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Main Area => General GS500 Discussion => Topic started by: Kiwingenuity on July 24, 2017, 11:58:33 AM

Title: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 11:58:33 AM
So I have had a weird issue pop up recently - thought I had traced it back to a possible HT lead issue when the bike got a bike wet in heavy rain.  This morning it decided to have anther go..

Cold start, ride bike for about 25km (15mi) - pretty much 100kph (60ish mph) the whole way along a fairly flat expressway to work.  No stops, just cruising along.  Get to the stage of slowing down for the exit and the bike starts to bog down a bit - could smell some fuel at this stage.  Keep slowing down and realise that the bike is going to stall / apply a bit of throttle and keep it in gear (thankfully the light was green and its all downhill to our office).

If you slip it into neutral and throttle off, the bike will stall / engine will die. If you keep it in gear the engine turning over seems to keep trying to just run. Once I pulled into the parking area at work I let it idle out in neutral, and it will not start again at the moment (assuming its flooded).

EDIT: It started again with choke (still warm) - and it you open the throttle just a bit you can keep it running.  It won't idle still.

Pretty sure fuel is on PRI. new plugs, clean coils, new fuel line just at the weekend - but zero issues yesterday.

Any ideas before I pull her apart again? I am thinking stuck needle valve? but if there are any quick things I can try first that would be great to know.
Title: Re: Engine Stall after high revs
Post by: mr72 on July 24, 2017, 12:14:28 PM
compression test, valve clearance check... hopefully it's carbs. for a good starting point, chase down whatever the last work you did on it was and double check all of that.
Title: Re: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 01:16:36 PM
Its probably due for a valve clearance check - just picked up a second hand carb from Oz so hopefully that will make its way over the ditch by the weekend...

May have to dust off the NBC110 green monster (Super Cub) for a bit of a workout the rest of the week :icon_mrgreen:
Title: Re: Engine Stall after high revs
Post by: qcbaker on July 24, 2017, 01:19:10 PM
If you're running on PRI and smelling fuel, its a good chance your carbs are overflowing due to a too high float level or stuck float needle. Make sure float level is set correctly and that the needle is not stuck. Then, set the frame petcock to ON instead and see if the problem persists.
Title: Re: Engine Stall after high revs
Post by: SterlingCycles on July 24, 2017, 01:46:20 PM
Quote from: qcbaker on July 24, 2017, 01:19:10 PM
If you're running on PRI and smelling fuel, its a good chance your carbs are overflowing due to a too high float level or stuck float needle. Make sure float level is set correctly and that the needle is not stuck. Then, set the frame petcock to ON instead and see if the problem persists.

I second this. I never use Pri. I'm on ON or RES if I'm low on gas.
Title: Re: Engine Stall after high revs
Post by: qcbaker on July 24, 2017, 01:59:44 PM
Quote from: SterlingCycles on July 24, 2017, 01:46:20 PM
I second this. I never use Pri. I'm on ON or RES if I'm low on gas.

I only ever use PRI if the bike has been sitting (like after being winterized) and the carb bowls are empty.

Title: Re: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 02:01:49 PM
Thanks all, looks like a stuck float needle - one of the other guys just came up and reported a puddle of fuel under my bike..
Title: Re: Engine Stall after high revs
Post by: 89500inPA on July 24, 2017, 02:39:08 PM
If you left it parked in PRI, and there is a puddle of gas under your bike, you might be hydrolocked. DON'T try starting your bike until you are sure your cylinders are clear of fuel!
Title: Re: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 03:17:40 PM
Thanks for the caution - I will pull the plugs at lunch and let it all dry out..
Title: Re: Engine Stall after high revs
Post by: SterlingCycles on July 24, 2017, 03:28:00 PM
(https://i.imgur.com/u5dabXi.jpg)

Fixed*
Title: Re: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 05:32:37 PM
Thats a HUUUUUGE image.. point taken it shall remain "On" - and yep, left cylinder was full of fuel.
Title: Re: Engine Stall after high revs
Post by: SterlingCycles on July 24, 2017, 05:40:29 PM
Yeah....sorry about that...trying to get the hang of posting here. But figured I'd post that. Came right from the manual.
Title: Re: Engine Stall after high revs
Post by: ShowBizWolf on July 24, 2017, 05:48:02 PM
Quote from: 89500inPA on July 24, 2017, 02:39:08 PM
If you left it parked in PRI, and there is a puddle of gas under your bike, you might be hydrolocked. DON'T try starting your bike until you are sure your cylinders are clear of fuel!

