Moto Guzzi Le Mans Mk 1 1978 850cc

[NeilD]

Newtronics site says the charge light do oesnt work with their reg rec so assume the rotor is 'excited' ooo err  by another means ?   

[Bixxer Bob]

God knows.....

I can rig 12v to the rotor, but the output will be on max all the time.  I have a circuit diagram for the motronics but haven't had time to study it yet.  More reading to do....

[metalguru]

God knows.....

I can rig 12v to the rotor, but the output will be on max all the time.  I have a circuit diagram for the motronics but haven't had time to study it yet.  More reading to do....

Just wondering here, as I remember on the old Lucas ACR alternators the warning lamp was 2.2w.
If Newtronics say thier reg/rec doesn't require the warning lamp, the theory could be the warning lamp is bridged so a 12v switched supply is sent to excite the field, thus causeing full output from the generator regulated by the reg/rec. It doesn't sound like a foolproof mod as the field is getting full amperage and may end up as an efficient heater, whereas with a lamp or resister in line it will only allow limited amps to the field, or am I rambling on a tangent!

[Sin_Tiger]

Surely if there is amperage going through the lamp it will illuminate all be it dimly, maybe that's considered normal on Italian electrics.

[Bixxer Bob]

Newtronics does away with lamp. Has 3 ac wires, yellow, red charging wire, brown sensing wire and white wire which feeds rotor coils.  It must vary output on white to match need sensed on brown.

Only thing to do now is check all connections (which means pulling half the bike apart to get to them) then run bike with it all assembled and check output on white. If nothing, guess is reg rec is fubar'd

[metalguru]

Would you believe Honda had this system when the 650 fours came along. They caused much headscratching too.
Many of the charging faults were physical, even though it looked ok, it wasn't. One of the most popular was the brush set which looked ok as quite a bit of meat left on them but it wasn't quite enough to make contact with the comm. Another novel solution to a non existant problem. This system was sans lamp too.

[Bixxer Bob]

Iv'e read about the brush issue already so one of the first thing to check.  Enough studying, time to get dirty....

[Bixxer Bob]

We have volts!!! 

14.7 of the little bar stewards to be exact!

Simple fix once I found it, dodgy connection on the reg/rec power supply.  Once fixed I immediately had 11.8 volts on the white (exciter) lead going to the rotor windings.  Re'assembled the alternator, put the tank back on, fired her up and voila!!!

Somehow, the charging light works as well, butonly goes out when output reaches 14v so is on lit on tickover and at low revs.  Then it stopped working so I have that to look at next week.

Now she needs a good clean, the cowl and screen putting back on and the brakes and clutch going over.  Then she'll be ready for an MOT.

Thanks everyone for their input,  no doubt we'll be at it again when I start on the Laverda.

[cosmo]

... when I start on the Laverda.

"Italian manufacturer of high performance motorcycles"

Have we not learned?!?!?  :)

Cosmo

[Bixxer Bob]

There are11 in the collection, all Italian; Morini, Ducati, Laverda and Gilera.  Oh, and a GasGas.

[metalguru]

So by the end of this you will have found all those little Italian intricate gremlins designed in at manufacture and you will have pulled every single hair from your head painfully one-by-one.

GOOD LUCK.

[NeilD]

well with those 'Zane' Laverdas, the engine was more likely to have exploded before the electrics had chance to give up the ghost! 

[Bixxer Bob]

Cheers Neil!! 

This is the baby...

[John Stenhouse]

My good friend Marcus had one of those......he loved it!