Charging System Fault

Hi guys,

I'm new to the forum, so hi! I've also recently bought a seemingly very nice 1999 VFR 800 in red. I picked it up a couple of weeks ago and the guy I bought it from said that he'd recently replaced the reg/rec and stator from Electrex World (900 miles ago in July 2017).

On my first real outing on the bike, I rode it from about 15 mins, stopped briefly and went back to the bike but it wouldn't start. I left it for 5 mins to call the AA, went back to it and it started fine. Rode it for a little while longer to an underground car park where I left it again and then came back an hour later to find that it wouldn't start at all. The AA came out this time and managed to boost the battery to get it started. Rode it again, the rev counter started going crazy and the bike conked out. AA came out again and recovered me home.

I've since replaced the battery although haven't used the bike much so not sure if it's still playing up. The reg/rec and stator are fairly new and the battery is showing about 12.8V when the bike is turned off.

I've also just run the test on the stator but running the multi-meter off all three wires coming from the stator and getting about 0.6 ohms off each one which seems to be within the specified tolerance. It could well have just been that the battery was old but does anyone have any ideas?

Cheers

 

Welcome to the forum. Many of us think that the 98 and 99 model years are the sweet spot in the VFR 700/750/800 series. You should post some pictures of your new bike in the introductions forum under the general heading.

To the task at hand, Go to the following thread : http://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

DO THE DRILL described in post #9 if you haven't yet.

Be advised that the R/R you currently have is not one that has a good reputation. Even though it may be new, if it were me I would suspect the R/R to be falty.

 

Thanks for the response - I'll have a through through that thread and will post some pictures in a bit!

 

Hi, I'm looking for some further assistance to the original post. I've replaced the battery, had the alternator tested by a mechanic friend of mine and replaced the reg/rec. With the new regrec connected I was getting around 14.2v at idle speed which then drop to around 13.7v at 5k rpm.

I'm at a bit of a loss. Does anyone have any ideas what else it could be?

Thanks

 

What RR did you use, and how did you do the connections?

 

sorry, just read original posting.
Dump that RR and get a good one. There are many second hand ones that are known to be good and can be had cheap.
Yamaha R1 RR is a good option, get rid of the connectors and direct solder.

 

If voltage falls at increased RPM it says either RR or more likely Stator is defective.

For the tests to be useful you must start with a healthy fully charged battery and the tests mentioned in post #2 above have to be done TWICE - once with the bike cold and repeated after the bike has been for a 20minutes+ ride. Why? Well heat related defects can mean that components can test OK when cold but fail when warmed up. Diodes in the RR and insulation on the stator windings can breakdown when hot, creating new paths for current flow which may mean that instead of charging your battery once it warms up it gets drained.

Sorry time for drill part No 2 - post up if you are unsure of the results - you will find the basics of how to do the tests and what they mean further down that very long thread linked above.


SkiMad

 

My voltage dropped when the revs went up so I replaced the rr with a yam r1 one from ebay and directly soldered the yellow wires and fitted a vfrness. A solid 14.4v at any revs for me.

 

I opted for a $40 Ebay "pre-owned" (but genuine Shindengen) ZX10 Mosfet, wired direct (mid connector deleted)

That was in 2010 ....issue free 7 full seasons now (approx 23K miles)