CMES Regulator - dead or alive?

[nigeldtr]

I have an M21 which I bought a while ago, just blown the dust of, runs fine but no charge. Dynamo seems to be extremely healthy but nothing happens when reg is connect. There was a blown 20 A fuse so I suspect its been cremated! Its CMES Bristol job, can't seem to get them on the phone - anyone any experience or know how to test it before I buy a new DVR2.

Thanks

Nigel

[Richard]

I do not know much about them but if you have checked your dynamo is ok then you could check your wiring from dynamo to reg is ok by joining F and D at the regulator end( disconnected from reg.)and checking the output between F & D and earth at a fast tickover if this is ok and you have no output to the ammeter when reconnected and engine running than i suspect the regulator is the problem.
I hope others will agree with this as I am not an expert but hopefully manormike will be lurking if not at the international and can confirm
Richard

[nigeldtr]

Hi Richard,

Thanks for the reply. With the reglator leads joined and with a few revs, the voltage shoots up - I tend suspect the regulstor is dead!

Nigel

[Richard]

Nigel with all the leads connected to the regulator you should be able to put your meter set to DC volts across the lead that goes to the ammeter from the regulator and chassis and you should have 12volts when you start the engine on revs you would exoect that to go up to about 13.2volts.
If you have a 6volt system read that as 6volts going up to 7 volts
If it stays at the lower voltage then I think you can say it is the regulator
Richard

[nigeldtr]

Hi Richard,

Thanks for the reply. It is running 6v but the actual bike wiring is for -ve earth and the regulator for +ve ???? On checking the dynamo this is also pushing out +ve V when the leads are connected together. The joke is the ammeter connections are also for +ve earth. I suspect that the battery has been fitted the right way for the colours (red +, blk -) but wrong way for the earth and regulator. This in turn has shot the regulator which has in turn re-polorised the dynamo to -ve earth (just guess work). All a bit wird and wonderful  .

Time to buy a new regulator and do the job properly.

Nigel

[Richard]

At least you may have found the reason why the reg. failed  and can correct the situation before fitting a new one.
Hope all goes ok
Richard

[a10 gf]

A couple of fuses here and there can do miracles.

[nigeldtr]

Fuses and DVR2 fitted - works great. Shame my GF dynamo can't match the M21 dynamo performance

Nigel