Engine Cutting Out on Deceleration

[BenNic42]

Hi everyone

I recently bought a 2007 GS500F. It runs well but there are a couple of issues. I had it serviced in anticipation of winter, the mechanic said it's running nicely but one of the rubber intake pipes which goes from the carb to the cylinder has a leak. I've bought a new one but nowhere can fit it any time soon.

My problem is this, I've noticed that when I have to slow down quite quickly and block change down the gears, the engine cuts out. This has happened twice in a few months. Is this a symptom of the leaking rubber intake pipe? I.e. is too much air being sucked into the engine and causing it to stall? When it has happened I just restart the engine and crack on with no problems.

I'm pretty new to the world of motorcycling and trying to work out mechanical issues so any advice would be greatly appreciated.

Thanks

Ben

[mr72]

Sounds to me like the idle may just be set too low.

Does it do this when the engine is cold or only when fully warmed up? How about if you turn the choke on 1/2, better or worse?

But it's a tremendous waste of time and effort to try and diagnose anything fuel-related with a known vacuum leak. You can replace that boot yourself, I am sure of it. It really is not hard at all to pull the carbs and then the boot just comes right off. But if you are going that far, I would get two new intake-to-head o-rings and replace the leaking boot and both boots' o-rings while you have it apart. Bad/leaking o-ring is probably more likely than an actual leak in the boot. Of course if it were me I'd replace both boots while it was apart. Cheap insurance.

[BenNic42]

Thanks for the advice,

It's only happened twice when I've had to slow down from speed. I was doing about 40mph, car in front slowed quickly so I slowed quickly too, then the engine cut out once I'd slowed down. Engine would have been warm at this point, I'd been riding for around 40 mins.

It normally idles at about 1500rpm but sometimes dips to 1000rpm when it's cold. Not sure how unusual that is for this bike.

And yes I did buy 2 boots and O rings. They were £30 a piece with the O ring included so thought might as well get both done.

Thanks again

[Bluesmudge]

Probably a symptom of the vacuum leak. You can't diagnose the problem until that is fixed.

Once the boot is fixed, if you are experiencing the problem still and it is not simply that the idle is set too low, I would assume tight valve clearances, especially if it goes away after the bike has warmed up.

[BenNic42]

Nice one, thank you.

I'll get it fixed soon as and post back on here.