Out of Ideas

This'll be my first post here, so I'll try and give a little background.

I bought myself a 3rd gen vfr750-fm a few months ago, having recently passed my test, so it's my first bike, and a hell of a place to start out... It's outwardly pretty scruffy, having had various bumps and scrapes over it's life, but mechanically it's spot-on.

I was pleased to find something that I fit on comfortably (being 6' 5" can
rule out a lot of bikes!) and the fact that it's as good to ride as it is meant it didn't
take long before I was feeling pretty at home on it. In short - I love it!

All this means that it's all the more frustrating that I can't ride it at the moment.

Having done my research before buying the bike, I knew about the Reg/Rec problems well enough, and while I was talking to the previous owner before buying it, I found out that he'd gone down the route of fitting a CPU fan to the R/R heat-sink fins, and had never had any problems since.

So the first time I take it out aver buying it (and also my first ride after passing my test!) I get about 40mins up the road, and it frys the R/R and dies on me... Turns out the fan the previous owner had fitted wasn't wired in, and so wasn't running, just blocking all the airflow to the R/R heatsink.

Not the greatest of starts, but you've gotta take these things as they come I guess.
Wanting to get it back in action asap, I "borrowed" the R/R from my dad's Varadero, as he wasn't using it at the time, and it turned out to be the same part, and later replaced his with a new one.

Now I new I was on borrowed time with the R/R liberated from my dad's Varadero, as without any modification it was bound to blow sooner or later, as they're known to do, but I guess I had figured I had a bit more than the 1000 or so miles that it lasted before that one overheated and died, leaving me cursing myself for not doing anything to sort it sooner.

So needing another new R/R, I decided to opt for using one taken from a 2006 Yammy R1, as many people seem to have successfully used these as a means of fixing the problem, Including a few on this site!

Having trimmed the comparatively enormous cooling fins down a little to fit the thing in, and shuffled the rear brake fluid reservoir back a little to make room for it, it was
working as hoped, charging the battery correctly, and barely getting warm to the touch, unlike the previous oem part, that rapidly got too hot to touch!
Perfect, I thought. Problem solved.

No such luck. After a 20min ride, and having briefly stopped, I discovered that I didn't
have enough charge in the battery to turn it over - It had popped the Yamaha R/R. It didn't even seem to have overheated it either, barely feeling warm when I checked it after it blew.

So... 3 Reg Rec's later, and I'm out of ideas. The bike's been sat outside my door for the past week, and it's killing me not being able to ride it, but I'm stumped. Is it possible that when the 1st or 2nd R/R went, it damaged the alternator somehow, in such a way that the potentially damaged alternator then blew the R1 R/R in the space of a 20min ride, or could there be something else that's causing it to eat R/R's more often than I change my socks?

The alternator output and resistance between the terminals seems to check out against the readings the manual suggests it should give, so it would seem to be ok, but electronics has never been my specialty, and I've no idea weather there could still be a problem with it that I'm not able to spot with a multimeter.


Any suggestions would be very welcome, (in layman's terms if poss' please!) as I'm tearing my hair out not being able to ride it!

 

Buy a new battery, having a weak or dying battery will put strain on your R/R...

 

D'you reckon excess resistance from the wiring harness could cause it to wreck a new
R/R in 20 mins?

 

A friend of mine had suggested the possibility that the battery might be the problem, and it isn't fitted with a particularly expensive one, but it is almost brand new, so I wasn't sure that it could be the source of the problem given how quickly it's been going through R/R's, but perhaps a better one would be well advised...

 

Nope, I haven't. forgive my ignorance, but what sorta issues with it should I be looking for?

 

Nice one, I'll check it out. Thanks for the help.

 

+1 on the wiremybike vfrness, my 5th smoked the connectors off the R/R 200 miles from home, so i soldered everything to avoid connector meltdown. Several weeks later it blew the main fuse. I bought the VFRness and the ricks motorsport rectifier, put a PC fan wired to the plate light on it and it has been spot on for close to 2000 miles.

