I have a three part commute every day (home -> school ->work ->home) and when my bike was running fine until I started it up after work. The first time I started it, it made a clunking sound like something was loose and bouncing around inside the left (when you're riding) side of the engine. I thought my transmission was not quite all the way in neutral (thus bouncing around between 1st and neutral) so I hit the kill switch and went into and out of neutral. I started it again, and it still made the same sound so I shut it off again and took the plug wires off so i could hear the noise when just the starter was running. I tried that, and couldn't hear anything so I put the wires back on and started it up again (no more noise). Since then it has been idleing a little on the rough side, and whenever I get above 4k, my bike startes to vibrate like its going to shake itself apart. There are also a lot more vibrations than usual at lower speeds, but not as much so. I also feel a loss of power, especially above 5k; almost like it's running on one cylender but not quite as bad.

I have two thoughts and I am hoping for some suggestions from you all before I go any farther.

Could this just be a ignition problem? I just replaced my plugs the other day, but the bike was running fine until this happened. One of the plug wire is loose, so could it be as simple as replacing my plug wires and/or re-adjusting the gap on my plugs? (currently set at ~.029 inch or ~.9mm which is what my previous plugs were set at)

I saw this post about balance shaft bearings and I am really hoping that I don't have the same problem.

I have a 93 gs with 6600 miles on it.
Any thoughts or suggestions would be greatly appreciated. Thanks

Well, I talked to the service department at the local Suzuki dealer today, and I found out that the service manager used to race a gs500. I have only talked to them over the phone (I plan to bring my bike in there in the next couple of days to be sure) but they are of the opinion that I will need to replace the counterbalance bearings and the side covers (Am I using the right term here?). They have never heard of this happening to an engine this young (miles), and while I want to wait until they look at it in person; I'm planning for the worst and I want to figure out if I am going to be able to do this myself (they estimate at least $800 to fix it :x  :guns: ).

Is it a generally a good idea for someone to rebuild an engine with no previous experience doing so? I have worked on engines before and I have watched it done a couple of times, but I have never done it myself. If I do end up rebuilding, are there any upgrades that I should do while I have the engine taken apart? Would I be better off looking for a new (to me) engine?

Anyhow, it looks like I won't be riding for a while . And I just got the rest of the parts I needed to work on my brakes, too. *sighs, hangs head *

Now you all have to ride more to make up for me  :lol:

Any suggestions or opinions would be greatly appreciated.

Working on an engine is not that difficult. Having the right tools and enough time are usually the problems. I never had any real experience working on motors until I got the GS and everything worked out good. I started by reading a Clymer manual and eventually bought a factory manual as well. Got a Haynes manual the other day but have not looked in it yet.

but...$800...OUCH! You can get another bike for that price or at least a used motor for half that, which I happen to have one for sale very soon.

It would be best for them to look at it to verify what the problem is. Maybe once the motor is opened up, it turns out to be something minor.

Can't talk for the states, but in Europe usually swapping motors is the more economically sound path once you have one of the plain bearings go south. Problem is that usually the shaft takes a hit as well and has to be replaced. If it's just the counterbalancer you might just scrape by with cost of parts if you cna do everything yourself. As soon as the crankshaft is involved you are usually out of luck.
Bad thing about plain bearing damage is that their wont is to come in series. One takes the other with it by means of spreading debris around the oil circuit.

About this not happening to young engines: Plain bearing damage more often than not has its root in low oil level or engine overload with the oil not up to operating temperature. That can happen at any mileage. Plain bearings supplied with oil under pressure in fact have almost no natural wear, so mileage is not major determining factor in them getting damaged.

Left side of the engine... I thought the counterbalancer is on the right.... Left has magnet, stator coil, starter clutch, countershaft.... My money is on one of these damn things... all of which are easy to fix. Right side has crank trigger, counterbalancer clutch, oil pickup... that $800  is better spent on another bike and part this one out if it is the balancer.
Cool.
Srinath.

The counterbalancer is in front of the crankshaft, same length, thus has bearings left and right.
Though you are right that the damage is right more often than left, because it is often caused by a blocked oil path after changing the clutch cover gasket.

OK, so this is where I am at right now:

I had planned on bringing it to the dealer today, but one of the techs quit on friday, so I'm SOL there :guns:  :guns:  :guns: . The parts guy said that they won't touch anything older than 10 years anyhow (they didn't tell me that on the phone):x . The other suzuki dealer in the twin cities that I know of won't touch a bike that old either  :x  .

I found a place that will look at it, and I'm thinking I'm just going to pay the diagnostic fee ($75). I want to ride again, and I am not 100% confident in my diagnostic abilities.

It will take them about a week to finish the diagnostic, so I'm going to spend that time figuring out my options and planning for the worst-case scenario.

dgyver, when is very soon? Can you give me some more details about the engine that you will be looking to sell?

Is there anyone in the twin cities area that might be interested in helping with some major engine repair?

I would take it to another place than the dealer.  Sounds like they are guessing too much on it being the balance shaft bearings.  There are so many things that can cause the engine to run rough.  If they are willing to throw out a guess like that.  I imagine they are just looking to take your money.  Find someone that seems more honest and with good technical skills.

actually, thats just the estimate they gave me IF the problem was the counterbalancer bearings. They wanted me to bring it in so they could look at it and give me a more exact estimate.

Quote from: goatdgyver, when is very soon? Can you give me some more details about the engine that you will be looking to sell?

It should be available for sale next week. I will be testing the motor, tomorrow. Well actually today is tomorrow, ok Sunday then. I did not have a fuel supply when I was turning it over and then I broke the key again, hence my "hot wire" post. I get back with more details later Sunday.

