Weird idle issue - 2006 GS500F

[rayshon]

Man, I wish I knew how prone this motorcycle was to problems before I bought it...I hope you find a fix

[mister]

Man, I wish I knew how prone this motorcycle was to problems before I bought it...I hope you find a fix

The GS500 is Not prone to problems. However, if a PO messes with it and doesn't know what they are doing and then messes some more, then a subsequent owners starts chasing their tail trying to fix what should have been left alone in the first place. Then the new owner can feel the bike is prone to problems.

As to your other thread... adjusting the valves is not going to be costing you money out the ass. You have two options. Follow the instructions previously posted and do it yourself - or - throw your hands in the air, bend over and take it right royally as some mechanic ass rapes you over the valve adjustment and your lack of willingness to do it yourself.

Michael

[Dr.McNinja]

Man, I wish I knew how prone this motorcycle was to problems before I bought it...I hope you find a fix

The GS500 is Not prone to problems. However, if a PO messes with it and doesn't know what they are doing and then messes some more, then a subsequent owners starts chasing their tail trying to fix what should have been left alone in the first place. Then the new owner can feel the bike is prone to problems.

As to your other thread... adjusting the valves is not going to be costing you money out the ass. You have two options. Follow the instructions previously posted and do it yourself - or - throw your hands in the air, bend over and take it right royally as some mechanic ass rapes you over the valve adjustment and your lack of willingness to do it yourself.

Michael

He's right, the Gs500 is a reliable bike. The only downside is it's air cooled, which I learned overheated a LOT faster than I had originally thought.

My problem is regardless of what my actual problem is there are so many "nickel-and-dime" problems that need permanent solutions that I'll be spending 300 bucks myself to finish it. Rebuild kits for older (< K4) models go for around 75 bucks, so I'd imagine if I could find a rebuild kit for my bike (2006 GS500F) it would cost the same x 2 (one for each carb). Then, I need to buy vacuum hosing and start replacing all of the hosing involved in the intake as a precautionary measure, and then finally replace the boots on the carb-head connection (which I can't find, I hope someone can identify them in the previous diagram I posted) which will be another $80. It's a good project, and with the Haynes manual finally arrived I can tackle it slowly probably.

The only reason I'd want to pay a dealer is if it's cheap enough to just get done there, where parts are at cost. Otherwise, I'm mainly going to take it to a dealer to have them tell me what is REALLY wrong so I can tackle that first instead of taking the trial-and-error approach and replacing everything.


My case is exactly like you said. The POS PO (har) didn't take care of the bike at all. It ran fine when he brought it for a test ride, started up cold great, didn't leak, everything checked out you're supposed to check out on the bike before you buy it, and then BAM this all happens.




EDIT:


Bike ran fine tonight. It was weird. Throttle is a little out of adjustment. Stalled it a few times until I realized it.  Idled solid, sounded solid, no popping, even the choke at full was choking at where it normally should be. This is by no means a fix, but I'm thinking the B12 is starting to work. Could the popping have been because of the B12 cleaning out the varnish and the varnish made the mix temporarily rich?

[twinrat]

If your vacuum hoses are in such a bad state ,check to see that rubber cap on left carburettor vacuum line is still there with its wire clip,as this blanks this port off as its not generally used.

[GSnoober]

The B12 didn't make the fuel rich or lean; it is basically a concentrated fuel detergent additive. Some / most carb / fuel injector cleaners also tend to raise the octane rating a bit; put in a lot of it and you'll smell it coming out of the exhaust when the engine is running. Put in too much of it and the engine won't even fire...

My best guess is that the detergent is soaking some of the crud off the carb guts; it only works when it is given time to soak the components. There are those who add carb cleaner and immediately ride the bike until the tank is empty, then complain when the carb cleaner has little or no effect. I don't understand that logic; if you consume the carb cleaner by running the engine, how can it clean anything?

Odds are that you're on the right track here; cleaner carbs will help you narrow down the other problems to help identify the culprits. Don't use too much carb cleaner in the gas, or you'll find yourself draining the tank; as I mentioned previously, too much carb cleaner will make the engine difficult or even impossible to start, so a few ounces per tankful is the way to go. The most you can probably use is one or two ounces per gallon of gas; after you exceed that amount, you risk making the fuel non-combustible. Use it sparingly at first and pay close attention to any changes; as you gain experience using it, you'll have a better idea of how much is too much. Personally, if I can smell it in the exhaust, I know I've overdone it, so I add gas to dilute the cleaner.

