There's been a bit of history so far with my current problem...so let me start from the beginning...


Chapter 1 :  New (to me) Bike, Becoming Roadworthy

I bought my first bike (a 2005 GS500F) used with about 16,500 miles on it.  I was going through the normal routine checks on it with the Haynes manual and checking/fixing everything I was able to (air filter, spark plugs, oil filter, etc.).  For the most part there wasn't too much to fix, the major things were a replacement front master cylinder, change the spark plugs, some worn fuel hoses (that I ripped while removing the gas tank for the first time) and some brittle plastic at the carburetor (the fuel intake T junction piece, broke as I replaced the fuel hoses...and some of the plastic possibly fell into the carburetor, not entirely sure).  The master cylinder was no problem at all, the fuel hoses were a pain in the ass but only because I didn't remove the carburetor at this point, and the broken T junction broke with enough still intact that I was able to put the fuel hose on it still.

All of this was a pain in the ass, but was ultimately a great first experience in working on my own bike.  Before buying, I had made the decision that I would do as much work on the bike as I could before going to a shop; not only to save some cash in the long run, but because I've been putting more importance on self-reliance in this area.  There's no real reason for an engine to be a "black box" that I know nothing about, and starting off by doing everything needed on a running bike seemed to be a great way to jump in.  So even though it was a pain, it was equally rewarding as my bike was finally able to get on the road enough that I was able to put about 100 miles on it...


Chapter 2 :  The Incident

Near the end of those nearly 100 miles, I was had pulled up to a red light and everything was totally fine, but I was in minor traffic and wasn't going more than about 35 or so.  I stop and prepare to turn right, the light changes to green, so I try to take off like I would normally and I find that I have essentially no power and plenty of sputtering.  I was able to get back up to about 35 or so, but that was about as much as the bike wanted to do.  Extremely convenient while I'm in a 55 mph zone...  Lucky for me, I was able to quickly find a place to pull off the highway and take a look at everything.

My initial thought was that my gas lines weren't on as well as I had thought around that broken T piece, and that had come loose or something.  I was able to easily look and see that there were no fuel leaks and everything was as dry as it should be, and the lines themselves look good.  My next thought was that possibly the T piece plastic that might have made it into the carbs actually did, and had finally caught up with me.  Either way, I was not having a good day at this point.

The only other thing to mention in this event, was that I was carrying my security chain under my seat, but I apparently hadn't secured it completely and it started to slide out while I was riding and drag behind me.  I find it highly unlikely that this is related, but I also find myself very lucky as to not have had that get wound around something around the back wheel...


Chapter 3 :  Trouble...shoot!

I was able to limp it back home without any further incident.  I stopped a few times to check a few other things, but at this point my major problems were:

• Poor acceleration
• Top speed of about 35mph
• Engine sounds "normal" and sounds like it's really trying to go faster, but it struggles to maintain 35mph (almost like a clogged air filter might act?)
• The engine was obviously missing, and vibrating/jerking more than normal when it would.
• The choke does not operate the same as it used to.  Originally, the choke acted exactly as expected, after this incident it would no longer assist in my warm-up process and throttle was required when it really wasn't before.  Originally, choke on at start, small blip of throttle, and it would take off to hold itself at ~3500 RPMs, and now it simply dies with or without choke.

Once I started in on it, I checked the obvious things based on my Haynes manual's troubleshooting section.  Here's what I did following that:

• The air filter looked good and clean.  It looked this way when I first got it, so I never replaced it.  I even blew it out with an air compressor and seemed to have nothing notable come out of it.
• I finally received my replacement T piece for my carburetor, and since I needed to get into things and take them apart anyway, I decided to fully clean the carbs and change the o-rings/gaskets/etc.  While blowing out everything, I never did notice any plastic come out...though it may be impossible to find via compressed air since it may have become a projectile...  The carburetors seem to be in good condition overall and probably didn't even need that cleaning.

After this, my problems still persisted, so I contacted mechanic friends of mine (who were unfortunately all too busy to take on new work right now) as well as a local shop.  The shop suggested that the problem might actually be my clutch, however, I remain skeptical.  My mechanic buddies don't specialize in bikes either, so I'm not sure how much more help they would be in the long run anyway.

While working on the carburetors, I also broke a hose nipple on the CA emissions charcoal canister...the feed into the carburetor.  This was another situation where I placed the hose over the remaining piece of nipple and secured it with tie-wraps since I'd have to special order that canister.  Haven't done so yet simply because the fix seems to be holding fine, and it literally had zero effect on the overall symptoms of the bike.

