Well i dont like things to go to waste guys and i had already started on my own motor so i finished it up. Entire motor is in pieces and everything looks surprisingly awesome inside. Everything is pretty spic and span with one single exception. The right piston rod bearing looks a little weird. I will add a picture of this phenomenon. However, I really just do not seeing this being a huge problem, at least not the kind of problem that would make the sound i have been hearing. Take a look at the attached photo:



I also have a picture of the pistons themselves. Seem normal, if not pretty dirty. I know you can tell a lot from the way the carbon deposits are shaped and all but im not sure what to look for:



So at this point, i can only think that maybe it is the rod bearing. However, like i said, it just doesnt seem like such a small thing could cause my problem. Literally, the entire motor is apart and everything looks awesome. The only thing that was not taken out was the valves. Should we look in to these as well? could those be a possible cause of my problem? Any help would be greatly appreciated guys. Im ordering a new gasket set tonight and then hopefully whatever new parts i need tomorrow.. Thanks in advance!

Wow. That is quite the project. That's a bit beyond me (bearings) so ill defer.

Weed, with my schedule that would be a winter project.

Sir, I'm going to need you to work on your time management skills

As for the bearings, if you can see the copper in the bearings then the coating has been worn off and they are no good.

Uneven wear patterns on shell bearings are usually indicative of something being misaligned or out of true. This could be something as simple as an incorrectly torqued cap all the way up to a bent or incorrectly machined crank/rod/case/cylinder.....or just about everything else 

Some info in this guide. Sec 9.7

http://epaper.mahle.com/mc/onlineCatalogue/2062863636375&lang=en

I am looking hard at the lower cap in the first pic.......Maybe its just the pic but compared to the top cap it looks like its tapering upwards!!!.

Please take a look at your starter clutch, there are three bolts in the back of the starter clutch "plate" where it is bolted to the gear. http://images.cmsnl.com/img/partslists/suzuki-gs500-2001-2002-usa-starter-clutch_bigsuusa92664_0123.gif

If those three bolts get loose (they do a lot of times), they can make that sound.

I know from experience:
http://img153.imageshack.us/img153/8528/lgim0010x.jpg

Gasket set is on the way guys. Will also be replacing the rod bearings. Also, thanks for the starter clutch hint. I'll look in to that. I figure that if the problem isn't some type of mechanical failure then it must be a loose part, in which case the problem should be solved upon reassembly since I'll be torquing every bolt to specs.

I have a feeling that Friction Burn is right.  Good luck with your reassembly.

Hey guys should I replace the rod bearings for both piston rods? Or just the damaged bearing? Thanks.

Just a humble opinion....

Given the effort required to crack open the engine....
....while you are in there replace EVERY bearing you can. If you have to ask or are unsure --- replace that bearing.

Do you ever want to have to go back in there again?
        Or would you like to have the equivalent of a brand new motor?

And I'd hone the cylinders and replace the piston rings, too.

Addidas said everything I was going to say. Treat it like a full rebuild.

There is just one problem with that idea. The con-rods, have by now been "stretched" a fair bit, so they are weaker then when the bike was new. Replacing piston rings, valves etc, will make the "bang" harder than it is right now. Now I know I am going to get sniped for this, but this opinion is based on multiple engine rebuilds (GS500's and GS450's).

I would replace only the damaged bearings, these engines have the capability (when treated right) to make the odo go round and round, without replacing bearings. Replacing all the bearings, piston rings, honing, will cost a pretty penny. The fact of the matter is, most parts have been "stretched" by use, so the idea of getting the equivalent of a brand new motor, no way. These -are- Japanese bikes, the materials used are for one thing; cheap.

Just my opninion, based on experience.

OK. I'll ask. How can the connecting rods get stretched?

Nothing pulls on them. Piston firing pushes down on the connecting rods. Exhaust cycle pushes up on the piston. Compression cycle pushes on the piston. So with all cycles pushing on the piston and crank, how would the connecting rods get stretched? Seems they would get compressed - but given the hardness of the steel and the size of them, not sure how mush they could possibly compress (or stretch).

And it seems quite common to hone the cylinders and replace the piston rings and never worry about stretched connecting rods. You do that for low compression and never heard you had to replace the connecting rods.

`Stretch` is the term given when the big-end journal looses its concentricity. Its diameter becomes larger along the rods length than it is across it.

We are talking a couple of thou` at most and you simply wont see it by eye.

Sledge got it 

The conrod gets veeery small cracks in it due to use, now whats going to happen;
You are going to give the engine its original compression due to bored cilinders and new piston rings. So you are going to put extra stress on a conrod (and the rest of the block for that matter) that have already been run for quite a while, and are already (possibly) microcracked.

So in a newstate;
-New connecting rods
-Good compression, good bang

After a while;
-Little bit tired connecting rods
-Medium compression, little bit less bang

When old;
-Tired connecting rod
-Lower compression, measurable decrease in rear wheel HP

When replacing bore / rings
-Tired connecting rod / engine material.
-Compression like new, power like new.

Now anyway you put it, you are going to load old engine halves / conrods (the conrods was just an example), with new (more) power.

Not trying to take the piss on anyone here, have just heard this "replace x and y, and have new engine" forum advice before. If you want a new engine, closest you can get without -getting a new engine- is replacing all the rotating parts, and because that is way to expensive, people usually run there engines till death and buy a replacement. (which in the current form of production, is the best way).

Shadow Camaro; if you are going down this "total rebuild" road, please make sure your oilpump is still up to spec pressure, because people tend to forget, those wear down too.

Good luck   

Thanks for all the advice guys. But hey, I was wondering about that starter clutch advice. When I was disassembling the engine, it didn't seem like there were any loose bolts anywhere. If the starter clutch bolts were loose, or any other bolts for that matter, would it have been obvious when I was taking the engine apart?

The starter clutch is pretty well hidden in between the cog and flywheel, I did not notice this was the problem untill further inspection. So yes, please do take a closer look at that item.

Good luck.

I appreciate all the advice FB. I'll check on it after work. Now I have another question. I'm cleaning up some of the parts and I was wondering if water was okay to use? Is it going to rust anything?

I forget does the Haynes manual list the specs for Conrod length etc? Yes the bits can stretch but if you measure them and they are in spec and no other obvious damage no reason not to re use. And after you clean up your parts give them a light coat of oil or wd40 or what have you to protect from rust because yes they will rust.