Engine stuttering/starved when aggressively opening throttle

Having Problems with your BMW R1200RT/R1250RT? or have some Maintenance and Service questions?
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Mate021
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Joined: Fri Jul 16, 2021 11:31 am

Engine stuttering/starved when aggressively opening throttle

Post by Mate021 »

Hi Everyone,


im a recent owner of a 2006 R1200RT. Fell in love with this big bike :)


have a serious issue, would love if someone can offer an advice.


The engine would start stuttering, feels like its fuel starved, when i quickly add throttle. If i add throttle more slowly, than it works ok.
This happens in any gear.


In addition to this, max speed achievable by gradually adding throttle is around 150km/h, after that the same stuttering happens, and the engine looses power quickly.


What confuses me is that this stuttering always seems exactly the same, no change in intensity, sound etc.


I went to a mechanic (not a bwm shop) that changed the air filter, oil, performed the regular small service. He checked the computer, and there were no error codes. He checked the coils, and said one was changed, wasnt the original one. But doubted this issue is due to a failed coil.


Problem continued after the service, so the mechanic suggests we look at the fuel pump/electronics next.


Just wanted to hear another opinion


thanx!




EDIT
just remembered an important moment, when i was at the mechanic's shop, after the service he tested this issue by revving the engine hard while on the stand in neutral, and there was no stuttering than
but continued the same way after i rode away
Last edited by Mate021 on Fri Jul 16, 2021 12:11 pm, edited 1 time in total.
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David.
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Re: Engine stuttering/starved when aggressively opening throttle

Post by David. »

Mate021 wrote:I went to a mechanic. He checked the coils, and said one was changed, wasn't the original one. But doubted this issue is due to a failed coil.
How were the coils checked.

Does this thread from Adventure Rider, https://advrider.com/f/threads/05-r1200 ... n.1079753/ read like the problems you are experiencing.
Mate021
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Re: Engine stuttering/starved when aggressively opening throttle

Post by Mate021 »

Thank you very much! This example is exactly what happens to me, the same abrupt stutter, also all the spark plugs were changed with the problem persisting. Seems the coils need proper checking, as described in the forum posts.


Unfortunately i am not sure how exactly coils were checked. I saw the mechanic pull them from the engine while replacing all the spark plugs.
I am sure that he did not perform the kind od A/B testing in order to check how the engine runs when disconnecting them one by one.
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David.
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Re: Engine stuttering/starved when aggressively opening throttle

Post by David. »

Mate021 wrote:I am sure that he did not perform the kind of A/B testing in order to check how the engine runs when disconnecting them one by one.
Have seen a couple of videos & posts on other forums where, whilst the bike is running at idle, the LT lead on each coil stick is disconnected in turn.

The theory seems to be, if disconnecting the LT lead/coil doesn't make any difference to the running of the bike, that particular coil is suspect.

2004 BMW R1150GS Ignition Stick Coils, https://www.youtube.com/watch?v=hMJWr_BdNO8
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David.
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Re: Engine stuttering/starved when aggressively opening throttle

Post by David. »

An interesting way to check the spark gap, https://www.youtube.com/watch?v=W7LU7G-48BE

From the Haynes Manual, "a healthy system should produce a spark capable of jumping at least 6 mm".
Mate021
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Re: Engine stuttering/starved when aggressively opening throttle

Post by Mate021 »

just an update for those that have a similar issue. Turns out problem is due to a bad coil.


went to a new shop, and the mechanic diagnosed it in 5 minutes. They have ordered the new coil, and it should arrive next week.


i also asked the mechanic if he recommended replacing coils on both sides, he said no need to do that.
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David.
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Re: Engine stuttering/starved when aggressively opening throttle

Post by David. »

How was the bad coil diagnosed.
Mate021
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Re: Engine stuttering/starved when aggressively opening throttle

Post by Mate021 »

the mechanic pulled the coil out (still attached to the wire),added his own spark plug to the end of this coil, placed it close to the engine, and tried starting the motorcycle.
there were no sparks flying off the exposed sparkplug, so he said that coil was faulty
Last edited by Mate021 on Sun Jul 25, 2021 6:55 am, edited 1 time in total.
Mate021
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Re: Engine stuttering/starved when aggressively opening throttle

Post by Mate021 »

The new coil finally arrived, so i went to the mechanic this saturday. After replacing the coil and updating software, performing full diagnbistics, the machine runs much better now.
No stuttering, can apply throttle as needed. In addition i noticed i didnt need to warm up the motor for 3+ minutes (previously it would stall if i took off without warming it up for at least few minutes)


just for future reference, if anyone has simmilar issues.
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Re: Engine stuttering/starved when aggressively opening throttle

Post by burridge01 »

Nothing beats an update and a happy result.Well done fella👍
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Re: Engine stuttering/starved when aggressively opening throttle

Post by Kim_Y »

Thanks for sharing this information!!  Glad to hear it was a simple repair.  :)
-Kim Y.
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