After putting the carb back into the bike, I adjusted the throttle cables some and had to reset the idle screw.  This improved my situation somewhat, but only enough that the engine wouldn't die as easily during warm-up and idling...the missing seemed to be reduced slightly from this too.


Chapter 4 : A New Lightbulb Clicks On

The problem sat there for a little bit until this week, when I had more time to think, research, etc...so even though I "knew" it couldn't be a problem with my spark plugs (since I personally had put them in) I decided to pull them out anyway and have a look.  It turned out, it was a good thing I did because I found new evidence, and somewhat solved some of the issue.

The spark plug on the left took very little effort to unscrew, and when I removed it it looked like a less-severe version of the Haynes manual picture for "carbon fouling" (dry, black sooty deposits).  This was especially interesting to me since I had just replaced them recently, so I decided to check the other as well.  That plug was also easier to unscrew than it probably should have been, but it was in a little better and had far less evidence of "carbon fouling".  Also interesting to me that one side was worse than the other.

While I had the plugs out, I gently used a wire brush to clean off the carbon soot built-up on each of the plugs, then I made sure follow procedure exactly from the book to put them in.  When I did this, I realized the difference from when I replaced the plugs originally...this time I had the right socket for my plugs...last time I had to "settle for" using a crescent since that's all I had that would do it.

This was some good news at least, since once I put everything back together and took it for another test ride, I had far better performance.  My slow acceleration was absolutely still an issue, but the missing was nowhere to be found and given a long enough straight path I could probably slowly climb up to 50-60mph...I was saw the speedometer get up to about 45mph before I ran out of road where I was.  This is far better than it was before...good enough that I feel I could bring it to a shop under its own power now, but still clearly not operating properly.


Chapter 5 : Where to go from here?...a.k.a. the TL;DR

I've somewhat exhausted all of my knowledge and/or tools at this point.  I'm not sure what else to try, or the things I can think of seem to be just wild shots in the dark.

I would absolutely love to fix this myself (or with skilled over-the-shoulder guidance, in the form of one of my buddies when they have time) rather than take it into the shop, just for the educational experience of it all, but I'm figuring I might need to just take it in since I also lack proper equipment.

This is the current symptom list:

• The Major Issue:  Poor acceleration -- low and high speeds; low speed acceleration and performance drastically improved over the spark-plug tightening but still not "right".  Opening the throttle completely does increase the "sound" of the engine but accelerates just about as slowly as far less throttle.
• Poor top speed, I think, because the engine seems to not be delivering the power it should...I haven't really tested the new maximum, but it's now more than 45mph when it used to be ~35mph or less.
• Neural switch, kickstand kill-switch, and headlight electrical issues have popped up...I believe these to be unrelated to the acceleration, and more related to me rerouting spark plug wires to come away from hot engine components...doing so brought it around some other electrical connectors that may simply be loose/broken.

Does anyone happen to have any ideas?  I would think air filter except that it seems pretty clean currently.  Valve clearances would be one I don't have the tools or confidence in myself to do yet, but something that seems to be possibly in need of adjustment too.

Any help would be greatly appreciated.  Thanks in advance!

This sounds a lot like a slipping clutch to me. Have you checked your clutch cable? If it is a little too tight or you routed it wrong after working on the carb, it will not release enough to allow the clutch to fully engage. This would cause these symptoms.

#5161

The first thing that comes to mind - which you didn't mention - is....

Do you have enough gas in the tank?
Is the tank petcock all the way ON? (Slot vertical).

Even if you think you do have enough gas - fill it up. Maybe the fuel lines are reversed.
Then try running in PRIME if still a problem in case the vacuum line to the petcick is on wrong or has developed a hole in it.

Sorry I didn't read every word of your post, so I may be missing information.

Could be a clogged main jet in one of the carburators. Some seafoam or gumout in the gas tank can never hurt. If you have the mechanical knowledge, go ahead and take the jets out and check them for clogs.

89500inPA:
That was the diagnosis from the shop in town too...clutch issue.  I can't rule it out, and maybe I cured all of the other engine issues by making sure the spark plugs were in good...not sure.  The cable didn't really get disturbed much from the carb work, but that could still be it.  Would any of this be something that could appear "all of a sudden" before any tinkering with the carbs?


adidasguy:
I'm pretty sure there's enough gas in the tank and the petcock is on during everything above.  I've not had any change by switching this to reserve...unfortunately, probably not as simple as this, as much as I'd like it to be.   Somewhere else in this forum I found that the Haynes manual diagrams (at least in one spot) were wrong for my model, but even armed with that knowledge it turns out I had everything correct anyway (I checked my routing against a Suzuki part blow-out diagram, which turned out to be correct).

