New to me GS500 stumbling and dying

[FollowingGhos...]

Hi all,

Just got myself a GS500 cheaply with 7500 miles on it, so it's barely moved since 2002 when it was first registered

However, it's been sat for a few years, then serviced, then sat again and I think it's suffering for it.

I was going along the motorway when suddenly I started losing power and it was chugging and slowing down. I pulled onto the hard shoulder with the clutch in and it just died.

It started up after a few goes cranking, then started stumbling and died about a mile later

I've taken it out for a run after draining the carbs and it seems better. There wasn't much/any gunge that came out of the carbs. For obvious reasons, I didn't fancy taking it on the motorway again, especially in the dark, but it was happy in 6th at 50

Does anyone know what else I should check?
Both plugs look pretty much bang on normal (as per the picture guides etc), oil is reasonably fresh.
It is booked in for a full service on Friday, just to get it checked over as much as anything else, but I want to ride it in the meantime.

[Kawasaki Jimbo]

Sounds like carb icing. Try a bit of Silkolene Pro-FST in the tank.

[FollowingGhos...]

[Kawasaki Jimbo]

Yes to all that. I can't promise it's carb icing but it sounds classic. Given a few minutes to thaw it might not happen again, or it could return within a couple of miles. You'll only get it with a particular band on the temperature vs humidity chart. It can be colder or wetter and it won't happen, so it's hard to predict. I wasn't out today but I can well imagine that the conditions were right. I wouldn't spend a lot of money on workshop hours trying to solve a mechanical problem unless it does this a lot, which might suggest you have another problem.

[P.]

Set the tank to PRI as well. Remember to turn it off when stopped. Basically check the fuel tap as its a common failure point.

Once that is fixed, chuck it up for sale and buy anything else.

[Rogerborg]

I'd also go with fuel starvation under load, so fuel tap, sticky floats, tank breather.

What Paddy said, or strip and clean the carbs, then what Paddy said.
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Having sat for a few years, it screams of blocked carb jets/passageways. Before you go to the effort though, double check fuel is freely flowing from the tank and it;s not just a blocked breather or tank filter. Pull off the hoses and let a pint or so flow into a jug.

I've just recommissioned an NSR125 after a few years. The carb when dismantled had blockages and green gunk all over the shop.
It spent a good half hour in bits, in a little Ultrasonic cleaner all even then the pilot jet was still blocked. The tiny filter on the fuel intake wasn't too healthy either. After this, it started on the button.

Modern fuel when it evaporates, leaves some rather nasty residues, a bit like a green varnish.
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[chris-red]

As Paddy said Fuel Tap to prime see if it still does it. The Fuel taps on them ALWAYS go wrong.
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