Faulty reg/rec, battery, or both?

Could be wrong but the diode test is just for the rectifier function not regulator. 4 diodes are used as one way filter. Id do as the post above describes

OK, with a good battery:

Off 12.78V
Ignition + lights 10.9V
Idle + lights 18.8V
5000 rpm * + lights 8V

Stopped testing at this point as don't want to knacker this battery too. Is it safe to disconnect the reg/rec, then start the bike and test the alternator output?

* guessed at 5000 rpm as tach needle still stuck

[Geodude]

Worth a pm to Yc or wait and see if he see's this before you go any further if your not sure what to do next. Looks way wrong to me and i cant remember if i disconnected block to do alternator test.

[TamSV]

You'll be alright. Disconnect the connector with the 3 yellow wires and test in pairs on the generator side of the connector.

The battery won't be charging while you're doing this but it'll only take a minute.

Thanks. All pairs read about 25V at idle. At my guess of 5000rpm they all read about 60V, though my guess was probably a bit low. In any case at a given amount of throttle, the readings across all pairs are consistent.

[TamSV]

From memory you want to see over 70V at 5k revs. Easy to underestimate the revs when you're trying to hold it at 5k and are conscious of the noise you're making, so your low readings may be nothing to worry about.

Did you mention to me at Aviemore that the reg/rec had been changed recently? I might be thinking of someone else (it was an SV rideout after all ).

If it's been changed, it might be worth checking some other things before writing off another one.

[yorkie_chris]

60V will be reet. If a coil is burnt you will get 60V/60V/3V or something like that so don't worry.

Tam - yes it was me, and yes, reg was replaced sometime between 1 and 2 years ago.

If the alternator is good but I'm getting the really high idle voltage and really low 5k rpm voltage, then it must be the reg/rec yeah?

And if so is it a RR85 I'm after. I saw on Geodude's thread that TV recommended one from a cbr 600 re.

I went through 2 standard R/R in my SV before doing the mod to a CBR-RR R/R (yeah I know!). All the information you need is in this guide by DEcosse - http://eviltwinsbk.com/forumz/index.php?topic=276.0

He explains what to test, what to do and how to prove it works. For someone else's experience with an SV check here: http://forum.svrider.com/showthread.php?t=106041

I am now using the CBR reg, in a better place, with my own beefed up wiring and it's running like a dream!

Good luck!

[TamSV]

Originally Posted by Terah

If the alternator is good but I'm getting the really high idle voltage and really low 5k rpm voltage, then it must be the reg/rec yeah?

Sounds like it. As far as what the current thinking is on the best replacement I'm not sure but you'll find it all with a search here or on the links above.