Cbf1000 wouldn't start today

[fastbob]

This is a bit mad ! Rectifiers to suit all pockets . Interestingly the most expensive one is not by Honda . I've got a £13.99 one on my ER5 and it's worked for two years so far .

[Beans]

So, here's a video of the multimeter when I run the bike at 5000rpm

https://youtu.be/zO7tjuMLuH0

It reaches 12.47 /12.48v.

Do I need to do the test with the headlight on full beam and the brake light on?

[Stu]

So, here's a video of the multimeter when I run the bike at 5000rpm https://youtu.be/zO7tjuMLuH0

It reaches 12.47 /12.48v.

Do I need to do the test with the headlight on full beam and the brake light on?

 

Check all connectors from the reg/rec it could just be corrosion!

Try testing at the connectors too and see if the readings are different

You need higher than that

[JRH]

Charging circuit fir the GSF1250 has is 14.0 - 15.5 volts at 5000 rpm.

Edited April 9, 2019 by JRH

[Mississippi Bullfrog]

At rest you're usually looking for around 12.5 and above - at 5000 rpm (as others have said) you want to be seeing 14+v. Anything less and nothing is being put into the battery.

Edited April 9, 2019 by Mississippi Bullfrog

[Beans]

... it could just be corrosion!

Someone's trying to keep my spirits up

[billy sugger]

running the test with headlight and brake light on just means you are putting the system under full load to see whether the output from the alternator changes by much, but with just under 12.5 volts at 5000rpm means it is not putting out enough to keep the battery charged up.

You could try checking the output of the alternator at the connector where it joins the reg/rec. this is usually a three pin connector with all yellow wires in and out, and a separate connector with two wires probably one green and one red, that go to the battery.

measure the resistance between each of the three yellow wires at the alternator end and all 3 readings should be the same if that is ok do a continuity test between each yellow wire and a suitable earth---there should be none.

[Stu]

... it could just be corrosion!

Someone's trying to keep my spirits up

 

OK to put a dampener on it this is the first thing that should have been checked before spending money

If your not sure how to check the reg/rec at the terminals then don't worry it's normally very easy

You usually have two plugs one with 3 yellow wires and another with any number of black and red wires! Sometimes one of each sometimes 2 of each!

Stick the probe between the black and read and take the readings from there also pull apart the plugs and check for corrosion

If still the same replace reg/rec as its a Honda

[Beans]

OK to put a dampener on it this is the first thing that should have been checked before spending money

I know, I'm kicking myself, I can get a stator for about the price I paid for the battery. It seems from today's research that Stator is statistically likely to be at fault on the mk1 cbf, not the reg/rec. Anyway I am taking it to my trusty mechanics tomorrow night for his analysis and I will update this thread.