Fuel cut out on deceleration

[JayBee]

Hi, I'm new to forums and the GSX1400 so I hope this question appears and I'm not breaking any rules! I have a 2007 Limited Edition GSX1400 that only has 7000miles on it because it is my 'back up' bike. Can't give up the VMax! Anyway the problem is this. It ticks over perfectly at the right engine speed. The fueling on launch, hard acceleration, normal running etc is absolutely faultless, best I've ever had. But on deceleration, whether upright or leaned over, it sometimes suddenly cuts out at low revs, such that maximum engine braking occurs. It cuts at about 2000rpm or less, the tick over is set to 1200rpm and is very stable. It has never cut out or faltered no matter how long I've left it ticking over and the response to sudden throttle opening is instant. It can be a bit dodgy around mid corner when pushing on, you can sometimes feel the rear tyre protest momentarily! It doesn't happen all the time and when it does opening the throttle even a tiny amount starts it running again almost immediately. It runs faultlessly apart from this. Any suggestions appreciated.

[Notty]

Welcome - Croeso  sounds like Fuelling to me but I am sure someone with more experience than me will answer your problem 

[JayBee]

Hi Notty,

Thanks for the welcome from Wales. I did just under 300miles in Wales yesterday on the GSX so as you can tell it runs well enough most of the time. Prefer carbs myself being old school.

[seth]

Hiya welcome to the org.
You should pop in to the bar and introduce yourself.
Your problem could be throttle portion sensors or even throttle cable adjustment.
Tick over should be 1100rpm
Maybe even dirty fuel filters
All are covered here so use the search box and have a look also a few other owners in your part of the world who might be able to help you.
Good luck

[Blubber]

Welcome 

Hope you find the source of this problem soon so you can enjoy the bike.

[Del]

Hi JayBee

Welcome on board mate   

Del

[KiwiCol]

Hi Jaybee, welcome aboard.   Your issue reads quite 'owww, don't like the sound of that', but I don't think it's anything too serious.

We've had a couple of other instances of owners asking about the same thing.  I don't think the fuel filters are to blame in this case, probably more likely there's too much slack in your throttle cables, as when you're decelerating and engine is around 2000rpm, (that's close to idle) if you'r cables are too slack, the throttle bodies will go to the idle position, giving max engine braking effect.
You say it responds instantly with a bit more throttle, if the engine had 'cut out' as you say, it wouldn't respond to more throttle by starting again, you can't push start these things like a carb bike.  (yes I know Andre) Are you sure the engine has actually died at these points?  as in, if you 'coasted' to the side of the road, would the engine be stopped?  Might want to try that & see if it's actually stopped, I'd be surprised.

Anyway, I'd look at cable tension & idle adjustment back to 1100rpm.  There's a few who run idle at 1200, but most stick to factory settings on this.  Maybe check chain slack too & then start on TPS checking - but that's another story.

Good luck mate, have a wee tinker & see what turns up.

[JayBee]

Hi Seth and others,

Very much appreciate your willingness to respond so quickly. Please accept my apolgies, I thought I had put something in the Introduction but as I said I've never used a forum before. It's taken a while to work out how to reply to you! Must check to see if it appears.

Anyway throttle cable adjustment is spot on, it was the first thing I checked. I could set tick over to 1100 if you think it will be any different. Haven't checked TPS voltages yet, mainly because the pick up on acceleration is so so good. Would be interested in anything relating specifically to deceleration because that's the only problem area, and only at the very bottom end of the rev range.

[Andre]

Good suggestions here.

I do think you can push start but you shouldn't (if remember correctly Grog told me - no jump start either)

[KiwiCol]

Jaybee, Is the engine actually stopped at these points?  ie, pull the clutch in & coast to the side of the road, is it running or dead?  Depending on the answer to this as to which direction the remedy lays.

[ARH]

Hi Jaybee and welcome!  I think Kiwicol is spot on here.  Had similar issues with my 14... was great accelerating but a nightmare coasting at around 2000rpm and decelerating exactly like yours.  Roundabouts were interesting to say the least!
I adjusted tickover to 1100, throttle cables with as little free play as possible (ignore the 3mm spec) checking full steering lock and TPS to spec.  Bike now runs and behaves sweet as. 
Hope you get yours sorted 

[JayBee]

Hi KiwiCol,

Many thanks. Yes I'd be surprised if it was not running because it ticks over so well. I will try that as you suggest. When I say 'cut out' that's the only way I can describe it. It's as if you are decelerating perfectly normally (which it does much of the time) and then suddenly it's as if there is no fuel or no sparks and you are slowing down on a completely dead engine. At that point, if you open the throttle, I guess only a few degrees, it chimes straight back in, but perhaps at say 2000rpm which is a bit disturbing! As replied to Seth, I checked cable adjustment and have 3mm slaxk at the twistgrip as per manual (2-4). Incidentally, I don't like any slack in the throttle so have tried it with virtually zero and a bit more during the course of checking it. No change in behaviour though.
Appreciate your suggestions though.

[Andre]

As ARH says, tight throttle cables setting and idle to 1100. Still would do TPS and especially STPS. Then check for vacuum leaks followed by throttle body synchronization.

[grog]

JayBee, has the PAIRS been disabled or is it still alive?

[gsxbarmy]

I had similar symptoms on my 2007 FE, adjusting the throttle cables solved the issue