The voltage on my bike drops dramatically when I turn on highbeam while on tickover. It's generally around 14.6v on tickover without lights, turn them on and still OK but when I turn on highbeam and after 4 seconds it drops to 11.6v and I have to rev the bike to raise the volts. I know the lights will drop the voltage but this seems a bit much to me. The stator has been rewound and i have fitted a new battery, new genuine reg/rec, new coils and caps.. Like Zeus, my pgm's arent lasting very long and I'm wondering if this may be the reason.

Check that your charging system is actually charging. Its possible the magnets on your flywheel are just not as strong as they used to be. This will require you to measure the current out of the system.

Since we are having the same Pgm problem I’ve just been out and checked mine for comparison. I’ve got 14.5v at tickover, lights on 14.2-14.3v and highbeam on 14v. I know you said the battery is new but if you fitted it new say last year and it’s been sitting unused it could have gone down.
I’d try connecting up a battery off something else that you know is good and seeing if you still get that drop.

On batteries. What are people using, traditional or gel?
I've been using Motobat gel batteries for a while.
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Why do things simply when you can complicate them

Lithium Ion in all my bikes.

My battery is a couple of months old, gel type. I haven't left it connected to the bike and has been charged every couple of weeks. I'm hoping to have time over the weekend to have a look through the charging system. I'll see what tests I can do on the battery as well. Mot is due in few weeks so it will have been a year since I last rode it and the last time a pgm went pop.

Managed to get some checks done on the bike at the weekend.

The ac generator has been rewound but I checked anyway, 0.8 ohms on all yellow wires and around 80v at 5000rpm, don't know if the volts are OK as I couldn't find it in the manual. Only thing I noticed is when you pull the connector apart the revs rise but that might be normal I don't know.

Battery was tested on a proper load tester and is fine

The pulse generators are OK reading 214 ohms and and 219 the latter being very close to the top spec of 220 ohms. I have a new set which I tested and are 200 and 203 ohms which is right in the middle of specs so I will fit them I think. The pulse generator is mentioned in the battery undercharged part of the manual.

Managed to get some time working on the bike today. I replaced the pulse generators but they made no difference so I started looking at the headlight wiring. Disconnect right headlight and voltage still drops, plug it back in and disconnect left headlight and voltage doesn't drop. I noticed the right headlight plug and wiring has been replaced but not the left so it's probably the wiring for the left light. Both bulbs are the same 35/60's.

I have been waiting for Dmr in Japan to release their updated wiring harness which they have just done so I've ordered one of them which they have just shipped. Hoping the replacement loom will cure all the problems in one go. I'll report back when I've replaced it. If you're after a loom I went through Webike as I have used them before, they're cheaper than Dmr and Jauce and it's less confusing.

Is that a complete loom or just the headlight loom you’ve ordered? I’ll be interested to see if it cures your issues, hopefully it does.

It's a complete loom mate. If this doesn't fix it, then like yours it'll end up all alone in the naughty corner. It was around £190 delivered although there might be import taxes.

https://japan.webike.net/products/24846921.html

Looks good. I’ve ran out of ideas now (and money) so I’m hoping you come up with the fix. Did you run yours after you changed the coils for new ones and did it blow the Pgm that time or was that when it just got warm?
I’m convinced it’s the coils but I daren’t test the new ones I fitted in case I blow another Pgm.

I've only had the bike running in the shed so far. I was going to take it for mot with my spare pgm in rucksack in case, and stay local to see if it failed again but as the new loom became available before the mot I will be fitting it first. We'll have to wait and see I guess. Loom probably won't be here for 10 days, just in time for me to go away.

Hi Zeus and everyone. Had the day off today so thought I'd start removing the old loom. Had some work to do first so did that then got a call from work saying a parcel had arrived. So I shot to work and it was the new loom! I ordered it on the 30th June and it turned up at 10.38 this morning from Japan. Excellent.
I started removing the old loom and labelling everything as I went then compared it with the new one. Almost identical in length etc, couple of colours are different so I kept a note of them. Long story short, I've got it fitted with some fettling left to do and parts to put back on. Plugs spark, lights work, horn works, indicators work, oh and it Runs!!!
Should get some more work done at the weekend hopefully then mot next week maybe. The loom looks good quality and I checked there were no loose wires before fitting. I have photos if anyone is interested.

That’s good going from Japan! Hopefully it’s cured all the problems with the pgm, I think I will wait for the results of your test ride before I do anything more to mine.

Excellent news, those nips know how to run a postal service, been buying from Japan for years with no hassles at all.
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