The vacuum line on the petcock however...I hadn't even considered anything with that.  I will analyze that closer for sure. 


Bluesmudge:
The details in the post didn't really detail the carb work I put in...but it involved taking the jets out and making sure everything was fine there...everything to do with the carbs looked pretty good even before cleaning.  I had considered throwing an additive like that through, but since I had just cleaned everything manually I figured it wouldn't probably get much that I didn't...especially since what I cleaned looked like it was already clean as it was.


I really appreciate the help everyone, for sure.

I think next, I'm going to go through the Haynes process of making sure the clutch cable is setup properly, just to be sure that's not it, as well as the vacuum line on the petcock.  I guess I'm also wondering if it would just be a good idea to take it in to have the carbs sync'ed and all of that fun stuff I don't have the equipment to really do properly too.  Is it possible that I just have a few things out of adjustment that are all just working against me at the moment?

Could be a couple small things all adding up.......

If it's a clutch issue, once you get to your top speed at WOT, the rpm's will continue to rise but you won't go faster. Sounds like you're running lean to me though (from what I skimmed thru on my phone). What jets do you have in now? And have you checked compression, valve clearances, and strong blue spark?

Pretty sure you have enough gas?

Dude, looking in the tank tells you Nothing. That's cause the tank Looks like there is plenty of gas when there isn't.

So, before you go Ripping anything apart, go fill the bugger up. And reset the trip meter to Zero when you do.

IF it solves your problem, ride until you hit reserve - loose all power again, blah blah - and have a look at the distance you have gone. At this point go fill up again, reset trip meter and repeat. Once you have two distances known, you have a good idea of the likely range you can get before hitting reserve.

Try filling up first, it's the easiest thing to check. Move on After that has been checked.

Michael

Big Rich:
What hints at running lean?  The biggest reason I ask is that the Haynes manual suggests that carbon buildup on my spark plugs like that shows that it's running rich.
I'm not sure what jets I have in now...they're what I got with the bike.  They may or may not be stock, I'm not sure if one of the two previous owners did anything with them or not.
I haven't checked compression or valve clearances...those were things I'd figure I need a shop to look at, at least for now.  I was wondering about these things too though.


mister:
The only reason I haven't mentioned much about gas being an issue, is because this all started not long after I had filled up.  During the course of working on it, I did end up setting down the gas tank at a bad angle that allowed lots of gas to drain, but that still left me with at least 1/2 of a tank.  The reason I say "pretty sure" is because I never even looked in it...I've simply had the gas tank off so many times recently that I can feel the weight and slosh of the gas in there.  I'm "pretty sure" that I've still got at least 1/4 of a tank...but I don't have any real way to gauge it.

I'd love for this to be the problem, and nevertheless I'm still going to add fuel and try the various positions of my petcock to see if anything improves, hoping it will help.  Since I am a relatively new rider, and I haven't really ran out of gas on the road...I'd have to imagine that if I weren't getting fuel because of needing to switch to the reserve that I'd only be able to have the thing run for a short time that way.  Though, maybe adidasguy is onto something with the petcock itself being a potential culprit, which could result in similar symptoms for a longer duration than expected.


Well...I'm off to check clutch and fuel systems.  I'll post any new info if I come up with anything notable.  Thanks again everyone for the ideas.  Every little bit helps.

I had a problem identical to this. It was ALL carb related. Clean those things out, clean your plugs again and I bet it will be fine.

Just adjusted the clutch cable to be sure that isn't an issue.  Having it start up and idle seems to be no problem at all in either on or reserve on my petcock.  In a short while (currently blocked in by other vehicles), I'm going to cruise over to the gas station and put some gas in it just to be sure and test drive a little more to see if problems persist.


xanthras:
This whole time, I've been leaning towards that as my issue too.  I'm still not completely convinced that there isn't a small piece of plastic stuck inside the carbs somewhere from when the T broke, restricting air or fuel flow or something...even after blowing everything out with carb cleaner, compressed air, etc.  I'd rather not do this again, but I too can't rule this out...though it might be better for me to take it to a shop to have the carbs sync'ed and have the mixture checked and all of that fun stuff too.

Was the bike sitting a long time before you bought it, as in longer than a month? Since you have only done 100 miles, I bet there is plenty of gas from the previous owner in there.

