Trying to fix my sons 52 reg R6 electrical problem

[bob_rich]

Hi Folks

I am retired electrical engineer and am struggling to help my son with a electrical problem. The bike is a ( in the UK) a 52 reg R6 and the problem is that when it is taken on a long run it cuts out and it transpires that the battery is totally flat. This occurs even when only side lights are on. With a headlamps on the battery runs down even quicker. We have tried a number of things including going through the workshop manual to check the resistances of the coils in the Stator Coil Assembly all seem within specification at around 0.27 ohms when cool. We have also removed the alternator cover to reveal the Stator Coils and they all look fine no sign of burning or blackening of any coils. On start up the alternator does appear to charge the battery but we get a tad less that 14V at 5000rpm.
It was around 13.6V but was clearly charging. We have also replaced the Battery and the Rectifier Regulator module but no change in the problem.

I also rigged up a test to feed the Stator output into a 3 phase rectifier with a 2 off 55/60W car headlamp bulbs as a load and when cold the unit gave 14.4V across the bulbs. And this occurred when the engine temperature was indicated as around 84oC. With this test of course the battery was not being charged but the voltage held at 12.4V and fell to 11.7V when the full headlights were switched on. This suggest the battery is not in too bad a state.

So what next ?? any ideas or experiences would be much appreciated!! Cant believe that someone out there has not had a similar problem.

Thanks in advance Bob

[Aj2012]

Does it have an alarm fitted?? Or any other extras that could draw current?

Strange that it’s at temperature and you say you have replaced the coils. Coils, as I am sure you will know, can break down at higher temperatures. That was my first thought when I started reading here.

Sounds like something in the charging circuit is failing and your battery is good, the most intensive work the battery does is to start the bike, the charging system or stator does the bulk of the work from there.

Strange one and am sorry that I am not much help. If you do resolve please post and let us know. Interested to find out the resolution.








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[Boz]

As it's an older bike these type of issues do crop up. Look out for shorting or frayed wiring in the loom by checking for continuity, check all earth connectors are ok, and look at connector blocks for arcing and/or corrosion if you haven't already done so.

[Moise]

That does sound like the reg/rec from the symptoms. What did you fit as a replacement - new or used, OEM or aftermarket?

I would suggest fitting a voltmeter so that you can see what's happening during a ride. Doesn't have to be permanent, maybe a small DMM taped onto the triple clamp.

[polar]

I had a very similar problem on my 99 R1 - Battery was OK, not new, but more than acetable. Charging was very similar to yours just a bit down but not bad.

But when i went for a ride with the headlights on after i had been out for a while the dash lights started to go dim.

In the end i cleaned every block connector with Wurth Terminal spray (i had already sprayed them with a normal cleaner but Wurth has an acid in it) every time i sprayed the terminals the charging voltage went up a little, in all i sprayed them all 3 times to get the charging spot on. It must be noted the terminals looked clean to the eye before i started spraying them but the acid /dielectric spray worked so they must have had a small resistance in each connector that just built up.

I also replaced the battery for a decent Yuasa, like i say the original battery was okay but not the best make and down a little.

Since i have done this the charging remains spot on and the new battery remains fully charged also the dash lights remain bright however long im out.

[bob_rich]

Hi All
Thanks for the comments. I will try and comment on each of them.
It does have an alarm and it also stands at my house while son is away at work. I do float charge it . I monitored the current the alarm takes and work out the amp hours that it drains the battery. Using a Timer and battery charger I then give it a short burst each 24 hours to fully top the battery up and that seems to hold the charge OK. So generally it will start OK.

We did not fit new stator coils but we took of the stator cover unit and inspected the coils and they did not look too bad. We then put the original assembly back and have a couple of times checked the resistances of the coils and they were OK. However you have given me an idea what if one or more coils are shorting to earth ?? I will have to look at that possibility. I am not sure if the Stator coils have a common connection to earth so I will need to check that out. Perhaps somebody knows how the coils are connected and do they have a deliberate connection to earth ??

regarding the regulator my son purchased a new one off the web I will check with him the details of where he got it. On fitting the problem was unchanged.

we have seen pictures on the web of burnt out connectors but so far we have not seen any issue with that on his bike. If the battery is charged up most electrical seem to work OK until the battery finally gives up after a long run

A DVM tapped on to the handle bars monitoring what goes on may help. If I do this I will try and fix it to read the battery current rather than volts which should be +ve say when charging and -ve if it is supplying the power--which It should not have to the alternator should do that

cleaned contacts sounds an interesting one I will certainly check that out I use contact cleaner for some of my electrical repair jobs sothatmight be very worth while

Generally is the R6 charging system a bit underpowered ? what do other users think?

Thanks for the interest and keep the ideas coming !!

Bob

[polar]

I do know the early R1s do suffer from poor charging and wiring gremlins that can be cured by a decent clean of all the terminal blocks. The R1 wiring was hardly up to the job 20 years ago and now 20 years on its even worse as you would expect.

I suspect your 02 R6 may just be in the same boat so every little bit of extra resistance in the charging wiring may be enough to cause problems.

I have also read that some of the new reg/rec out there are pretty poor.

[bob_rich]

Hi All

Thanks for the suggestions. I am pretty sure that the stator coil arrangement does not have deliberate connection to ground (chassis -ve of the battery)
so I am going to check the insulation of the coils to ground. While the connectors are out I will give them all a good clean with contact cleaner as well.
when (If!) I finally sort it will post what I have found

thanks for all your help--any other ideas pleas let me know

cheers

Bob

[jompy]

Welcome in
Hope you get it sorted , I'm crap with electrics so I'm no help at all sorry

[Moise]

Hi All

Thanks for the suggestions. I am pretty sure that the stator coil arrangement does not have deliberate connection to ground (chassis -ve of the battery)
so I am going to check the insulation of the coils to ground. While the connectors are out I will give them all a good clean with contact cleaner as well.
when (If!) I finally sort it will post what I have found

thanks for all your help--any other ideas pleas let me know

cheers

Bob

The stator is 3 phase. One end of each winding is connected together, so you see the total resistance of 2 windings with a multimeter connected across 2 of the wires.

The usual failure mode seems to be that the windings overheat, then the insulation fails and shorts to ground.

[bob_rich]

HI All

thanks for the other comments. We set up with a external battery that was in a good state of charge and planned to see if we could measure the current flow in and out of the external battery. The external battery was from a car and so had plenty of umph . However the engine was difficult to start and when it did start it popped and backfired and so we now think that one or more of the cylinders is not getting a spark. We let the engine cool down in case it was a fouled up plug but no luck it now will start but runs very lumpy and backfires. So we are going to strip down the machine more to get at the plugs and coils to test then out.

with regard to the original problem . I note the the alternator uses a permanent magnet to for the field which rotates , (I assume) on the crank shaft
could this magnet have lost its strength?? with permanent magnet motors this is a quite common problem.

Any way it might go quite for a bit but we don't plan to give cup on it! Any further ideas and any pointers regarding the suspected missing spark would be most welcome

cheers and thanks

Bob

[Moise]

There are 2 coils each firing 2 cylinders. So if it's dropping one cylinder, then you're probably looking at a carb issue.