Any Bike electrics gurus out there who can help please ?

[Berniebloke]

Hi folks. I have got a charging problem with my VFR. I think I have got to the bottom of it but am a bit of a novice with electrics so if possible would like to discuss with someone who knows a bit about bike electrics so that I can run by them what I have done and my conclusion (nothing binding of course).

My problem is that my bike isn't charging the battery. I have carried out various checks as per the Haynes manual and now believe that my alternator is kaput and possibly also my rectifier.

Would be good if I could possibly have a chat with someone who knows about such things and I would fully explain from there.

Any help would be greatly appreciated before I embark on buying new parts

Cheers
Bernie

[WR6133]

Do you have a multimeter? If so check the wires that enter the rectifier (this is the pickup from the alt), if they are in spec then go on to check the output from the rectifier to the bike. If the problem seems to be the alt check its not the pickup itself is damaged (physically check and check the resistance).

Do these with the engine running and the battery disconnected (take out the fuse). You may notice the voltage under expected at idle and slightly over if you give some revs that's not a huge concern unless it's massively out of spec.

[WR6133]

Forgot to add you want around 12-15V AC coming from alt and around 15V DC coming out of rect (a bit either side is ok but it it's way off things are knackered). I don't know what the resistance on the wires should be with your bike that should be in the workshop manual.

I'm no guru on this just had a similar issue recently that turned out my pickup was knackered (really dodgy Chinese wires). You may want to double check my figures with your guide or an owners club etc.

[Berniebloke]

Thanks for the tips

I have ran all tests with aMulti meter as per the Haynes manual for the alternator and all in spec (resistance and continuity). Checked RR as per manual and voltage output from RR with just the ignition on is less than at the battery (Haynes says they should be both exactly the same with just the ignition on)

I then further tested continuity for all the wires and connections - all OK

I then unplugged the connection from the alternator to the RR, set my multi meter to AC and measured the output direct from the alternator - only getting between 2.5 at idle and 5 volts when slightly revving the engine (AC) where I believe there should be a minimum of around 20 at idle

My assumption from all the above is that my alternator is knackered ( not unheard of on VFR according to other forums I have read) and has made the RR work overtime and coils know possibly also be knackered.

[Dan505]

I have recently replaced a RR and generator after tracing a non running bike for two months! No expert by a long way but certainly know enougj, where you based, can take a look? Google Electrosport and follow their guide

[Dan505]

Also you may get continuity but that may mean the wires have melted together if coils have overheated

[Berniebloke]

Thanks Dan

I am pretty convinced now that both RR and alternator are kna*****d. Just wasn't sure on the testing I was doing but after checking the output direct from the alternator am now pretty sure I have found the problem. New RR and alternator it is.

[Berniebloke]

I have recently replaced a RR and generator after tracing a non running bike for two months! No expert by a long way but certainly know enougj, where you based, can take a look? Google Electrosport and follow their guide

Dan - can I ask where you sourced the parts from please ?

[Dan505]

Different bike Bernie. Google is your friend but there are loads of generic ones on ebay

[Dan505]

You may not really need a new alternator could just need the wiring sorting