I ask because, if it is e10 gas then it could have easily gone partially bad in that amount of time. When I spent 2 months rebuilding my engine this winter and then tried to use the same gas that had been in the tank, I caused another month of trouble before I fully emptied the tank and put in fresh gas. Just because the carbs are clean when you put the carb back together, doesn't mean that they won't just suck more crap into them as soon as you start it up. Been there with two bikes now.

So, just as another thing to rule out, dump out all that old gas, fill it up with some fresh stuff, splash in some gumout, see how it goes.

Actually, a good way to help diagnose this -- see if it only bogs down under load. Put bike in neutral, let it warm up, then try to rev it to redline. If it revs just fine when not under load, then you know its not a carb problem.

Bluesmudge:
The owner before me claimed to use it as his normal ride to work.  He did bring it to me full, but while I was dealing with my initial fuel hose problem, I ended up slowly emptying my tank overnight because I left it sitting at a bad angle...had to replace that complimentary full tank very early on because of my ignorance and lack of forethought (I mean, I really should have just checked the damned thing before leaving it overnight ).  I've only been to the pump once so far, and today will make twice with it.

I'm also glad you mentioned something about revs in neutral.  I wish I would have mentioned this earlier since I did mention it to the shop when I called them, but the problem has only really shown up under load.  In neutral, it sounds essentially perfect.  Since I got the plugs back in and fired it up yesterday it has sounded probably as good as it ever has.  I can smoothly go from idle to redline once it's warmed up and it sounds great every step of the way...this wasn't the case before pulling out and checking on my spark plugs.  I was probably mislead to the carburetor because of my spark plugs, and now that those are secure and the engine sounds great in neutral...again I'm being pointed clutch-ward.

It sounds like it is/was probably multiple issues in concert...but it looks like the problem is being narrowed down at least.  I've just rechecked the clutch cable and adjusted the freeplay to rule those out.  If I take it out and still have the problem (which I'm assuming I will), it looks like I'll probably have to gear up for a clutch job.

I suggested running lean because of the 45mph top speed. If an engine just feels like it hits a wall, it can be running extremely lean. You said you one spark plug is fouled? It could be only running on one cylinder as well. That could also explain the low top speed / revving fine in neutral. Next time you have the tank off swap the coils left and right and see if the opposite plug becomes fouled.

Big Rich:
Gotcha.  Didn't know running extremely lean would act that way.  Good to know.

I had one plug fouled, and that was the plug that was in loose too (they both were, but that one was just barely tool-tight when it needed at least a 1/4 turn)...it probably was running on one cylinder for a bit.


I'm still blocked in, otherwise I'd have new info at this point, but the vehicle blocking me is also down for repairs...d'oh!  Kinda stuck at the moment (it's horribly hot though, so it's not all bad, I guess).

I've been thinking though, and I wonder if I might have had a problem with my spark plugs coming loose that gave me my initial problem, and in the process of (probably unnecessarily) working on the carburetors, maybe I changed the routing of my clutch cable enough to add too much tension; just enough tension to make the clutch never completely get released, as if there weren't enough free play.  When I made adjustments earlier today, it didn't seem off, but I went through with the Haynes procedure anyway and reset the adjustment at the handlebars then set the free play on the cable at the clutch side.  I'm hoping to at least see an improvement with this, but we'll see.

Well, finally got out for my test drive again...   I wasn't able to really get fast enough to test this before, but since I was able to get a higher top speed while I was out, I was able to find out that engine breaking was effective only sometimes; usually the faster I was going, the more of an effect it would have (not too abnormal yet, bear with me).  The part that got weird was at slower speeds.  It would feel like there was essentially no effect for engine breaking with gears 1-3.  If I got it up to 5th gear and came down, there would be a noticeable engine break as I went to 4, but from 3 down to 1 I might as well have not really been engine breaking at all.

Based on this, I'm going to have to say that I probably had multiple problems overall.  A spark plug problem and a clutch problem, and a possible minor electrical deal thankfully now only affecting the neutral light on the handlebars.

Thanks everyone for all of the suggestions.  I'll resurrect the thread if for some reason a new clutch doesn't resolve things...but I'd bet that's it.

You guys rock.

Keep us notified, I am intrigued by your problem and you I bet we would all love to hear once you get it fixed!

stokes776:
No problem!

I realize now too, I forgot to add a few things I noted from my last test drive...

My throttle had an effective range of about 1/4 (or possibly less) of the throttle.  If I rolled it on any further than that, it would simply sound like it was trying harder but not really moving faster.

