Training Wheel Hero
Join Date: Dec 2007
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I've got the same thing right now on my 05 - thing seems to want to drive its own, speeding up and slowing down even though I don't think my hand moved on the throttle. Drives great at times, and then seems like its got half-power.
I replaced the whole throttlebody/airbox assembly, and the only reasons left I'm guessing here is:
slight vacuum leak (from injector o-ring seats, or from 5-way split down to TB)
dirty/clogged gas route (injectors, fuel filter, possible fuel pump is bad due to sounding funny on rare occasion during priming.)
MAF sensor or wiring harness (unlikely both my MAF sensors are bad, first one tested out fine according to honda service manual) I say wiring harness because it seems like whenever I go over a bump in the road, the engine knock sensor is getting tripped and advancing the timing, as it bucks about 2-3 times a half second after the bump.
Loose engine mount bolts letting engine shake around, tripping knock sensor. (One guy posts a video about it, sounds like a variable-speed circular saw that gets louder as the RPMs rise, but not to be confused with a bad CamChainTensioner and the noise that makes)
TB Starter (choke) valves are gummed up and getting stuck at incorrect and unsynchronized places when engine idle wax unit pulls them out as the engine heats up during riding.
Rear sprocket was not mounted dead-center to wheel hub using 4 feeler gauges as shims, so while the sprocket itself is concentric, its position is essentially moving oblong like an egg - easy to tell when you go to tighten your chain tension and find its super tight in one spot, roll it a few feet, and its back to perfect spec (also could be stretched chain in just one spot, but come on now) - and that trips the knock sensor.
Out of balance wheel, bent rim, bent forks, no/incorrect fork oil in one side, bad wheel bearings, CCT is on its way out and cam chain skipped a tooth.
That damn Ethanol fuel.
The list goes on and on....
One thing I did find, however, was if I set the idle rich, it seems to go away for the most part, but its like the bike is sluggish and doesn't have that 'pick-up' like it should. My suggestion, before you go and drop $$$ trying to chase this thing, is go fill up with 93oct (no fuel inj cleaner), ride it around for about an hour, and after a good 45mph cruise come to a stop in neutral and adjust your idle thumb screw so its dead center (or just a hair higher) between the 1 and the 1.5 tick on your tach. Then go home and disconnect the battery and turn the key back to ON and leave it overnight.
Also, don't rely on engine braking as much as the ECU seems to remember what gear and at what RPM it bucks at, leading to more frustration. And make sure your chain is tensioned properly, ie have a buddy check it when your sitting on the bike. Make sure you get your battery load tested at autozone/orielly's/batteriesplus. The Rectifier/Regulator is also a known common part that goes bad on 03-06's, along with the fuel pump and CCT.
I'll let you know exactly what it is when I figure it out, but funds are tight atm so who knows just when that's going to be....
Oh forgot to mention - your clutch is adjusted right and not worn out, right? If you rev it in 2nd up to ~8k RPM and drop the throttle, the RPM needle doesn't bounce around when you cut the throttle, does it?
2005 CBR600RR - bone stock
Last edited by Amp4027; 03-20-2017 at 06:22 PM.