Running crap troubleshooting aid please

[vfxmark]

Injected boxers since mid nineties... finally a problem with the way it runs

06 1200GS approx 35k miles (56k km)
Chain of events: (maybe germane maybe not... you be the judge)

Fast stop tagging rear bumper of a car - bike fell over right side (on fuel reserve)

got of freeway, refueled at filling station of unknown quality - checked bike for signs of damage, etc... got back on expressway and hauled ass to meeting.
Rode home after meeting - seemed OK

Next day bike idles OK but anything over 1/4 throttle stumbles. - load dependent/ throttle position dependent, not rpm dependent.
cold or warm
can still get to 80 mph no prob, just can't twist throttle too hard
charged batt just in case (old batt but no recurrant probe)

took to dealer to check codes etc - no codes showing
no obvious misalignment of tps or anything like that.
no air leaks near intake (checked negative with propane for rising idle)
not a totally failed main coil - disconnecting either main coil makes it idle rough - this idles OK
added some enzyme fuel treatment much touted here in the methanol-rich california scene.
figured maybe bad gas
ran almost empty, added four gallons (american ones, not imperial ones) to tank and another dose of fuel treatment
still runs rough with throttle whacked open - almost like starvation... if you hit throttle hard it stumbles... if you back of a little bit it runs smooth, rpms keep climbing - can get it up to speed just fine as long as dont try too much throttle at once
might be getting better but not sure

good enough to commute but not fun
can pull tank next time it is low and drain looking for water but ....

So: theories include

1. a bad coil - fine if not under load but failing if under load?
rain or dry seems to make no difference... also cold or hot makes no difference - in old days coils usually more likely to fail when hot/wet?
This is a dual plugged bike

2. clogged injector - maybe a dose of injector cleaner with next tank?
would a dirty injector be fine under short fuel delivery bursts but not under larger ones?

3. dirty fuel pump sock or failing fuel pump starving rail at high load?
codes didnt show a fuel pump fault - bike tipped to right, pump would have gone high not bathed in flakes of crap?

At some point will pop rockers, check valve clearances etc all electrical connections but doubtful any of those things changed so rapidly as to be good/not good so quickly

Fast stop/tipover maybe has nothing to do with this - still suspect bad fuel but inexperienced - since I have been on injected bikes (mid nineties and maybe eighty thousand or a hundred thousand miles) have not had this sort of problem.

I know some K bikes with "coil at plug" had coil issues with ageing plugs but dont think boxers suffered from this.
tip-over was slow enough I don't think right side main coil actually took any sort of physical shock


What say ye, gentlemen and ladies of experience?

Mark in sunny kalifornia except when it is pissing down like this week

 

[trainman]

removing the plugs will show if you have a cylinder issue (ie coil or injector) by the colour of the plug, maybe the shock broke a plug or coil (coil swaps can be done too), worst case ride a bit with each plug cap pulled, if one makes no diff then thats your waffy coil/plug

the exhaust lambda sensors are exposed, did the RH one take a biff??

i take it the throttle linkages twixt one side and the other didnt pop off, its happened to many and means the two sides arent synced

 

[Bendy toy]

or a foot hit the LHS throttle body potentiometer?

 

[Fanum]

It ran ok after impact, and on the way home.

Therefore its unlikely to be anything knocked out of place (EG TPS) or it would have shown up immediately.

I reckon shit in fuel supply system somewhere.

 

[Bendy toy]

It ran ok after impact, and on the way home.

Therefore its unlikely to be anything knocked out of place (EG TPS) or it would have shown up immediately.

I reckon shit in fuel supply system somewhere.

Could be a coil was cracked and broke down later. Also check all the other exposed fuel and ignition stuff on both sides.

 

[vfxmark]

removing the plugs will show if you have a cylinder issue (ie coil or injector) by the colour of the plug, maybe the shock broke a plug or coil (coil swaps can be done too), worst case ride a bit with each plug cap pulled, if one makes no diff then thats your waffy coil/plug

the exhaust lambda sensors are exposed, did the RH one take a biff??

i take it the throttle linkages twixt one side and the other didnt pop off, its happened to many and means the two sides arent synced

will look at plugs tomorrow - now that I have run enough like this to maybe see something.- suspect that they will not show much difference since at less than 2/3 throttle it runs fine (though it idles smoothly but sounds a bit different from usual)
if had spare coil would swap it in and out both sides to see if prob goes away but dont have a spare - not inexpensive either.
With either main coil disconnectedit runs much much worse so if a bad coil probably a marginal bad not totally non-functional..
I think if you fire these coils without a plug on them you can burn the coil, so I would be disconnecting the coil from the can bus harness and leaving it on the plug methinks.

