Jaws Motorcycles
Tel: 01842 754415

Reg/Rec Guide (by JAWS)

Charging problems.

 So your Bird is not charging.

You have trolled the forums and most are saying it is the reg rec, but you do not want to spend your hard earned on something that is not needed.


Follow this simple guide and you can work out what is needed.


1)  Remove the seat cowl

2)  Unplug the reg/rec ( See note *i )

3)  Set your multi-meter to 200v AC range ( that is the one with the wavy line not the one with a straight line and or dotted line )

4)  You are going to check the generator output voltage so you need to start the bike

5)  Looking at the reg/rec plug(s) you will see three yellow wires. It matters not what order, but for simplicity sake I will call them wires one two and three.

6)  Start the bike and get someone to hold the revs to ‘about’ 2000 rpm.  Now use the meter to check the voltage across wire one to two, then two to three, and finally wire one to three.  All three voltages should be quite close and all around the 26v AC mark.  The exact voltage is not critical, this is a ‘ball park’ figure. What is critical is that all three voltages are within 1 or 2 volts max.

7)  If one of the voltages is significantly different, or indeed you are not getting anywhere near the correct voltages on any of the tests, then the generator coils have gone a.w.o.l.

8)  If the voltages are all ok, then the reg/rec is the problem.


If the generator coils have gone phut there is every chance that is all that is wrong.  However !

It has been found that the original problem has been the reg/rec, which in turn cooked the gen coils.

If you find the gen coils are faulty then the first step must always be to replace them.

After you have fitted them set up the multi-meter on 20v DC and get someone to hold the probes on the battery terminals for you.

Start the bike and make sure the indicated voltage starts to go up immediately.

If it does not move, or indeed drops, turn the bike off immediately as it would mean the reg/rec has indeed gone duff.

Providing you do this quite quickly ( say, within about 45 seconds which is actually quite a long time ) no harm will come to the gen coils.. Of course the down side is that you will have to replace the reg/rec as well

We always keep the coils, the various reg/recs and the gen cover gasket in stock.

I am usually available from 9 am until 10 pm daily on 01842 754415 or 0781 8822887 should you need any further help or clarification on any of the above points 

As an aside, the tests suggested in certain manuals are pretty useless unless you have access to a VERY expensive meter, or a stabilised power supply and a scope, as a ‘normal’ multi-meter is no where near accurate enough to make the very fine measurements required to establish if a gen coil has a partial short ! ( But of course, they do not actually mention that little fact !! ) 

Note *i ….

On the carb bikes there is one single plug but on all EFI models there are two. It is the one with the three yellow wires you need to unplug.