I advise people to add it to the tank, run the engine for a few minutes to get some of the detergent into the carbs, then shut the engine off and let it sit for 24 to 48 hours. Doing that will allow the cleaner time to remove some of the crud from the guts; then run the engine, and if possible, take a short shakedown ride to see what effect the carb cleaner has had. After the ride, let the bike sit another 24 to 48 hours, then test it again. When the gas gets low, refill the tank and add three more ounces of carb cleaner; then give it time to soak the carbs again.

This isn't rocket surgery, or brain science; you seem to be making progress, which is encouraging. As you've seen first hand, fuel-additive carb cleaner can really help to improve runability. Carb DIP is a different animal; it eats plastic and rubber parts and can even remove paint. The fuel additive type is much safer to use, and as you've seen, the results can be impressive.

One last thing you should consider; air-cooled engines DO tend to run hotter than those which use liquid cooling, which is why proper rejetting is so critical to an air-cooled engine. The extra fuel provided by proper rejetting keeps combustion temps lower than an engine which is running in stock / lean condition, as delivered from the factory. Emissions requirements determine the jetting as-delivered; it is up to the owner to make the needed changes to prolong engine life.

Yes, I KNOW that many people ride motorcycles that have never been rejetted; I'm not one of them. All things considered, the GS engine is incredibly tolerant of being run lean, which is a tribute to the original designers. However, once the limits of the engine design are reached, bad things happen rather quickly, which is why so many people are forced to rebuild or replace their engines. Of course, some owners decide not to replace or rebuild their engine, so the remaining usable parts end up being sold to someone else, which makes the parts-whores happy. I'm not knocking the parts-whores; if I had the money, I'd be the worst one in the universe... which I suppose makes me a parts-whore wanna-be...

Keep punching; I think you're doing fine, and I suspect you'll be back with more good news for us as you correct the problems you encounter.

EDITED to correct typos and brain-misfires

[omio]

I have had this same problem since day one of this bike 3 years ago, was told in other threads it was normal.  I have rebuilt the carbs, jetted it, still I have the hanging RPM's when I come to a stop after being warmed up and running for a few miles.  I have learned to just feather the Clutch a little and let the RPM"s go back to normal or I gear down completely as I come to a stop.  I have found it is worse when you come to a quick stop as apposed to fully gearing down to a stop.  I finally stopped worrying about it and enjoyed the ride.

[Dr.McNinja]

Once this whole mess is completely solved I plan on installing a Yoshi TRS slip-on and a K&N Air Filter on the bike to give me a reason to get back under it and swap out the jets. The wiki has jetting information for performance parts, so I'll probably end up going off that. Hopefully the bike won't run that lean after. Right now it's not a big deal, but that makes sense why the GS overheats quicker.

Next on the list though is changing out the oil and spark plugs even before the above. The spark plugs are probably worn a bit from sitting for so long and the oil is definitely old. It's at the first break-in milestone anyway. I'll install some Iridium plugs and nice oil and be well on my way to a better running engine after all this is done.


Anyway, once I get off class/work I'm going to take it out for a longer ride (~1-1.5 hrs.) and put it through it's paces. I'll update you guys on my findings then.



EDIT:


Today's trip was about 10 miles and 25 minutes longer than yesterday's. It acted a bit weird when it started. I started it with choke and it choked at about 2k, let it sit and then blipped the throttle and the choke shot up to 3k, let it sit and blipped it one more time and it was normal. Is this how it can be? It seemed to be real cold blooded today. Engine popped a few times, I'm thinking every so often it misfires and doesn't burn all the fuel which leads to the pop.

As the ride went on the bike handled better and better. Throttle response was fine after warming it up for about 10 minutes, and then riding with the choke on at about 1/2 for about a mile, and then bringing it down to a 1/4, before turning it all the way off about 10 minutes into the actual ride itself. The bike idled at stop lights just fine (Sat around 1,300) , very little popping (only heard one pop the entire ride) and everything sounded good. No knocks or pings and the engine at idle fully warmed up was running what sounded to be nominally.

About 40 minutes into the ride I started blipping the throttle at stop lights to try to get the idle to hang. Nothing. Blipped the throttle hard (revved it to 6k) and then watched it drop all the way back down to idle quickly with no real stopping. The only remarkable event was that the idle hang a little bit during one rev "cycle" at the light while I was waiting. But I was unable to reproduce it so I dismissed it as an anomaly.


The throttle decel cable is definitely in need of adjustment. Even the throttle snaps shut (implying no kinks or problems in the cable itself) it was very easy for me to accidentally be barely on the throttle enough to rev the engine. Got it home, shut it down, restarted it in the garage and blipped the throttle a few times to check again for the hang. GONE! A few more days and I'll dismiss the hanging idle as a solved, probably caused by a clogged idle circuit or something.