I took some advice found somewhere else throughout the forum, and I got the bike up to about 35mph, and then I shifted up 2 gears from 3rd to 5th, and then tried to proceed as if it were a single gear change.  I was expecting some lurching, chugging, or some other non-normal outcome from the bike, but instead it seemed to shift right into 5th without trouble; very smooth.

Also, the operation of my choke smoothed out completely and no operates much better than when I originally purchased the bike.  This had to have been all part of the spark plug problem.

The smooth "bad" shift combined with engine breaking being very ineffective (especially compared to normal), is really what made me order new clutch plates and decide that was my biggest issue at this point.  Honestly, I expect that this will be my last issue for now, and things will be operating better than usual.  They will probably get here early next week, but while I'm waiting on that, I'm going to trace my neutral light to figure out why that decided to stop working again...

Update!

My clutch plates arrived yesterday, so I threw them into some oil over night to prepare them for today.  I ended up getting both the friction plates and the smooth plates as well as new springs, and just replaced everything.  The gasket was in horrible shape, the friction plates were obviously worn (some more than others, perhaps the reason for the lack of power in the first place), the smooth plates seemed like they were in good shape still, and the springs seemed to be in pretty good shape, but obviously slightly more worn than the new ones I was putting in.  Everything went pretty much as smooth as expected (removing that old gasket is a pain in the ass...though it was expected).  I put everything together, adjusted the clutch cable, and got everything going pretty much perfect....or so I thought.

I took it out for at test drive, and I found that it was slightly better, but not all that much better than before.  It took less "babying" to get it up to speed, and I was able to hop on the freeway and get up to a maximum speed of 69mph on flat ground.  When I started to bring it back home, I noticed that my clutch lever was loosening.  I figured that I probably didn't get a lock nut down all of the way...which is probably at least partially true...

I pulled the clutch release cover off, and went to loosen the lock nut and adjust the clutch release adjustment screw, but this time I noticed that I must have damaged the screw earlier: the place where the flat-head screwdriver goes into the screw was partially stripped in one direction (tightening has full grab, loosening is stripped, but not so bad it can't be used).  I tried to get the lock nut loosened and I couldn't budge it at all, so I loosened the screw and nut together and tried to tighten the nut further down the screw but it wouldn't move either direction...the lock nut is now effectively secured at the end of the screw, probably because of the stripped bolt.

So, for the mean time, I simply tightened the screw+lock nut down secure again, and I must have got it slightly better than I had before because when I took it for another test drive, instead of only having about 1/4 throttle with actual power, I now had power up to about 1/2 of my throttle -- Progress!

My plan now, is to replace the clutch release adjustment screw and its lock nut, and I presume that once I can get that set properly, my problem will probably be completely resolved.  Does anyone know if I can just back this screw all of the way out and pop a new one in easily?  I'm strongly considering, and will probably create a replacement screw/lock nut from whatever is available at Home Depot of the same size/threading/metal, rather than ordering a new one and dropping $10+ on shipping to get a $1.75 screw and a $1.25 nut for it...

Unfortunately, when I pulled it back into the driveway though, the engine died and now it doesn't even try to start...it almost acts as if there is only a slight charge on the battery, or if the engine kill switch were on because I don't even hear the starter try to turn over at all...no sounds at all, but I get my oil light on the console.  I'm guessing this problem is related to my other electrical issues that have started to pop up...


Good progress, seems like I'm narrowing down the issues and learning a ton about the bike in the process.  Gonna cross my fingers and hope for the best for tomorrow.

Just because lights come on and horn may sound does not mean the battery has enough oomph to start your bike. If you have a charger, pop the battery's caps, make sure enough liquid is in them, and charge it up.

If your battery is not charging while you are riding, all spark, lights, indicators, etc., will be drawing from the battery and eventually flatten it.

Michael

mister:
Yep, that was my initial thought too.  I'm just assuming the worst since one of the previous owners did a few customization with the electrical (new headlights/tail lights/turn signals/etc.) and it's kind of obvious that the job wasn't perfect.  I typically start with the easiest and most likely thing first though (like charging the battery).  Now that I think about it...the battery was another upgrade...it's an aftermarket solid-state battery of some kind.  It at least eliminates the possibility of liquid in the battery, etc.


I guess my biggest unknown at the moment (that I guess I'm probably just going to figure out in a few minutes) is if it's okay to just back out that clutch release adjustment screw all of the way and pull it out or if that will somehow be detrimental.  It seems like it would be alright, but I'd hate to find out that I have to pull off the crankcase cover to reassemble something because that screw was no longer holding it in place.