Stuttering/cutting out.....again....

Sooooo after changing the in tank fuel filter I though my stuttering/cutting no out at speed was cured, a "spirited" run today showed it has come back.
Hard acceleration between two corners, 4th gear at about 6500rpm it cut out/lost power, no lights on dash, near zero revs, just like hitting no a brick wall, blip throttle and it picked up again. 62k on the clock, 2008 model

Coil sticks ?

Keep her below 6k and all feels normal, would a coil breaking down do it at random or lower revs?

Does this happen more when the bike is warm? I guess the spirited riding thing suggests so. A call stick can breakdown when warm but function well when cold, which is why I ask.

Not sure..... I'll thrash it to work tomorrow morning and report back����

Sounds like a lack of fuel flow to me

I would have thought problems deeper in the fuelling system/ECU/exhaust would have thrown a warning light & would therefore leave their code on the ECU. Might be worth getting a scan. Can you detect whether you are losing both cylinders, or just one - not easy I know. My neigbour sorted out an issue with his bike, by carrying a lazer thermometer with him. When the bike started playing up, he pulled up promptly, killed the engine & took temperature reading off both headers. It identified the cylinder playing up, & the problem was found to be a tight exhaust valve.

However, my money is on the coil sticks breaking down too. Maybe water ingress down the plug socket. Commonplace in my K16 days - starts off barely noticeable, just the odd stumble, then gets worse progressively. Doesn't always throw up a code in the early stages. Not so bad when you've got 6 cylinders to play with though.

However searching the parts bin of random thoughts: -

Side Stand switch - suffered it with a Kawasaki twin. At certain revs, when engine vibes peaked briefly, the side stand cut out would intervene all on it's own. Disconnected the system, including the clutch interlock as a quick fix & ordered up a new switch once proven, as the original was corroded beyond repair. Also checked out & replaced the local wiring/connectors.

Fuel cap/tank breather - again on another Kwack. the fuel tank breather was blocked & the bike would cut out randomly after about 10 miles. Seems a bit unlikely with our pumped system.

Injectors - usually pretty reliable these days, but endure harsh conditions. Crap fuel/water & diesel contamination could impact. Seafoam? My old Hayabusa picked up copper contamination from the fuel pump, which caused injector problems - didn't throw a code initially, when just the odd stumble, but did cause a panic when it worsened during a tour around Spain/Portugal.

Plugs & electrical connectors - a mate of mine didn't seat down the coil stick firmy, so it was bouncing around on the plug top, causing a misfire induced by engine vibes. Turned out he had damaged the coil stick, when removing it for a plug change. Expensive mistake.

Alarm - I have known these play all sorts of tricks, particularly retrofit. Usually crap wiring, or cables pinched. Zapper can play up too, usually from being left attached to the bike keys & shaken around in all weathers when riding. Keep the fob separately in your pocket.

Hope you can track it down - keep us posted.................... KEN

Thinking it's more fuel related to be honest, low fuel light today and it cut out 10yds from setting off..... Ran a bit "off" as in very choppy on closing the throttle, refuelled and then it stopped again after about 10yds, I'll order a pump and see what that does

Serious3 said:

Thinking it's more fuel related to be honest, low fuel light today and it cut out 10yds from setting off..... Ran a bit "off" as in very choppy on closing the throttle, refuelled and then it stopped again after about 10yds, I'll order a pump and see what that does

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Must be annoying this, but your solution sounds expensive without more tangible evidence IMHO. Surely the pump will show itself, both with a code on the ECU (low/intermitant fuel pressure) & by simply listening to what is happening. If you take the seat off, then turn on the ignition, the pump can be heard clearly & it's tone should change once the system is up to pressure. When failing they usually sound a bit slow/erratic.

Have you run Seafoam, or similar, through the system? Important if you have you used any E10, or above, fuel, or suspect diesel/water contamination.

Have you had the TO & TP Sensors checked out? Tip Over should close when the bike is leant over beyond c45 degrees from vertical, so can be checked easily with a meter. For instance, on my mates Suzuki, his TOS was hanging loose somehow(probably his spannering) & was cutting the motor randomly. The Throttle Position Sensor can also be checked with a meter, first for input voltage, then for earth leakage, then for resistance values between closed/fully open (sorry, I don't know these for our system, so you would need to search) & can be reset accordingly. Then there are the CKP & CMP sensors - If these fail/think they have got out of sync strange thing can happen, but they usually throw a warning light. I have seen failing cam chain tensioners/worn slippers cause issues too but we won't go there. Then there is the Lambda sensor, which can get coated with contaminates & send fuelling haywire, but again this should throw the engine light.

Just a few more thoughts - hope this helps ................... KEN

Chatting to a mate this afternoon about your problem. He reminded me of the kill-switch issue that we see on certain other BMW bikes.

There, the weather got to the internal mechanism & was randomly killing the motor on some bikes. Guys had the motor die on lane 3 of the M/Way which was a bit scary. BMW replaced all the RHS switchgear quietly, but some riders still found the replacements failed. Not a normal problem with the twins, as far as I am aware, but might be worth checking.

...................... KEN

I'll give it a squirt with contact cleaner and wd40....

Are you sure the tank is venting properly? Next time it happens, try popping the fuel cap open/closed, and see if the problem is still there. When you open the cap, have a listen to see if there was a vacuum. I seem to recall that a few have had this before.

Have a similar problem - notice my bike runs well when the tank is fully topped up and as the level drops it starts to appear after the half way level. Thought it was a venting issue so I ran it with an open fuel cap - problem persisted. It appears to be the fuel pump problem in my case. From the research I've done - when the level drops the pump is working harder and is over heating - apparently there is a thermister that kicks in and cuts the pump when the temp get too high. If I leave the bike for a while and top up with fuel the problem goes away,

Have ordered a stock OEM pump - might help you in your quest for solutions!

Fitted a new pump yesterday, weathers to cold and frosty to ride so I'll update when I get out on her

And............. it's still doing it new pump and new in-tank filter, hot r cold full or empty doesn't matter. Coil sticks next methinks

A longshot but Worth doing a separate thread 'anyone around Galway with GS911' willing to help with getting it plugged in before you put more £££ in...

Q plate said:

A longshot but Worth doing a separate thread 'anyone around Galway with GS911' willing to help with getting it plugged in before you put more £££ in...

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Found one!

I tried coil sticks - I have a pair if you want to try them I can parcel motel them to you - if they don't do the job just send them back!

Also tried a crankshaft sensor - which I thought was the initial problem.

Same crankshaft sensor fits the 1200gs and a few other models - loads on ebay... very cheap...

Tearaway said:

I tried coil sticks - I have a pair if you want to try them I can parcel motel them to you - if they don't do the job just send them back!

Also tried a crankshaft sensor - which I thought was the initial problem.

Same crankshaft sensor fits the 1200gs and a few other models - loads on ebay... very cheap...

Click to expand...

You sir are a gentleman! I'll get it plugged in in the next few days or maybe a week and see if it's throwing errors, if not I shall take you up on your offer!

As mentioned before, check the side stand cut out switch.

Mine had similar issues, would be fine then just die and slow and then pickup again for no reason. Checked the side stand and it looked just fine so carried on for awhile with no further issue till one morning it cut out again just as I was setting off, found some gravel stuck between the side stand and switch which was just enough to flip it out, cleaned it out and never happen again.