage and current flow
these things do not put out very much power any way
think about a led replacement for tail lamp to save on drain
dave

Hi every one .
I have found the problem and hope that explaining it here may help someone else also.

The symptoms I had where that the engine would miss and cut out with the headlight on , this also happen occasionally with the indicators as well .

I changed the battery , reg , points condenser and the brushes all to no avail, so what I decided to do was work my way through the connections .
As the connectors are crimped I soldered these and cut off and replaced the grubby ones soldering these as well.When I say soldered I mean I soldered the connector to the cable not soldering the connector to the thing its plugged into.
Anyway the problem was within the headlight , there is a thickish red cable , this is from the battery . There are many black cables , these feed the 6v (after the switch) to the coil , horn and brake light as well as the indicators . Some of these black cables are bunched into one connector , after replacing the connector on these thing improved straight away .
Everything works now . The headlight is bright and you can use the indicators with the headlight on , and of course the engine does not cut out. Hope this helps

i have been a fan of soldering the crimp connectors on for years and not crimping them in place...
if you have a wire problem the wire can be replaced
i carry a gas fueled soldering iron on trips so i can salvage the connectors and make field repairs
nothing like running out of spade lugs in the middle of no where

up the end of the handle bar in a plastic bag with a string and a cork
great place for solder spade lugs and even a 3 foot piece or two of number 12 wire
fixed so you can fish it out of course
dave