I'm gonna check this too. Two weeks ago I left my bike overnight with the valve halfway between prime and reserve. Didn't realize I turned it too far. :technical: Saw some drips under the bike the next day... checked the oil level and it was higher than I keep it. Oil change time :icon_rolleyes: ...and filter too of course and might as well finally replace the leaky pan gasket while I'm at it.

edit: A thread I found helpful: http://gstwins.com/gsboard/index.php?topic=65824.0
Title: Re: Engine Stall after high revs
Post by: Kiwingenuity on July 24, 2017, 08:36:19 PM
So my bike started again once all the fuel was removed from the LHS cylinder - no more drips - but it did take a bit of time to get back up to some degree of a "normal" Idle. Ran the 25km home at a sedate mix of 50-90km/h but still seems a little sluggish.

Got some seals on order and a re-furb carb - looks like my weekend should be productive..

Alright, time to indulge in the power of a 110cc single, binary throttle, 3 gears and no clutch..  :thumb:
Title: Re: Engine Stall after high revs
Post by: Peter Tez on August 07, 2017, 09:07:07 AM
so how do you remove the fuel from the cylinder?
Title: Re: Engine Stall after high revs
Post by: J_Walker on August 07, 2017, 12:59:16 PM
Quote from: Peter Tez on August 07, 2017, 09:07:07 AM
so how do you remove the fuel from the cylinder?

pull the sparkplugs, Turn the engine so the cylinder is at the highest point, if you can see a puddle of fuel, stuff a tampon [get the "Low flow" ones] in there to soak it up. no fuel, move to the next cylinder. once done, depending how long its been flooded in there [more then say, 2 hours] change the oil. and you're all good.
Title: Re: Engine Stall after high revs
Post by: ShowBizWolf on August 07, 2017, 02:33:46 PM
Hahaha that's awesome!!! Another use for "ladies' days" equipment :icon_lol: :laugh: :icon_mrgreen:
Title: Re: Engine Stall after high revs
Post by: Peter Tez on August 07, 2017, 03:53:32 PM
thanks! good to know...
Title: Re: Engine Stall after high revs
Post by: 1018cc on August 08, 2017, 12:14:28 PM
If you don't care about the mess / potential fire danger take out the plugs and hit the starter for a second. The fuel will come rocketing out - cover the spark plug hole with a rag.

Sent from my F8132 using Tapatalk

Title: Re: Engine Stall after high revs
Post by: qcbaker on August 08, 2017, 12:25:38 PM
Quote from: 1018cc on August 08, 2017, 12:14:28 PM
If you don't care about the mess / potential fire danger take out the plugs and hit the starter for a second. The fuel will come rocketing out - cover the spark plug hole with a rag.

This strikes me as a great way to set your bike/self on fire. Much easier to use the tampon method.

If you MUST do this for some reason, disconnect the spark plugs entirely first to minimize fire danger.
Title: Re: Engine Stall after high revs
Post by: mr72 on August 08, 2017, 12:58:48 PM
Quote from: qcbaker on August 08, 2017, 12:25:38 PM
This strikes me as a great way to set your bike/self on fire. Much easier to use the tampon method.

Without context, this is a pretty hilarious statement.

:)

Carry on... FWIW I subscribe to the "let the fuel evaporate" method but a tampon attached to a string would have been a pretty good idea to get that last ounce of fuel out of a tank prior to painting.
Title: Re: Engine Stall after high revs
Post by: J_Walker on August 08, 2017, 01:32:29 PM
Quote from: mr72 on August 08, 2017, 12:58:48 PM
Quote from: qcbaker on August 08, 2017, 12:25:38 PM
This strikes me as a great way to set your bike/self on fire. Much easier to use the tampon method.

Without context, this is a pretty hilarious statement.

:)

Carry on... FWIW I subscribe to the "let the fuel evaporate" method but a tampon attached to a string would have been a pretty good idea to get that last ounce of fuel out of a tank prior to painting.

My good sir, they have strings on them already.  :D

okay ill plug up and stop making tampon jokes.
Title: Re: Engine Stall after high revs
Post by: ShowBizWolf on August 08, 2017, 05:23:58 PM
He meant it'd need a lonnnnggerrrr string to reach into corners of a fuel tank lololololololol

This is hilarious!! :icon_lol: :icon_mrgreen: :laugh:
Title: Re: Engine Stall after high revs
Post by: ajensen on August 08, 2017, 07:57:04 PM
Many years ago, when I was working at Hartman's Yamaha in Tallahassee, FL, I set a 400 Enduro on fire. The crankcase was full of gas, so I pulled the plug and started pushing. I had left the ignition on, so the spark ignited the gas. I ran inside the shop only to find that the fire extinguisher was empty. Then I went up front to the parts department to get theirs. I am a calm person by nature and especially calm in emergencies, so the parts manager at first refused to believe that there was a motorcycle burning up in the parking lot. I finally convinced him to give me the fire extinguisher, and he followed me to the flaming 400. I think he was surprised to the point of panic. Unbelievably, there was almost no damage, so I just cleaned the bike up, replaced the fuel line, and kick started the engine. The owner never knew, but I learned a good lesson.