hi I have rebuild my first bike an old cbr 600 over the past year. started using it a couple of months ago. i found the battery kept going flat so I investigated and found reg/rec to be at fault. I replaced it today with a second hand one. charge rate now at 13.6v. thought that was it but noticed every time I put lights on or brake light on it cuts out. but It is fine with just side lights on. any suggestions would be appreciated.
​​​​​​​thanks mike

 

It should be 14.4 or higher. you still have something bad. It could be only 2 of the 3 output circuits from the stator are working, or you could still have a toasted second hand R/R. They are known to have issues. I suggest the electrosport ones as they have a good warranty and are built better than the OEM design from 28 years ago.
https://www.electrosport.com/street-...tml?pt=stators

If you download the manual from the sticky it goes over how to test the R/R and the stator before ordering anything.

 

OK may still have issues with rec. I tested stator and with bike idling had 15.5v ac on each going up to around 50v ac at about 5000 rpm. so might have to order a new rec.

 

You should check stator coil resistance per specification in the manual. Also check stator wires to ground. Charge battery and run bike with lights off. Check voltage output at 5000 RPM. Turn bike off check voltage static. Watch the meter and see if voltage drops which could be a bad battery. Have battery load tested. You need to take all factors out of the equation. Honda rectifiers are crap...used one is suspect. Get a mosfet rectifier and be done with it.

 

Did all stator checks all are fine. battery tested and is good.
battery standing voltage 12.6v
voltage while idling 13.5v
at 5000rpm 13.7v
would a faulty rec cause it to cut out with lights on even if battery fully charged?
thanks

 

Hard to answer. They can fail in multiple ways. Something isn't right. You should see higher volts at 5000. You may have two issues. Rectifier and a short in the light circuit.

 

Going to order new rec and see what happens. will post results when it arrives.

 

New mosfet rec ordered from electrexworld.co.uk £65 +vat. should be here tomorrow. let's hope that cures it. will post update

 

Can't believe it. I thought I would strip bike ready for fitting new rec tomorrow just happened to notice ht lead didn't look right so gave a little pull and I came straight out of the coil. so pushed it firmly back in and started bike idled fine even with lights on and 14.2 volts to battery. so didn't need rec I ordered. to be fair still gonna replace just for peace of mind. But ht leads have seen better days. Anyone know where I can get a set apart from dealers as all the ones I found the plug caps don't have the disc at the top to prevent water getting in.

 

The wires with the "dust" caps are hard to find. A got a new set a while back on EBay. A couple of ideas if you want new ones would be to try looking for later model wires before they put the coils in the caps. I've also thought about trying to modify Civic car wires. The older ones have the dust caps. Not sure if the length of the boot is right but they look close.


I've seen OEM wires for the early Fireblades out there also.


NGK makes the dust caps but no kits. You could by the caps, wires and ends and make your own.


Lots of used ones on EBay also.