What it sounds like is the next pursuit is to check my spark plugs and change my oil. Oil is old and probably full of metallic stuff from the breaking in I've been doing. Plus it's about time for it's "dealer-grade" break-in service (it's got 807 mi. on the odo now). This weekend I'm going to investigate the spark plugs looking for warping. Since the bike was sitting for so long it's possible the spark plugs are bad, which could be causing the misfires when it's cold. It is almost certain the oil is really old. The battery may be going sour too, so I'll probably replace that in the next couple weeks as well around the same time I replace the spark plugs.


Once again, I'll check back in when I ride it again, and then again when I check the spark plugs. Even if they're good I'll probably be replacing them with NGK iridium's for safety sake.

[Dr.McNinja]

Bumping:


This week I changed the oil (Motul 5100), put in a K&N KN-133 oil filter, and swapped out the spark plugs with the NGK regulars. Bike fired up and ran like a beast. I was so happy. Spark plugs indicated normal wear. Not running to lean or too rich.


Drove the bike to work today, noticed the idle acting wonky. On the way home getting off the highway the idle stuck at around 3.5K-4K and would do exactly like it used to. The day was rather hot and the bike almost overheated due to it. Interestingly enough at one point I could use the clutch to bring the RPMs down using some engine retardation, but if I fully depressed the clutch the RPMs would reclimb to 4k (about where it chokes at full). The bike wouldn't "drive itself" however, and would -eventually- slow down with the engine loaded. I tried replicating the clutch causing the RPMs to rise steadily to 4k and could get it once or twice, and then it stopped doing it.


Anyone have any ideas? Any solutions on what could be done? As it stands over the winter I want to rejet my bike and throw a Jardine full system and a K&N lunchbox in there. Could this be a source of improvement? I'm 99.9% sure it's not a vacuum leak. As my previous posts say, I have already tested for it and found nothing conclusive and I find it hard to believe the vacuum leak would be intermittent.

[lamahug]

My 2004 GS500F runs perfect except for a similar stupid intermittent high idle issue.  I've put on 2800 miles this summer, and the GS500F runs perfect - plenty of power, good throttle response, no hesitation, no backfiring, etc...EXCEPT FOR THIS INTERMITTENT HANGING IDLE!

I believe that the carbs are OK, because the bike runs perfect.  What about something that is causing the throttle mechanism from returning to the idle position, be it the throttle cables, or a broken spring, or there is hysteresis/friction in the throttle mechanism or some pin is sheared on the throttle plate shaft or the throttle plates are loose?  So, there is a spring system that is responsible for putting the throttle back in the idle position - just let go of the throttle and it goes to idle.   Is it returning to the correct throttle/idle position?  How do you check that?  I was looking for a way to check this - some shaft that one could mark and observe without tearing apart the bike.  I couldn't see anything move when I moved the throttle cables.

When the high idle occurs (about 3500rpm) and I've stopped, I try to blip the throttle to get it to go back to idle.  No luck at all.  I rev it up pretty high (6K) and then just let go of the throttle, trying to 'snap' it back to idle - nope, that doesn't work either.   The traffic light turns green and off I go, and at the next stop the bike idles fine (1100rpm).   

This upcoming winter, I will try and take the throttle system apart - I'll squirt WD40 in the throttle cables/carb shafts, and then see if one can measure the throttle plate positions.  The bike needs new tires, it's oil changed, and possibly some new brake pads, so why not look at the throttle mechanism (it has 9000 miles on it)?









     

[BaltimoreGS]

Anyone have any ideas? Any solutions on what could be done? As it stands over the winter I want to rejet my bike and throw a Jardine full system and a K&N lunchbox in there. Could this be a source of improvement? I'm 99.9% sure it's not a vacuum leak. As my previous posts say, I have already tested for it and found nothing conclusive and I find it hard to believe the vacuum leak would be intermittent.

Did you drill the brass caps and adjust the mixture screws yet?  That adjustment being off can lead to the exact symptoms you are describing.  It would be better to get your problems sorted out before you start modifying the bike (though a re-jet is generally necessary on a stock bike). 

-Jessie

[Dr.McNinja]

Anyone have any ideas? Any solutions on what could be done? As it stands over the winter I want to rejet my bike and throw a Jardine full system and a K&N lunchbox in there. Could this be a source of improvement? I'm 99.9% sure it's not a vacuum leak. As my previous posts say, I have already tested for it and found nothing conclusive and I find it hard to believe the vacuum leak would be intermittent.

Did you drill the brass caps and adjust the mixture screws yet?  That adjustment being off can lead to the exact symptoms you are describing.  It would be better to get your problems sorted out before you start modifying the bike (though a re-jet is generally necessary on a stock bike). 

-Jessie

It's not. I fixed it by adjusting the idle when it was hanging at 4k. Phantom hanging idle is gone.