Rough running R12S

[dave the german]

This has really got me baffled as it was running reasonable - lower stick coils maybe? just going to be a process of elimination, but I can see it being expensive

There's an unplug stick coil, see if it runs worse, if it did that coil was fine - procedure you can try when you experience the bad running. Very (un)scientific.

Thinking being that if a coil isn't working, and you disconnect it, it shouldn't have an impact on the idle whereas a working one being disconnected should impact. I think I even took mine for a ride with all each coil as well as both the lower ones disconnected.

I see what you're saying - mine just seems to run OK and then when I think it's OK something else goes wrong. After speaking to Hilltop and doing as he advised and then changing the upper coil pack and cleaning all connectors it seemed to be fine - best idle I'd ever had, plus using the removed coil pack on my BCR and having that run shite, then after the engine warmed up it was the worst it had ever been. At the moment I just don't have the time to keep plugging and un plugging connections. I absolutely love the bike when it runs somewhere near normal but this is really doing my head in

[victorlaszlo]

I think:

If it's heat related = coil issue
If it's random and ignition cycle cures it = stepper motor

Or in worst case a combination (which ended up with although initially it was just the stepper).

If it happens on cold engine then you can temporarily rule out the coils and sort out the failing stepper motor.

Having fixed the issue with a fresh used stepper motor when the engine is cold but it keeps occurring when warm and you can't ignition cycle it away = coil also failing.

--

Side note. Interesting is that since I was a kid with my first mopeds in the countryside the solution when your moped wouldn't start when warm was always the coil (or possibly the condenser) on the stator plate, and now with bigger bikes it's still the same, just that since they have more coils than one they won't completely die but just run poorly. Happy at least that there isn't some unidentifiable batch issue with the throttle bodies which someone speculated about on PelicanParts but due to normal components failing...

[dave the german]

As the problem has been ongoing with each "fix" failing I do suspect a combination but this is the first time it has happened when warm - I suppose it could be components failing as time goes by. I think it's going to be a case of take off coil packs when the problem occurs and go from there

[boxerscott]

Tough luck Dave. Wish I could have something positive to say to help you guys, are your bikes standard? have they been fitted with after market fuelling gizmo`s?

Chris

[dave the german]

Tough luck Dave. Wish I could have something positive to say to help you guys, are your bikes standard? have they been fitted with after market fuelling gizmo`s?

Chris

Completely standard - does have an Akrapovic but that is a BMW accessory. Tick over and pick up were the best they've ever been when I fitted a new primary coil stick. Fitted another so I know it has 2 good upper coil packs and will try and fit the lowers off the BCR if the connectors are the same/adequate cable length. Interesting what Victor said about low fuel tho - there is a fuel strainer in the tank might be worth pulling that out as mine started running badly at the same time as it got warmed up/fuel light came on - I'm not giving up on it yet as I love the bike!!

[boxerscott]

Tough luck Dave. Wish I could have something positive to say to help you guys, are your bikes standard? have they been fitted with after market fuelling gizmo`s?

Chris

Completely standard - does have an Akrapovic but that is a BMW accessory. Tick over and pick up were the best they've ever been when I fitted a new primary coil stick. Fitted another so I know it has 2 good upper coil packs and will try and fit the lowers off the BCR if the connectors are the same/adequate cable length. Interesting what Victor said about low fuel tho - there is a fuel strainer in the tank might be worth pulling that out as mine started running badly at the same time as it got warmed up/fuel light came on - I'm not giving up on it yet as I love the bike!!

I remember changing my fuel filter on the bcr after 24k cos that was what the service manual said. Been honest having an ally tank things were spotless, I reckon the fuel filter is not your problem. Those in line charcoal filters can take some stick. Fuel starvation/filter issues generally affects higher up the revometer readings I would have thought. Persevere and let us know how you get on.

Chris

[victorlaszlo]

My thinking is that:

1. If the problem is there all the time it can be a broken coil.

2. If the problem is there ONLY WHEN HOT then it's a malfunctioning coil.

3. if the problem is there randomly COLD AND HOT then it's a stepper engine.

And then of course you can have any combination of the above.

Coils can be checked (kind of) by unplugging them one and one when the problem is present. If you disconnect a working coil it will run worse, if you unplug a non working coil then it will make no difference to the running (assuming the problem is present).

[dave the german]

My thinking is that:

1. If the problem is there all the time it can be a broken coil.

2. If the problem is there ONLY WHEN HOT then it's a malfunctioning coil.

3. if the problem is there randomly COLD AND HOT then it's a stepper engine.

And then of course you can have any combination of the above.

Coils can be checked (kind of) by unplugging them one and one when the problem is present. If you disconnect a working coil it will run worse, if you unplug a non working coil then it will make no difference to the running (assuming the problem is present).

Thats exactly the problem with plugging a computer in - the conditions for a fault code must be present but just cos the computer says there are no faults doesn't mean there are no faults!!

[victorlaszlo]

Mine shown only that a coil had failed in the past, I think you need to have a significant part failure for it to show up, things such as steppers not arriving at their positions even if they believe they have, not sealing properly or poor performing coils probably isn't noticed...

[Droptarotter]

If the problem is a stepper motor, how do you determine which side it is?

Good right up guys!

Cheers

[victorlaszlo]

If it's completely dead then you can feel that it's not working by putting your finger on it. Possibly other mechanical problems with it could be determined this way.

If one side's cylinder is running rough perhaps you can hear it as well, I'm not sure whether or not an IR temp reading would reveal anything though...

If the problem is a stepper motor, how do you determine which side it is?

Good right up guys!

Cheers

[Droptarotter]

If it's completely dead then you can feel that it's not working by putting your finger on it. Possibly other mechanical problems with it could be determined this way.

If one side's cylinder is running rough perhaps you can hear it as well, I'm not sure whether or not an IR temp reading would reveal anything though...

If the problem is a stepper motor, how do you determine which side it is?

Good right up guys!

Cheers

Thanks;
It's been a while since I tried doing anything to diagnose my problem. I can cycle mine with my GS911 and both steppers do cycle. I have not removed them to see if they are cycling fully/properly though.
I think it might be tough to "hear" if the steppers are both working as there is a fair amount of engine noise, but its a good idea!

I'm not sure when I will have a chance to get back into this, but will post any details I find.

Cheers

[dave the german]

Well, update on poor running - hopefully getting somewhere at last - don't want to post too much as I don't want to tempt fate!!!!! but, there are internal problems = mucho greenbacks to hand over (well plastic really). Once it's properly sorted I'll give the results

[boxerscott]

Well, update on poor running - hopefully getting somewhere at last - don't want to post too much as I don't want to tempt fate!!!!! but, there are internal problems = mucho greenbacks to hand over (well plastic really). Once it's properly sorted I'll give the results

One would not expect that from a low mileage boxer Dave, tough luck, hope the repair bill is "palatable"

well persevered

Chris.

[Droptarotter]

If my bike still has the problem in the springtime, I'll try swapping one stepper motor at a time out of my HP2 to see if I can find the culprit.
I did check the parts fiche and HP2/12S steppers have the same part number.

Cheers