mechanic doubts...

1998 VFR 800

Has been very good up until now, finding small faults no one else could find. But now he thinks my brand new (maybe 30km on it) Shindengen FH012AA R/R is the cause of my lights dimming when he pulls the breaks :crazy:

It puts out the proper volts (13.5-14.3 between idle and 5000rpm) His main reasoning is that the original R/R had two grounds and two positives that went straight to the harness. When the FH012AA was installed, only one positive and one negative were installed direct to the battery (nothing to the harness).

What else should be looked at before the R/R to solve the lights dimming when breaks are used? Or is that normal? The battery is also brand new.

When I drop by his place tomorrow morning I will be able to see exactly which lights dimmed and by how much.

 

Well, um, welcome!

 

Thanks Had an account and for some reason can't login, so made this one.

 

At idle, if set on the low side, this will be normal, as long as the dimming is just minor. Check the RR output at idle and increase it until the voltage is about 13.5. Or you could ignore it, if you don't notice it while actually riding.

 

That is what I am planning to do, unless the dimming is significant. From what I remember when I tested it before, my idle was at 13.5v (idle is approx 1000-1100rpm) unless he changed it.

 

Ok just got back...

With NO tail light bulbs plugged in, no issues at all. When the break light bulbs are plugged in, the bike sounds like its running out of gas at idle & if the breaks are pulled at idle it dies. The mechanic somehow thinks replacing the R/R with a stock Honda one might fix it. His reasoning = that the monitor wire off the R/R goes to the engine stop switch, and the Shindengen FH012AA has no monitor wire. What do you guys think?

Ps: He also got offended when I suggested that soldering connections is better then him making new plastic connectors (if the R/R is replaced).

 

You'd think that he'd prefer to solder...hell, it's almost as easy.
Hope things pan out for you soon.

 

Does switching to hi-beams affect anything? The draw from them would be greater than the brake /tail lights. If not, I would suspect a problem with the brake lighting, or maybe a wiring/switch problem on the right grip. Does the foot brake create the same snag?

A good solder joint is better than any connector.

 

You might consider tapping into the green ground wire on the r/r and connecting that new wire directly to the negative battery terminal.

 

^ you mean run a 2nd ground wire to the battery from the r/r? (the ground on the R/R is already on the battery)

Found out today that every light bulb in the bike (headlights, signals, break lights) are ALL over voltage from stock (some not by much). Will be replacing all of them then going from there. No idea on the hi beams or rear pedal.

 

Pictures of some connectors mechanic found, also narrowed problem down to the running light circuit
*the cut small green wire was done by him, to ground that circuit elsewhere to see if that solved it*
The problem is somewhere in the circuit for the running lights, because as soon as any light is plugged into those sockets and turns on (the running light) it goes from 14.6v charging to 15v.

any ideas?

 

Sounds like there is a big draw on the charging system. Yes it could be the R/R not working properly or the wrong one. One tip though. The mechanic should learn how to take the prong out of the connector properly instead of cutting wires. I would measure the output of the stator when not plugged to the R/R first. If fine then I'd swap the R/R with a known good one and go from there. The R/R may be able to control the voltage but not the amperage. Low amperage will do what your experiencing with the lights, dim. IMO

 

I dont have a schematic for your bike, but on the 6th gen our tail lights are protected by a simple diode pack. If this only occurs with a bulb in any one socket back there then I would look to see if you have a diode shorted closed(open would be no light on that socket). The purpose of these diodes is for running lights to be on and when you press the brake or turn signal you get the disired effect with out loosing the tail lighting at the same time. These diodes are so reliable that most mechanics never think of them and some have dismissed them from even being on the vehical. Its a simple part swap test/part remove and then test that could save your r/r from becoming a working paper weight.

again on the 6th gen, honda uses dual positives and dual negatives plus frame grounding because it is cheaper than buying another size (proper size) of wire for that part of the harness. remember two 14awg wires in parralell dont make a 12, but make a something between an 8awg and a 10awg.

it wouldnt hurt to try an oem R/R but i would want a solid explaination of why it has come to that part and would want to be there to witness the change and testing. if you get the " its the last thing to be checked/changed" line then i would consider an new mechanic, unless you have changed everything else.

your light bulbs are supposed to be 15v bulbs, this is because at cruising speeds your r/r should be making 14.2-14.6 depending on load. since your r/r controls voltage not amperage and your load is just a resistance that only varries when you make and electrical change, you can control amperage by adjusting the voltage, higher voltage means less amperage needed to do the work your asking. and you can actually figure it out using simple ohms law and an approximate value for your battery resistance (about 20 to 200 ohms depending on charge state is normal, DO NOT TRY TO MEASURE THIS! it will kill your meter). to prove this, on 6th gen we have a whole 500 watts (roughly volta X Amps) at the stator outputs, r/r at 5500rpm outputs 14.4 on my bike with the high beams on and rad fan running(just about peak load, only brake lights left out to make 80%load) this leaves me with 34.722222 amps to do everything so take 80% of that or 27.7778A and you only have 6.94444A to charge your battery if its low, run accessories and you will need about 2A for the brake lights if they are needed, dont forget losses in your r/r as it turns electricity into heat when doing its job. this can be measured by placing a ammeter between your r/r and battery to get an accurate reading, use a proper inline ammeter and not the mechanics fluke as the only go to 10A.

 

It happens when a bulb is plugged into any one of the four sockets. There is a R/R from an '01 on it now, got it for cheap so was worth trying. Still have the aftermarket as a spare.

 

Ah. Well I think he is just going to try and bypass the running lights somehow, the bike has been in his shop since mid November. If bypass does not work I need to order a new harness

 

If the charging voltage going up to 15V is your only problem, put it back together and ride it. The specs actually allow up to 16V. Just keep an eye on your battery for signs of over charging, but I don't think it will be a problem.

If it is still stalling at idle and the new ground didn't help, you're going to have to meter each wire out, until you find the abnormal resistance that's causing the excessive load.

 

No more stalling at idle which is a good thing. What would signs of overcharging be? I keep reading that any V over 14.3 is bad for it so 15v constant cant be any good.

Ah...this guy has been riding bikes and working on them for about 30 years. Was hoping he would be good at this. Am only letting him work on it because he views it as a challenge, and the labor is nearly free.