 

[vfxmark]

removing the plugs will show if you have a cylinder issue (ie coil or injector) by the colour of the plug, maybe the shock broke a plug or coil (coil swaps can be done too), worst case ride a bit with each plug cap pulled, if one makes no diff then thats your waffy coil/plug

the exhaust lambda sensors are exposed, did the RH one take a biff??

i take it the throttle linkages twixt one side and the other didnt pop off, its happened to many and means the two sides arent synced

I think sensors are OK - if the loop were open it would have shown a code on the computer I think...

I did check all connections to tps, injectors, etc...
if anything took a hit it would have been tps on left side but it looks un-disturbed

FYI also checked to make sure cables had not jumped their bell cranks or picked up debris - butterflies seem to be in sync - mercury carb sticks show nothing out of the ordinary at idle or at half throttle (half throttle much touchier than full throttle where you are looking at more or less smooth bore)

 

[vfxmark]

Could be a coil was cracked and broke down later. Also check all the other exposed fuel and ignition stuff on both sides.

was one thought...wish i had a spare coil to swap in and out...might just bite the bullet and buy one..... might swap main coils right for left and see if it sounds/feels any different at all but that is sorta subjective - cant really test it on the centerstand - must be under load to feel difference

thanks everyone - keep thinking - I will report if/when I get to the bottom of it

unfortunately real life is intruding on the process.

will try a bottle of injector cleaner in next fuel tank if nothing else figured out...

 

[ebbo]

Unwilling to rev, nothing on diagnostic, I'd be looking at the coil sticks first

 

[kwallace21]

Don't use injector cleaner. Clogs everything up if it's left lying.

 

[vfxmark]

Don't use injector cleaner. Clogs everything up if it's left lying.

good tip
was thinking of maybe adding a few ounces of toluene - found in fuel already, might disolve gunk on injector tips if they are dirty, but I think other steps first - if I drain tank and fill it with clean then if prob still there go after spark next
at 35k miles it is almost ready for plugs... might replace all the plugs if any look dodgy... apparently tired plugs have been implicated in premature coil failure with some k bikes

 

[duckspeed]

It ran ok after impact, and on the way home.

Therefore its unlikely to be anything knocked out of place (EG TPS) or it would have shown up immediately.

I reckon shit in fuel supply system somewhere.

I am going with Fanum on this one, don't go chasing shadows and guessing.
Think it through !!

 

[Greenman14]

Symptoms are similar to my KTM when the fuel pump was failing. And it does sound like a fuel problem to me.

 

[vfxmark]

urrrgggghhhh finally got it on the lift at home

right side main coil had cracked near the plug-end rubber bootie that fits over the spark plug...signs of arcing.
maybe running on second plug mostly but plug color looked good so I am guessing it was mostly working but arcing to the cylinder head sometimes.


end of that mystery didnt fall far enough over to actually impact the plastic cover or anything - suspect shock and old age - potent combination


thanks all for your thoughts!

 

[skywalker]

Change the spark plug. Its not uncommon for the porcelain part of the spark plug to fracture internally causing your symptoms. If its broke the coil it'll have fractured the spark plug

 

[vfxmark]

good thought
i'm 800 miles from the 36000mile service, might just change all the plugs at the same time and be done with that

 

[vfxmark]

update
Changed all four plugs, replaced the broken coil, replaced the missing fork reflector that had popped off in the mishap.

While I was at it, I changed brake fluid in upper and lower circuits (06 servo ABS) without benefit of fancy funnel

Brakes work fine

Engine runs cleanly and accelerates flawlessly - obviously the left side fork reflector is critical to proper engine tune.

Happy Christmas and New Year, since we'veobviously escaped the doom the Mayan's implied by not bothering to run their calendar any further forward.
mark