R1200GS Stumbles/Coughs With Agressive Throttle After Being Dropped

[SuperCub]

Hello All!

I'm sorry to cross-post from Advrider.com but both my dealer and I are stumped on this one and my R12GS has been out of service for over three weeks. I've had it for 5 month and I'm dying here!


Please see the following link for the complete thread.http://www.advrider.com/forums/showthread.php?t=96677&page=1&pp=15


Thank you in advance for your attention!

I was doing some dirt riding the other day on my R12GS and dropped it in a rut at about 5mph. It went all the way over onto the right side handlebars. I turned the key off as the servos were running, waited about a 30 seconds or so and then picked it up. Unfortunately I didn't have a camera to record the event because everyone likes to see the big pig upside down...

I noticed a strange smelling smoke which I believed (and still do) were weeds on the exhaust.

I repositioned the handgaurd and the bike started no problem with no faults. I then rode out of the woods and parked the bike. As expected, fuel was draining from the vent (charcoal canister). I saw maybe a tablespoon of fuel(?) on the ground.

I inspected the bike and saw nothing remarkable but some dirt clumped into the right side valve cover protector and rode off. No big deal but when I attempted more agressive throttle the thing coughs, stumbles, studders and backfires. It runs fine using smooth, "normal" acceleration.

I had an appointment with my dealer the next day to do a GT1 run looking at the stepper motors (idle), firmware revision and for any faults. None were detected and I had already told them I thought stumble was due to the charcoal canister being saturated. They decided to order and replace the canister. I had intended to remove it anyway the next day (today).

Today, I removed the canister per R1200GS.info (http://www.r1200gs.info/howto/ccremoval.html) and the thing still pukes on acceleration. No change in symptoms!!!

Any ideas???

Thanks!

 

[Fanum]

No idea if there's a pair of these on the 1200 like there is on my Adv (if not, ignore this ) but I've had similar symptoms after identical drops through having the large rectangular plug with all the ignition wires (I think...never really thought about it) juat above the foot rest come loose......I think I caught it with a boot as I pulled meself out but it's happened twice now.

CHeck both of these are seated properly and dry/clean

 

[Fanum]

PS I presume the throttle cables are seated in the bodies properly and again, haven't got any grunge under the cable ends that would upset the balance?

 

[SuperCub]

Fanum Sir!

Thank you for your reply!

In regards to the "rectangular plug"; I haven't a clue but will go to the dealer tomorrow and check. This seems reasonable considering that a somewhat loose ignition wire can cause a similar symptom.

In regards to the throttle body cables; this area has been painfully reviewed and is less likely the culprit!

I believe that you are on track. All indications appear to be TB inbalance or an ignition inbalance. Another possiblity is, and related to TB inbalance, damage to an individual intake causing a mixture inbalance.

I will update as more is revealed!

All theories are appreciated!

Thank you again!

 

[Mouse]

It seems less likely but I'd check all the spark plugs and caps, seem to remember symptoms like this can sometimes be caused by badly seated secondary plug caps.

 

[GSmonkey]

It sounds as though it will be the secondary spark plug lead / coil that's come loose. Its happened to a few 12GS's that have gone over - mine included. Symptoms are hesitation on full throttle.

 

[SuperCub]

Thank you!

I regards to the spark plugs, the dealer did a "voltage test" to determine spark plug integrity (whatever that means).

Spark plug coils were test (rung out I believe) and are preceived to be good!

It's in the dealers hands and has been for a coulpe of weeks. A BMW "representitive" has been brought in to look it. (What ever that means).

I suspect that the global GS community likely has seen more than my dealer, though he has the BMW Motorrad Mechanic Community to bounce ideas off of. I don't doubt the dealers ability! I also don't doubt that I'm more interested in getting the thing quickly fixed than he may be.

So I research...

 

[SuperCub]

Latest Update!

The dealer found that the fuel pressure at the injectors was 4.7bar (~67lbs) and should be at 3.1 to 3.3bar (~46lbs) resulting in an over-rich condition.

Why this has an effect only at aggressive throttle opening baffles me...

He believes that this was a coincidence and not the result of dropping the bike. I doubt it's co-inky-dinky!

Fuel pressure regulator on order and I'll update then...

Thanks

 

[SuperCub]

Once again, sorry for the cross-post (from advrider.com).

It's all in the sprit riding the bike and not waiting to ride the bike...

Here is a further detail of why fuel pressure could cause this symptom...

Well that's what I learned as an American auto engineer...

The Squareheads could be doing it completely differently! Naw, I bet it is a rich fuel condition. No matter what, you do not want to be that far above specified fuel pressure.

I saw your early posts, but I never thought of high fuel pressure. I was imagining something more obvious like a restriction in the airbox. It sounds like you had checked the bike over really thoroughly for stuff like that. I was as mystified as anyone. Like others have said, fueling problems typically mess up your idle before anything else...

At least you have one obvious fault to fix. Hopefully the dealer has enough sense to disconnect the battery to reset the ECU. Then it's time to check the Gasinta and Gasoutta.

 

[SuperCub]

Problem Solved!

Thanks all for your help!

The thing screams again! Today was the coldest day I've ridden since I got my bike so it was awesome. Front wheel comes up through 3 gears.

The problem was the fuel pressure regulator located on the fuel injection distributor. The rear sub-frame must be unbolted and dropped to replace the regulator.

Also, after replacement of the regulator the thing ran rough at about 4k and that was solved by replacing the plugs. Apparently riding the thing after attempts at fixing the problem trashed the plugs. I dunno!

What an interesting problem and I know I've learned (learnt) a lot about this bike in the process.

I hope this thread helps someone else with a similar problem.

BTW, I put Fastway pegs and shortened the front turnsignals today too! Both took about 45 minutes!

Goin' Riddin'