Charging problem?

[Brian.Challinor]

Hello, The problem I have is on start up the dynamo (c35sd) on my 51 sq4 doesn't seem do do anything until after about a minute of running it comes to life, I have to rev the engine and sometimes switch the lights on and off to get a + reading on the ammeter. I overhauled the dynamo during the rebuild. I have a new battery fitted and use a DVR2 regulator. After the dynamo kicks in it charges ok, but I have to go through the same sequence on initial start up. I'm thinking the field coils are weak.

[JohnnyBeckett]

hi have you made sure the dynamo has got a good earth and all the earths on the bike and the regulator can some times be a bit lazy to start up

[Brian.Challinor]

Thanks for reply, I will check earths but I think they are good.

[JohnnyBeckett]

hi Brian have you check the volts at the battery with the engine running, my 6v is showing 7.2 volts with the engine running but no Amps till i rev it or ride it then it shows it charging i put it down to the new type of regulators

[Brian.Challinor]

Will check tomorrow, the bike runs a bit rough until it starts charging, then its fine.

[admin]

My magdyno dynamos do this.
The electronic regulators, fitted inside the original reg boxes, seem to want a bit of current (generated by revving ) to wake up.

[Brian.Challinor]

The reason I posted was because I don't like revving the engine from cold. Its made feel a bit better knowing that its a ''problem'' with the regulator and not the dynamo probably.

[chris.shearwood]

You can run a wire from the Dynamo wire to the Field wire with a momentary switch in the circuit. Touching the switch should be enough to wake up the regulator. A bit of a bodge but what the H***

[will_curry]

The problem is a function of the internal resistance of the electronic
regulator. Chris's fix works by by-passing the regulator momentarily.

[Brian.Challinor]

Heres what the makers hd to say