Was planning to rock up to work on the bike this morning, got organised out onto the street turned the key and nothing. Ignition lights on but enough juice to turn the engine. Ok the bike doesn't sit on a trickle charger when it's not in use, but surely a weekly 60 mile blast should be enough to keep it charged? Or maybe not..
how olds the battery? is the earth connection good/recently cleaned ? reg rec wires etc? and those sort of questions, stuff does move and deteriorate over time.
Battery's are a bit pot luck, mine is three years old and as good as new my son has the same make of battery and has just replaced it at two years old, his held a full charge but when put under load (starting) it dropped to 4.5 v. Steve
Hey guys something is seriously wrong here. Removed battery and it is devoid of any electrolyte - in all chambers. Nada. Zilch. How can this be? Ok I've never topped it up but surely a 2 year old battery shouldn't run dry like that?
No leakage. How can I resolve overcharging, is the cause likely to be the rectifier (which was replaced about 3 years ago from the original model which failed) ?
When you get it running check across the battery terminals with a multimeter, with a few revs it should be around 13.5 to 14v if it's much higher then it's over charging. Steve
You're not alone....the battery on my 750 monster boiled completely dry too....!!!! Almost certainly reg/rec failure, as was the case on my bike......and many other monsters, its a common failing and there's loads of info on the UKMOC site. For peace of mind, its probably worth checking out the complete charging system, ie alternator, battery, reg/rec and associated wiring. In particular, the cheap white plastic multiconnector from the alternator seems to be a weak point and often melts....a recommended mod is to cut it out and hard wire the reg/rec using solder or (good quality) butt crimps, but it needs to be a good connection which doesn't cause extra resistance. Some say that the yellow alternator wires themselves are undersized. Check that they're still supple and haven't gone brittle. Electrex produced this flow chart for checking the system..... https://www.electrosport.com/media/pdf/fault-finding-diagram.pdf Many monster owners fit Electrex replacement reg/recs too.....a tad cheaper than std and possibly more reliable. Alternatively you could graft on a Shindengen, mosfet type, reg/rec which is claimed to be much more reliable. Again, there are details on the UKMOC site .....look for "fried reg/rec" or somesuch. Reg/recs work by converting the excess charge to heat and dissipating it through their cooling fins. Dunno where the reg/rec is on an SS, but they're below the fork yoke on most monsters, where they get lots of cooling airflow. Yours may be under the seat where it dissipates its heat less effectively. At one point my battery boiled off so much gas that it blew off the battery filler caps !!! I was stationary at a junction, blipped the throttle, and heard the caps hit the bottom of the fuel tank. All's been well for a year or two now, since I fitted the electrex replacement and hard-wired the multiconnector. Though I'm still a little wary.
My Reg/Rec is mounted where all the carbed SS ones should be...below the bottom yoke on the front of the frame. Mine's an Electrex RR51 replacement...... Not had any trouble with it in 5 years touch wood...(apart from not being properly wired by previous owners) Considering the battery is a conventional cheap Yuasa lookalike, and probably over six years old, I have charged it twice and topped it up twice.......The battery monitor always shows red when switching the ignition on, but the bike has always started and has enough juice in it to spin the engine for much longer than normally needed to start the bike (found that out when I had knocked the Off/Run/Off switch). It could be that one cell in the battert is dying, hence the red light, but as soon as the bike is running the light turns green....even on tickover. I fitted the yellow wires with large diameter / heavyweight crimp connectors and made sure they were a tight fit.....ends sealed with silicon gasket mastic. I also made sure the ally plate behind the R/R was clean and making good contact. A mate of mine has played around with his R/R and has a defunct R/R fitted behind the real one for more cooling.
Awesome info many thanks! I think my replacement reg/rec was Electrex but I'll check the paperwork and go through the fault finding process tonight, time allowing..
You can normally tell an Electrex RR51 by the way it has been wired......(If it hasn't got a sticker on it) It should have it's own positive and negative leads directly to the battery. It is supposed to eliminate the big 30Amp fuse by the battery (which all that does is protect the OEM Reg/Rec) so there is no reason why it can't be used as the positive, even though the RR51 is supposed to have it's own internal fuse (un-replaceable). So to stop the RR51 fuse from failing, I guess you can safely use the old positive wire and could stick a lower amperage fuse in the big holder.
The Electrex that I fitted after my battery boil-up was a RR53, which just plugged into the harness as normal (yr 2000 M750). That just had two multiconnectors, one to the alternator (3 yellow wires....3-phase alt) and the other to the battery etc (4 wires, can't remember the colours offhand ....red, green....?). The big fuse is still there. At first I used both the std multiconnectors, but a few months later (on a particularly hot day, as it happens) I had a second failure when the connector with the yellow alternator wires melted and charred to a crisp...!! Amazingly though, when I cut out the damaged connector and rejoined the wires, the system checked out perfect and has been fine for a year or two since. The butt crimps that I used to join the yellow wires were small, and lined with hot-melt glue for a totally sealed connection. These..... 10 X RED HEATSHRINK BUTT CRIMP TERMINALS | eBay I went for the smallest I could find, with a vague notion of minimising any change in resistance at the connection. But note...... electrics are not really my forte. The bike recently did a trouble free week in Italy with temps well into the thirties...so I no longer fret about a repeat burnout on a hot day.
Best to solder the wires........other than that, use the largest connectors to minimise resistance in the wires.
Ok well I put a good battery in from another bike and got the meter on it, reading about 13-14v rising to 18.5v with slight revvage. I don't have time to go through the Electrex flowchart yet, try and do that at the wkd.
I have had two Electrex units fail in two years with all connections soldered, perhaps bad luck I don't know, I have since fitted a Shindegen Mofset unit with no problems, this unit has a thermal cutout so if it overheats it just shuts down until cool and then continues to work without fault. An upgrade I would recommend. Steve
