Symptoms for faulty voltage regulator ?

[GORILA]

I am trying to sort out the very erratic running of my R1100GS. It will not run under load, the longer it runs it becomes more erratic and quickly stals. I have checked most things and have replaced my air temperature sensor and the oil temperature sensor, with no result. Can anyone tell me what are the symptoms of a faulty voltage regulator. I suspect this may be the cause of my problem.
Any info would be appreciated, before I buy another expensive part !

 

[JJH]

Pardon me but could you not just put a multi meter across the battery set to volts and read what it is putting out? JJH

 

[Roger 04 RT]

Gorila, The voltage regulator doesn't seem likely to cause your symptoms. As suggested above, with the bike at 1800 Rpm, then at idle, what is the voltage at the battery terminals?

 

[Nin]

Sounds like a coil problem.

 

[GORILA]

Just been out to the garage. I get 13.7 - 13.8 volts across the battery terminals with the engine running... what does this mean?

 

[GORILA]

...don't think it's the coil. I replaced that not so long ago and I get an apparent good spark from both plugs

 

[AberdeenAngus]

Just been out to the garage. I get 13.7 - 13.8 volts across the battery terminals with the engine running... what does this mean?

That looks fine. Doubt there's much wrong with your regulator.

 

[GORILA]

I

What would be the symptoms of a failing voltage regulator ? I read somewhere that this could be the cause of rough running...

 

[JJH]

Charging looks fine. I not claiming to be a expert but I'd be checking fuel supply filters or a blocked vent. Unfortunatly you can sometimes go round in circles chaceing a problem like yours and it's hard to resist buying somthing as we convince ourselves that we are at that eureka moment. I've been there. Many times. JJH

 

[GORILA]

You're right there JJH. I first thought it was a failing/ burned out valve. The fault developed very suddenly and pretty quickly, within a couple of days. A faulty compression test reading led to me stripping both heads and lapping the valves and cleaning the valves and heads. I now have good equal compression from both cylinders.
That did not fix the problem with the bike however. My local mechanic suggested I should replace the air temperature and oil temperature sensors. He has had a few older oilheads in recently, with sensor failures. Again this did not solve my problem.
I cleaned out the tank and replaced my fuel filter. I checked the fuel lines by pushing through some skewers. I found no obvious obstruction.
I have swapped over the hall sensor and TPS old but working ones. I have rechecked valve clearances, TPS voltage and cam timing...all are good. It is all a steep learning curve, but I am running out of ideas.
I should have taken t to my mechanic, it would have been cheaper but I have enjoyed tinkering.

 

[AberdeenAngus]

What would be the symptoms of a failing voltage regulator ? I read somewhere that this could be the cause of rough running...

Yours ain't failing.....be told.
Oh ok then......symptoms of a failing regulator would be voltages of below 12v or above 14.4v whilst running.
If you have a scope you might also see excessive spikes or troughs in the smoothed output if one of the diodes was breaking down.
But really, yours sounds spot on.

 

[JJH]

You're right there JJH. I first thought it was a failing/ burned out valve. The fault developed very suddenly and pretty quickly, within a couple of days. A faulty compression test reading led to me stripping both heads and lapping the valves and cleaning the valves and heads. I now have good equal compression from both cylinders.
That did not fix the problem with the bike however. My local mechanic suggested I should replace the air temperature and oil temperature sensors. He has had a few older oilheads in recently, with sensor failures. Again this did not solve my problem.
I cleaned out the tank and replaced my fuel filter. I checked the fuel lines by pushing through some skewers. I found no obvious obstruction.
I have swapped over the hall sensor and TPS old but working ones. I have rechecked valve clearances, TPS voltage and cam timing...all are good. It is all a steep learning curve, but I am running out of ideas.
I should have taken t to my mechanic, it would have been cheaper but I have enjoyed tinkering.

I'm out of ideas myself. Did someone mention coil? Good luck. JJH

 

[AberdeenAngus]

Could be a plug breaking down

 

[Uncle-Fester]

Coil, Plugs, Leads, there's nigh on £200 if you buy new ones.... ouch.

I feel your pain, I'm in the same situation with a clio dci.

Good luck with the fix and let us know when you sort it out.

Failure under load does sound very much like plugs, leads or coil though.....

 

[GORILA]

Thank you gents ! Gives me things to try out over the next few days, regards...

 

[AberdeenAngus]

Coil, Plugs, Leads, there's nigh on £200 if you buy new ones.... ouch.

I feel your pain, I'm in the same situation with a clio dci.

Good luck with the fix and let us know when you sort it out.

Failure under load does sound very much like plugs, leads or coil though.....

I agree, it does sound like an ignition issue.
Weeeelll...lets rule out the coil for now as its a new one.
So I would suggest you get hold of one HT lead and one plug, and try them in each side. See if that sorts it.

 

[Nin]

There should be coil, plug cap and HT lead resistance specs in the workshop manual, that are easy enough to check with a multi meter.

 

[AberdeenAngus]

There should be coil, plug cap and HT lead resistance specs in the workshop manual, that are easy enough to check with a multi meter.

He might find the fault with a meter but I've had some pretty elusive HT faults in the past that I've only found by replacement.
A high voltage Megger might find them but for the cost of a plug and an HT lead....

 

[snaponphil]

Sounds like an ignition fault, generally speaking as the mixture weakens off the engine requires higher voltage to fire the fuel.
Which in turn stresses the components & causes either the coils to misfire or the plugs or HT leads to leak high voltage electric to earth through engine casings or other path of least resistance.
If you haven't changed the spark plugs with a decent socket you can sometimes create a hairline crack (unnoticeable) so perhaps removing a faulty one & refitting (although new) with another faulty one.. (Or even more than one)

Hope that helps a little..
Good luck..

 

[Flipfly]

It might sound silly, but pull ya fuel pump out and replace the U link pipe. I had very similar issues with an 1150 and it turned out to be the U pipe. They are expensive, but if it's never been changed the chances are it could be collapsing under load. Mine looked fine btw. Fuel fliter might as well get replaced whilst in there. Lots of people avoid doing anything in the tank thanks to the tiny studs which can break off if rusted up. Take your time, soak with penetrating oil and they should be fine.