Solved my 910s stalling problem after 3 years - MVAgusta.net
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post #1 of 22 (permalink) Old 08-11-2010, 01:12 PM Thread Starter
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Solved my 910s stalling problem after 3 years

Finally this summer I've spent the necessary time to try various combinations of tuning to try and solve the stalling problem that has plagued my 2006 910s for the last 3 years (since it was new). My bike would stall when pulling in the clutch coasting to a stop in hot weather, or when just idling at a stop light (again in hot weather). On a 90 degree day, the bike would stall 3-4 times per minute when riding in stop & go traffic. I had learned to never let go of the throttle and basically keep the throttle cracked at all times.

I had synced TBs, adjusted the TPS according to the FAQ, replaced plugs, replaced SPU, tried different gas, etc., etc. I'd done it all and nothing really fixed it. This year I started making bizarre and drastic changes to the tuning to see what made it worse. Through a bunch of trial & error adjustments, I gradually figured out that the richer I made the bike at idle the worse it got. But with the ECU trim screw fully leaned, and the air screws fully leaned, and my power commander fully leaned at idle, etc., etc., it still was stalling.

So for kicks and giggles, I decided to "lean out" the mixture at idle by purposely misadjusting the TPS sensor. Now according to the FAQ on setting the TPS, the "correct" setting is 150mV with the TBs fully closed an slightly jammed. The FAQ also says that most Brutale's come from the factory at around 90mV when closed, and so you usually have to increase it to 150mV. (For the record, mine was always at 150mV).

So I figured I'd set my TPS to be 50mV with the TBs closed, thinking that mis-adjustment would cause the ECU think that the TBs are more closed than they really are, which would make the ECU call for less fuel, and therefore make things even leaner especially at small throttle openings. Poof! Bike has been running almost perfect for over a week now. I say "almost" because every once in a great while it still hiccups, but it has never stalled since.

So against all recommendations, the correct setting for my TPS is roughly 50mV with the TBs closed and jammed. All the other Brutales on the planet apparently like it set to 150mV. Go figure...

Two '01 Suzuki SV650 race bikes; '06 Brutale 910 street
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post #2 of 22 (permalink) Old 08-11-2010, 01:43 PM
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Weird thing. But good for you to have it solved. Maybe someone else with the same problem can try it out too.
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post #3 of 22 (permalink) Old 08-11-2010, 03:32 PM
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good stuff.
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post #4 of 22 (permalink) Old 08-11-2010, 08:43 PM
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You can achieve the same thing with the Technoresearch software correct?
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post #5 of 22 (permalink) Old 08-11-2010, 09:32 PM
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how does it run with the TPS so off from the recommended?
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post #6 of 22 (permalink) Old 08-11-2010, 09:49 PM
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Well....I gather it doesn't stall anymore.!

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post #7 of 22 (permalink) Old 08-12-2010, 09:47 AM Thread Starter
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Quote:
Originally Posted by mrossk View Post
how does it run with the TPS so off from the recommended?
it runs eff'n perfect! i may even try 25mV on the TPS to see if i can get the last bit of hiccuping to go away, but i'm hesitant to touch it since it's never run this good before. Keep in mind the TPS setting has the biggest affect at the smallest throttle openings, and has progressively less impact as you open the throttle more and more. IOW, say my TPS is off by 0.5 degrees-- well, 0.5 degrees is a big difference in air flow when the TB is almost shut, but 0.5 degrees is only a small difference in airflow when the TB is significantly open.

the "hiccup" i refer to is when the mixture ignites back through the intake valves and up into the throttle bodies, causing the intake to lose vacuum and the engine would skip for a rev. the hiccuping is also the cause of the stalling (when you got a really bad hiccup or two hiccups in a row it would stall)

Two '01 Suzuki SV650 race bikes; '06 Brutale 910 street

Last edited by ridesideways; 08-12-2010 at 09:57 AM.
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post #8 of 22 (permalink) Old 08-12-2010, 05:37 PM
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Quote:
Originally Posted by ridesideways View Post
it runs eff'n perfect! i may even try 25mV on the TPS to see if i can get the last bit of hiccuping to go away, but i'm hesitant to touch it since it's never run this good before. Keep in mind the TPS setting has the biggest affect at the smallest throttle openings, and has progressively less impact as you open the throttle more and more. IOW, say my TPS is off by 0.5 degrees-- well, 0.5 degrees is a big difference in air flow when the TB is almost shut, but 0.5 degrees is only a small difference in airflow when the TB is significantly open.

the "hiccup" i refer to is when the mixture ignites back through the intake valves and up into the throttle bodies, causing the intake to lose vacuum and the engine would skip for a rev. the hiccuping is also the cause of the stalling (when you got a really bad hiccup or two hiccups in a row it would stall)
Sounds like you're compensating for a bad injector design (bad at idle fuel flow rates). Glad to hear you came-up with something that works though; good on ya! A stalling bike is an unsafe machine.
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post #9 of 22 (permalink) Old 08-12-2010, 09:04 PM
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Sounds like you're compensating for a bad injector design (bad at idle fuel flow rates). Glad to hear you came-up with something that works though; good on ya! A stalling bike is an unsafe machine.
Has anyone had their injectors cleaned for this problem?
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post #10 of 22 (permalink) Old 08-17-2010, 03:04 PM
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Thanks for the info, I might try that the next time I everything apart. Here's a thought, if most bikes come a 90mV maybe it's the correct setting versus 150mV which everyone believes it is.

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'88 Ninja 250 > '92 GSXR-600 > '01 YZF-R1 > '06 Brutale + '07 Customized VTX-1300
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