Hello everyone! Suddenly the ammeter shows a charging current that depends on the revs. I suspect my regulator has a problem. Am I right?
Cheers, Thomas
I don't understand the regulator. I pressed the two little plates today to see if they could move freely. After that the light stopped working, but the engine started and the fuse is ok. Can anyone give me an idea of what is wrong here?
See if this helps
Thanks a lot, John! I will put it into my files although it'sd for a MCR2 (I have a MCR1). In the meantime I discovered a broken earth wire in the regulator wiring part and soldered it. The cut-off is fine. The reg seems to work again.
Cheers, Thomas
Hi all,
the MCR1 regulator still doesn't work and I am stucked. Maybe you can give me an idea. I use the Lucas manual for the MCR2 (I don't have it for the MCR1) to understand how to proceed. The attached pictures shows my situation. The earth wire of the regulator shunt coil was broken (red arrow). To solder it again to earth I unwound one coil. That seems ok for me considering the large number of windings. So, that job is clear. However, there are two wires at the field terminal. One goes to the frame and the other should go to a resistance (blue arrow). I can't find this resistance and, hence, don't know where to solder this very wire. Does anyone know where this resistance is located?
Cheers, Thomas
Quote from: Thomas on August 06, 2025, 05:13:49 PMHi all,
the MCR1 regulator still doesn't work and I am stucked. Maybe you can give me an idea. I use the Lucas manual for the MCR2 (I don't have it for the MCR1) to understand how to proceed. The attached pictures shows my situation. The earth wire of the regulator shunt coil was broken (red arrow). To solder it again to earth I unwound one coil. That seems ok for me considering the large number of windings. So, that job is clear. However, there are two wires at the field terminal. One goes to the frame and the other should go to a resistance (blue arrow). I can't find this resistance and, hence, don't know where to solder this very wire. Does anyone know where this resistance is located?
Cheers, Thomas
I'd replace the MCR1 with a modern electronic regulator. I use the DVR2 regulator (google it) on several bikes which will fit inside the MCR case so is externally invisible. The wiring is unchanged. The MCR regulators are difficult to repair and adjust so an electronic replacement is the most effective option. I also fit an on/off switch near the battery as there's a very small current drain through all the electronic regulators that I have tested. Just microamps but over weeks of inactivity it will drain the battery.
By the way, the resistor in the MCR is usually a carbon block attached to the regulator frame but as I suggested, just replace the whole lot with an electronic version.
Thanks! I am familiar with the DVR2 and use it for my second bike. As long as I have a chance to repair the MCR1 I will follow that.
Quotethe resistor in the MCR is usually a carbon block attached to the regulator frame
That's interesting! Do you have a picture?
Hullo Thomas, your request for photos made me search in one of my boxes of "bits that might be useful one day" and I found 4 old MCR regs, although I think they may be the later MCR2s. Three of them have a disc of resistive material but the fourth (which I think is an Indian replica) seems to have a sort of wire-wound resistor.
Thanks a lot, Sigarus! It seems that the reg in your fourth pic matches with my MCR2. Attached is a pic of mine plus my MCR1. I agree, the thick wire should be the resistor but that can't be found at a MCR1. I don't know the regs in the pictures 1 to 3. So, I unfortunately can't use them as a reference. I agree, regs are difficult to repair. But I want to try for the sake of originality.
Cheers, Thomas
I now bought an old working MCR1 from the workshop Ecurie35 in France and send in return my not working one so that the seller Prosper Keating can install a (cheaper) DVR2 (which I already have in my BSA). He said that MCR1 regs are like hens teeth. I opted for this track for the benefit of originality even if the reg is invisible. Mine worked well for about 10.000 miles in eight years and hope that I can report in 2033 about a still working mechanical regulator. ;D
Cheers, Thomas