Well, I heard back from the place I brought my bike. The tech there thinks that it is just a carb problem. I certainly hope he's right. I'm still a bit worried about the clanking I heard, but I'm going to go with the assumption that the tech knows more than I do.

I'm trying not to make this a rejet question, but what have peoples experiences been with carb work? I think I could do a rejet myself (from the tutorial I looked at), but I know some people who have worked on their carbs for months only to end up paying the dealer money to fix it when they gave up (and thats saying a lot, my friend NEVER pays someone else to fix stuff). He and other people have said that it would be easier  to just pay someone else to do carb work, unless you have done it before.

They want $225 + parts to dissasemble, clean and rejet. Is that reasonable? (the $75 diagnostic fee gets applied to this though, so its more like $150 beyond what I already owe them)

Sorry to make this sound like the same old, but I couldn't find any posts on carb work (not rejetting) and I don't know enough to know the difference.

Thank you all (also in advance) for your help

now that i think a little harder about it, how can it be carb problems? I know that my bike needs a rejet (has a full yoshi exhaust; I don't think it was rejetted) but wouldn't that have been a gradual thing?

This happened all of a sudden. It has been running fine since I bought it and all of a sudden started vibrating one day.

Can someone explain this to me? I don't understand. Thanks

For $225 they better at least give you a kiss before they screw you. It is possible a jet came loose and causing it to run rough but doubtful if they have not been worked on recently. They normally get stuck from the varnish build up from the gas.

There is really nothing to rejetting a carb...2 screws to remove the bowl and there are the main & pilot jets. Unscrew them and screw new ones back in. Takes about 10 minutes.

How much more difficult is taking apart the carbs to clean them and rebuild them? More importantly, how easy is it to screw it up (not the rejet, the rebuild)

I'd be happy to help with the rejet; I'm in Minneapolis.  But really, the best time to rejet is when your bike is mechanically sound.  If there are problems with the ignition system, or mechanical problems, then it will only be confusing trying to adjust the jetting.

Regarding the clunking sound, there's really no way that improper jetting should cause a metallic clunking sound!

Question for the experts here:  if he had vapor lock, and tried operating the starter, would that explain the clunking?  

Regarding the way it is running now (rough at 4k+ RPMs), if you were working around the synch screw, and bumped it, then that could cause vibrations.  If all you touched were the plugs and the wires, then I'd start there:  maybe the insulator cracked in one plug when you had it out, and at higher RPMs, the spark is fat enough to jump through the crack, and short.  Or maybe there is a similar marginal condition with one of the plug wires.  

I'd start with a new pair of plugs, and see what happens.  If that doesn't produce anything good, then you could try testing the plug wires.  For example, turn the idle up, and run on only one cylinder (for example, the right cylinder).  Try first one plug wire, and then the other on that same cylinder and coil.  If no problems are found, then repeat on the left cylinder and coil. I haven't actually had to do this to test plug wires, but if you can get the bike started on one cylinder, then I think it would work.

You mentioned that one plug wire is loose, so I'm suspicious about an intermittent short there.  If you watch it at night, you may even be able to see if the spark is shorting at the sparkplug boot on one wire.

Well, I re-learned an important lesson today. The guy that answers the phone doesn't always know what the hell he's talking about.

I called back to get this cleared up, and the guy on the phone says the same thing he did earlier. Then he offers to hand the phone to the tech that looked at my bike and I agreed. Here's what really happened:

my bike is running lean. I knew that already. a rejet was/is on my to do list. I hadn't looked at it much yet, but I guess its worse than I thought. the settings haven't been touched since it came off the line.

The tech started my bike and let it run for a while. The problem wasn't obvious (except for the fact that it was running lean) so he had the service manager (the guy I had been talking to) call me to ask for some details (which the guy never mentioned). I answered the questions and the tech said that he would take my bike for a ride tomorrow and get back to me.

So, I guess that I'll find out later (tomorrow, I hope). I'm just hoping that this makes a fool of me and it ends up being something simple (then I can take the hit to my pride and more importantly, I can ride again with minimal injury to the wallet).

My bike does start and run (like a sick horse, but it does run) on one cylinder, so that technique of checking the wires/coils would work. Yeah, I forgot to put one of the wires back on when I changed my plugs . Thats how I found that one out    .

Thanks for the advice everyone. I get the feeling this might not be over quickly, and I appreciate the help.

My wish has been granted. The tech says theres nothing mechanically wrong with my bike. If the counterbalancer bearing was shot, there would be more noise. He attributes the problems I'm having to bad plug wires and carb issues (needs a rejet).

So, now that I don't have to do any major engine work I can do some of the other things on my list.

Replace front tire (the rear one was practically new when I bought the bike but the stock tire (bridgestone excedra G)) I would like stickier tires, but I'll do that when I replace both tires.

rejet carbs. I know that there is someone else in the twin cities who is going to rejet. perhaps we will have a "rejet party"  :lol:  

Anyhow, now that my pride is limping along one one leg I can ride again without such a big hit to my wallet. I leaned more about my bike, too. I'd say the diagnostic fee was worth it considering I was going to replace the engine otherwise

Thanks again everyone for all your help.

Glad it worked out for the most economical way. We all have to learn one way or another.

The normal reason folks here rejet, is if they have aftermarket air cleaner and/or exhaust; or else  to speed warm-up (pilot) and to improve off-the-line performance (jet needle).  If your air cleaner and exhaust are stock, and the bike is running OK at idle, but poorly at half-throttle, then I think it is more likely that it is lean up-top due to crud in a main jet or needle jet.

It may just need a cleaning.  It's a miracle if it works at all after 11 years with no carb cleaning.

OK main jets are huge... probably wont get crudded up, the needle cant get crud up either. It has no hole... its a needle... Emulsion tubes can get some crud, but usually its too high and s`doesn't get crud in it.
Cool.
Srinath.