110 replies to this topic

[Grendel]

Regulator cooked itself recently and one plug cap had high resistance but didn't change battery after fitting new regulator and plug cap. So going to try new battery and normal plugs since some say Iridium can upset it too but didn't seem to bother it in past.

 

 

Must admit hoping it fixes it and I all in love with it again since at the moment wouldn’t be bothered if it was stolen since fed up with it.

 

Apologies for late responses since don't get post notifications sorry.

Edited by Grendel, 10 March 2023 - 07:30 am.

[Grendel]

 

 

Changed battery and plugs and it started fine then after 5 mins revs randomly dropped and started running rough then came back again then few minutes later back to rough running then back to normal again on 3^rd time it stalled then wouldn’t turn over with lights on. So run it for a bit without lights on but still had the random rev drop and rough running but then cuts out if you put lights on so definitely an electrical fault since both batteries new and old started around 12.5V and 11.8v running.
 

So far, I’ve had:

Main wiring loom rebuild few years ago before the current problems.

Full carbs rebuild twice.

New fuel pump.

New regulator/rectifier.

New ignition coil

New battery

New plugs.

Valve clearance checked and adjusted.

New shims

 

Edited by Grendel, 12 March 2023 - 03:31 pm.

[Lightning]

Have you tested the generator? Had similar with my vfr, kept cooking reg rec.

[Rallyist]

Running voltage should be 13.8 to 14.2 you have a charging problem you need to check the output of the stator when plug disconnected from regulator

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[Catteeclan]

At least you know you def have a charging fault is now.
Stator fault, dodgy reg/rec of something gone wrong with the loom rebuild.

[Grendel]

Reading up about Stator failure seems that may be the culprit after all since has some of the symptoms also it’s the only part I haven’t yet changed.

 

Just fecking irritating that the two expensive mechanics it’s been to did not spot it.

[Snowbird]

Sounds like the reg/rec is actually dragging the battery charge down rather than just not working at all, how about fully charging the battery and taking it for a run with reg/rec disconnected and lights off and see how it behaves, it should run for a while on a well charged battery ok.

Keep local though just in case, and maybe have a voltmeter strapped to the bars so you can see when the battery is going flat.

[Pedro]

I can imagine how frustrating it must be, they're usually reliable bikes, until they're not! I would go with the consensus that its a charging system related problem. You can get those digital voltage display thingies easy enough and I would stick one on,even just cable tied to the handle bar and see what the charging volt is when running. I had a problem with the connector from the stator under the battery tray and I noticed it because the voltage display warned me my charging volts was going down when on the road. If I was to get another bike, any bike, it would be the first accessory I would install.

[fixitsan]

The test for a stator is fairly simple. It has three white (usually) wires, which are the three phases.

With the bike running and a voltmeter set to the AC volts range, you should see which phase is faulty as you measure between phase and ground, definitely need to see over 16V at idle and over 20Vac when revved.

 

I think I have an old stator, if i can find it you'ld be welcome to give it a try

[Catteeclan]

The test for a stator is fairly simple. It has three white (usually) wires, which are the three phases.

With the bike running and a voltmeter set to the AC volts range, you should see which phase is faulty as you measure between phase and ground, definitely need to see over 16V at idle and over 20Vac when revved.

 

I think I have an old stator, if i can find it you'ld be welcome to give it a try

Should you not test for resistance to ground and there should be none?

Test the stator using a combination of any 2 wires at a time should get the same (ish) voltage.

Never tried your method Chris. Might have learned something today.

[fixitsan]

Should you not test for resistance to ground and there should be none?

Test the stator using a combination of any 2 wires at a time should get the same (ish) voltage.

Never tried your method Chris. Might have learned something today.

 

Yes you can also do that, a running test would detect shorted coils, which wouldn't necessary leak to ground.

 

Definitely worth checking both

[ChrisG]

If it does turn out to be a generator issue and fixitsan can't find his, have a hunt around the knowledgebase on here.  Someone (probably MarkyMark, Celtic Biker or Matlock) found somewhere that would rewind them when they failed on high mileage 900's

[Studley Ramrod]

Sounds like it could be a bad earth/connection somewhere if the voltage is dropping with higher revs.  Or possibly a current leak. Have you looked at the fusebox and fuses ?  Esp where the wires enter the box.

[Grendel]

Culprit found.

Safe to say the state of the stator coils is what is known as fecked. Probably the mix of water and oil in the casing over the years probably didn't help.

 

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[Snowbird]

Hopefully a new stator will solve you're troubles so you can fall in love with it again.

Good job you didn't do loads of other stuff first....

[Grendel]

Hopefully New Stator and it will finally be the bike it should be. Didn’t plan on full electric restoration originally.

 

Most annoying thing is the so-called bike engineer had it for 5 weeks yet didn't diagnose an electrical problem.

[Catteeclan]

Culprit found.

Safe to say the state of the stator coils is what is known as fecked. Probably the mix of water and oil in the casing over the years probably didn't help.

 

Not unusual to see some hot spots, has it failed the test?

[Sphere]

Hopefully New Stator and it will finally be the bike it should be. Didn’t plan on full electric restoration originally.

 

Most annoying thing is the so-called bike engineer had it for 5 weeks yet didn't diagnose an electrical problem.

Hope the so-called engineer didn't charge you (no pun intended)

 

Finding good independent mechanics is hard these days, they're a dying breed.

 

Hope all your woes are now behind you and you can enjoy the bike this summer.

[fixitsan]

Culprit found.

Safe to say the state of the stator coils is what is known as fecked. Probably the mix of water and oil in the casing over the years probably didn't help.

 

 

Looks dud.

Sadly, I've just had a brief look in the garage but can't find my spare, It might be hiding under a pile of boxes though so I'll need more time to look when I'm not working.

 

I think I checked a few stators when my 900 one failed, as well as the 850, also a BMW F650 or F900 also fits but the cables need to be extended and the plug swapped over, which is a bit of a faf if it's not your daily do. I think the 4tx one I had also has a different plug so it would need to be swapped over too.

 

I see there's a few on ebay, starting around £50 for a plug to plug straight swap https://www.ebay.co....:Bk9SR-TciJrdYQ

[dablik]

I may have a MK2 stator !? need to look, i assume it can be used !? even so you'll need to use the wiring from your MK1 as it's without the 3 wire cable, away at the moment until the weekend though, let me know if i should have a look for it.