I may be getting a bunch of miscellaneous parts off a 2002 GS. Wheels, tank, plastics, seat, engine, brakes, maybe something else- $200

The guy said that the engine has its head off. According to him, the previous owner took it off to replace the head gasket, but never got around to fixing it. This guy never put it back either.

I wonder if there is anything I can look at to tell me if the engine is still good. Can I pull on the piston rods and feel for a play? Look for signs of anything on teh cylinder walls?

Jenya

Your motor sitting with the head off, gonna have to yank the cylinders and do base gaskets as well ...
You pull the head off and you remove pistons and eyeball the rods, look at the rod bearing area on the cranks and wiggle them, look for shake, play etc etc ...

Take off the pan, and look under and in the counterbalancer area and in the crank end journals ...
Then maybe find on of the oil passages that go to the head, close up all the rest with rubber plugs and put air in them ... if it holds a few psi and you slowly rotate the crank and it stays that way .... you're looking at a good motor.

BTW I made up that last air part just as I was typing this ... logically will work ... practically ... may not ...

Like those - tank coating BS products that say ... after you do this and that completely dry the tank (WTF morons ... have you ever dried a tank fully ... peckerheads) or fill with fuel after treatment to avoid flash rust from forming ... aka ... this crap dont work ... we fill with fuel and watch it rust from the alcohol in fuel.

I dunno you could have a great motor and a slipping transmission ... though GS transmissions hold up well.
Cool.
Buddha.

I ended up picking up a bunch of stuff off a '02 GS for $200 - carbs, tank, wheels with tires on, brakes, miscellaneous small stuff and an engine.

The piston rods do have a play. One has a lateral play of about 1mm and another has a radial play of also about 1mm. I figured it may be a neat way to learn how to work on engines, while keeping my old '93 engine running. 

Considering the play of rods, is this engine a toast or a further investigation is needed? Is it time for splitting the crankcase? Is it a pain in the butt job? Seems that people try to avoid it as much as possible?

The carbs and the tank will go on my '93 soon. Are the brakes on the '02 bikes any better than on the pre '96 bikes. Should I  even bother swapping the calippers?

And another question - do the 2002 cargbs have curved sliders? The guy I got all this stuff from probably has a dozen different motorcycles in different stages of disassembly. It took him a long time to locate these carbs. They do look like they are off the gs500, but they a bit different from my '93 carbs. One thing that is very apparent that the sliders on these cargbs are curved, whereas on my '93 carbs they are flat.

I took a look at the bikebandit diagram - http://www.bikebandit.com/assets/schematics/Suzuki/SU0085_014.gif

The carbs I've got have a disk between the return springs with two cable hookups. The diagram doesn't seem to be showing it.

Any advice is greatly appreciated,
Jenya

nothing at all? Somebody should be able to answer something? I know Buddha does.

1mm at the pin end is nothing ... I'd say it a good motor ... sping the thing by the rods ... bad rods will make a clicking sound. You can in fact fill oil in it and sping it and it should go round and round quietly ...
Cool.
Buddha.

Well, actually, I was checking the play from the rod end, pistons excluding. Instead of pushin on the pistons, I was pushing on the rods.

What about the brakes. Should I swap my '93 calipers with the 2002 ones or it doesn't matter?

Jenya

I dunno what you're saying ... motor was doing what ... I wasn;t talking about piston at all ... were you moving the rod touching the pin end or the big end (the crank part) ... if you're moving it by the pin end and it moves 1mm, its not bad. If the thing moves 1mm at the big end in almost any direction ... you have a paper weight ... or send it to me, I can determine what flavor of "horrible death" it needs to have.
Essentially hold crank with 1 hand to keep from turning. Hold rod with other hand right next to the crank journal. Move it up down ... left right ... front back ... it should all be very very little ... then yea it will retain oil and run under load. if it move 1mm there ... its dead, forget all else ...
Cool.
Buddha.

Okay, I am confused now.

What difference does it make where you move the rod - at the crank side or under the piston. It is a continous chunk of metal. Seems that if it moves at one end, it has to move at the other. 

I do seem to be able to see that the rod bearings ( forget me if I don't get the terminolgy right yet) move when I yank on the rod.
What can be the reasons for that and why would that constitute a "horrible death"?

I wouldn't mind taking it apart and see how things are there, with some guidence of course.

well?

Are the rod bearing allowed any movement in respect to the crank at all?
If there is a movement, does it make the whole engine a paper weight?

Quote from: Jenya on November 21, 2008, 03:08:11 AM
well?

Are the rod bearing allowed any movement in respect to the crank at all?
If there is a movement, does it make the whole engine a paper weight?

if it moved independant of the crank, whomever is in posession of that crankshaft/rod assy. is in for a rebuild. or the rod, exiting the surly bonds of earth., there is room for a bit of a gap, but, not visible pretty much, nor is it usually felt easily

Yamahon - the rod has to move on the crank, just how much is the Q. The clearance is needed and has to be right for oil film and pressure retention. If its not, it will make contact and gall the bearings.
Jenya ... rocking the small end is amplified by the length of the rod. Move the small end 1mm, and at the crank it could be 1/100th as much. That is allowed. Your big end moved 1mm you'd never keep oil pressure in it. Its dead.
Cool.
Buddha

Sorry for being dense.

You write "Your small end moved 1mm you'd never keep oil pressure in it. Its dead."
Did yhou mean to say "Your BIG end moved 1mm...It's dead."

Now if this engine indeed is dead, what would it take to revive it?
New rod bearing? new crank?  Both? Is it still worth of splitting the crank and figuring out what is wrong with it?

I really appreaciate all the input,
Jenya

Fixed.
Dont take it apart. I'd take it to an engine shop and ask them ... but then they may lie to you ...
All I can say ... my savage motor I could move the small end ~1mm. That was running before I split it. Its problem was that the cam chain was hacking up the engine case - common problem. That motor ran great after I put back together too.
Cool.
Buddha.