 

Just had another look at my wiring, and the starter relay connector is in a woeful state. The rest is not exactly a shining example of perfection either. I guess I'll be ordering the VFRness then... noticed the guy also sells a version of it modified to fit a late-model R1 R/R instead of sticking with the Honda one. think I might just go for that and see where I get.
Thanks for the pointers, I'll let you know how it goes!

 

just trying to add some input here, not how far youve gotten or if these were are ready covered... these are all great ideas youve gotten so far...

other things to look into are did the wire harness recall get done. take all the electrical conections that you can find apart, clean them, pack them full of dialectric grease and put them back together. clean and inspect all the ground wires/ battery terminals. test out your stator(not sure about your specs) with my 07 you are supposed to be putting out about 20 vac at idle and about 60 vac at 5 grand. also i never really figured out the continuity but measure the resistance between the 3 stator wires and each other and also with the ground.
also pick up a vfrness(i know you know that one)...
check the whole factory wireharness to see if there is any shorts, or frayed parts that are rubbing/ making contact with ground. i can think of any thing else right now. but hang in there. i had to do a complete electrical shake down on my bike too and it sucks. but these are awesome bike once you get the electrical kinks sorted out.

 

the only thing that can be left is over burden on the reg/rec. a simple relay stuck closed can cause the r/r to be overburdened and cause them to "blow" not saying this is your problem, but check the load amps from your r/r before it gets distributed. or even that batt sense wire. if it doesnt show batt volts-.02v then the r/r may be off completely, I scratched my head on my 07vfr as I was checking connectors and one pin got pushed out causing me to have intermittent charge issue. just a thought for things to check.

zen

 

Hey - so, I've had to leave this post for a while 'cos i've been waiting for the VFRNess to arrive, but I eventually got it today.
Bought myself a new starter relay too, as although the VFRNess comes with parts to replace the starter relay plug, the terminals on my original (19year old!) relay were a bit past the repair stage. It was still working (somehow...), but I didn't really wanna take the chance.

Just wanted to ask anybody that's fitted a VFRNess to their bike for a bit of a pointer. Mechanics I can live with, but electronics have always troubled me - gimme a spanner over a soldering iron any day...

The new harness comes with new wires to both battery terminals, but should I be fitting them to the battery along with the original connections, or leaving the original battery-terminal wires off and just connecting the new ones?

Stupid Question perhaps, but as I say, I've always been a bit lost with electronics. Bit of a shame really, as although the bike's wiring is in a shameful state, mechanically it runs smooth as silk. Still can't quite belive my luck to lay my hands on such a sweet piece of kit for my first bike!

 

I'm like you - I love wrenching but hate wiring. Even with the VFRness, you want as many paths back to ground as possible - I left the original ground wires in place on both kits I've installed. It might be worth getting some Deoxit to clean the corrosion off all the terminals and connecting surfaces on your bike. Separate all the connectors, spray them with Deoxit and be sure the female blades have a firm grip on the male ones. You can find Deoxit on-line (Am*z*n.com) or maybe there's an equivalent product in the UK. Check any electronics supply store. Pay special attention to the main ground where the harness attaches to the chassis. Follow your negative wire from the battery and you'll find it where it attaches. You can also use a product called Noalox to prevent corrosion from building up to start with. It also promotes conductivity. Good stuff. Keep at it and you'll sort it out.

 

I will say it one more time.

The purpose of the aluminum finned R/R is to regulate by giving off excess energy as HEAT.

When you cut off the aluminum fins it reduced the total cooling area of the fins.
It is SUPPOSED TO GET HOT at times.

But like others have said you need to check all connections and grounds.
Matter of fact the worst corrosion potential will be between aluminum connected to copper.
Most motorcycles have steel frames and will have a little less corrosion problem than a frame made with aluminum and copper grounds attached to it.

Make sure there is a ground going from the battery to the ENGINE and a ground going from the battery to the FRAME.

 

Let us know how you get on with the new harness