Situation:
2013 R1200RT camhead: Engine rpm’s dip too low below idle rpm upon throttle close. Happens both when just blipping the throttle while the bike is stopped in neutral and when slowing to a stop and pulling in the clutch. Engine speed was dipping to ~600rpm, then recovering to a normal idle speed of ~1,100rpm. Upon an ECM reset they’re now only dipping to ~800rpm, but still not “normal”.
Background:
A few weeks ago, while attempting to pass a slow car, when I cracked open the throttle, my RH throttle body cam broke OFF the throttle shaft (it took me a while to figure out what was going on - I checked many things before discovering the actual problem and documented it all, but did not include all of those details here as they seem irrelevant).
Assessment:
Recommendation:
THANK YOU in advance for your help!
2013 R1200RT camhead: Engine rpm’s dip too low below idle rpm upon throttle close. Happens both when just blipping the throttle while the bike is stopped in neutral and when slowing to a stop and pulling in the clutch. Engine speed was dipping to ~600rpm, then recovering to a normal idle speed of ~1,100rpm. Upon an ECM reset they’re now only dipping to ~800rpm, but still not “normal”.
Background:
A few weeks ago, while attempting to pass a slow car, when I cracked open the throttle, my RH throttle body cam broke OFF the throttle shaft (it took me a while to figure out what was going on - I checked many things before discovering the actual problem and documented it all, but did not include all of those details here as they seem irrelevant).
- Upon a GS-911 scan, NO faults were detected.
- I replaced the battery (needed one anyway and part of the many things I checked in troubleshooting).
- I checked the TPS sensor. Seems to be fine at WOT and closed values AND it sweeps smoothly when checked with an analog gauge.
- I replaced both throttle cams with ATC brand CNC aluminum throttle cams.
- I cleaned the throttle bodies upon re-assembly.
- *(The RH throttle body did fall off the bench while working. (Yikes). I inspected it and didn’t notice any dents, dings, or cracks. The idle actuator was still in place when this happened, and it seemed to still work upon re-assembling the throttle body on the bike.)
- Upon re-assembly, I left the throttle blade screws loose while actuating the throttle shaft open/closed to make sure the blade would fully close, and the throttle stop would rest against the factory-set throttle-stop screw. I did NOT touch factory set throttle-stop screw.
- Installed NEW fuel injector o-rings with a light application silicon as a lube.
- I performed the idle actuation recalibration with the GS-911.
- I performed the synchronization process. I only adjusted the RH cable adjustment nut at the throttle body in order to get the vacuum reading the same at the specified 1,400-1,800rpm. Both throttle bodies were readying dead-on at idle AND at ~1,600rpm.
- I adjusted the main throttle cable at the twist-grip to the specified 2-3mm slack.
- I attempted to also adjust the lower cable (cruise control), but not sure how this is supposed to be done exact. Cruise seems to work fine and shuts off when I roll the twist-grip forward.
- The “situation” (see above) happened with a dip to ~600rpm and sometimes would stall the engine. Engine would stop stalling once up to operating temp, but dip was still present.
- I re-set the ECM by disconnecting the battery for 30min and reconnecting. Dip still present but only drops to ~800rpm now. Still not “normal”.
Assessment:
- Not sure I can assess much further.
- One thing worth adding – Upon “spirited” power downshifting, I do notice more burble (light popping), which is indicative of a lean condition.
- Other than the undershooting rpm condition, the bike seems to run better than before the incident.
Recommendation:
- This where I could use further insight and guidance.
- *I will add: I have only put 14 miles on the bike since I did the ECM reset. Will it re-learn fuel mapping and self-correct over time?
THANK YOU in advance for your help!
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