92 GS500EN lower end

[arnermd]

Hello All,

I inherited a 1992 GS500 project, partially disassembled, and have found this site to be really helpful, a great resource.  I have the chassis mostly re-assembled and now working on the engine.  Head and cylinders are off, clutch is out, getting ready to split the crankcase to have a look at the lower end.

Two questions for the experts:
1)  Does anybody sell a seal kit for the lower end?  Or do I need to purchase each seal separately?

2)  As the engine sits now (head and cylinders are off) the rear cam chain guide (the one the tensioner pushes against) is free to move up and down about 1/4 - 3/8".  Is that normal? I am wondering if the cushions might be missing and that's why there is so much room the guide pin to slide up and down in the slots.

Thanks for any suggestions.

[The Buddha]

I dont think the cam guide is able to move up/down 1/4". 1/4" is huge in terms of engine parts. Where it sits in the cases, look for wear.
Also you sure you can get the bearings for it ? In the back of the engine - on top like the part that's under the airbox you'd see a set of letters like ABBA or something. No they're not fans of a 70's euro pop group. They denote the thicknesses of the bearings that were installed. You'd have to turn and polish the crank and get the right bearings for that new spec. Usually you're working in 10,000's of an inch in case of bikes. That's where all the unavailable parts etc etc come in to bite you.
However if the bottom end isn't bad (no rod knock, no broken counter balancer bearing etc etc), I'll just leave the bottom end alone.
Cool.
Buddha.

[arnermd]

Cam guide:  1/4" of vertical movement seemed like a lot to me as well, which why I suspect something is not right.  Maybe the cushions are missing.....  Need to split the case to really tell.

Bearings:
- One of my jobs is designing hydrodynamic bearings for pumps, so I am familiar with tolerances in the 0.0001" range, your comment is well received.
- I looked on the back of the crankcase Counter balance codes are A-B, Crank codes are A-A-A-B  (too bad, no ABBA)
- Suzukipartshouse and ronayers.com are both showing green / black / brown / yellow bearing availability.  Hopefully they actually have some stock.
- I do not know if there was a knock or not, when I got the bike it was in pieces, I was told it ran when it came apart.....
- Plan for the moment is to open the crankcase and have a look.  If it looks bad it may be then end of project, unless I can find parts.
- If it looks good I may try measuring clearances with plastigage or I may just see if it "feels right" and take my chances.....

Seals:  I figure it would be downright foolish to put it all back together without new shaft seals....  hence I am looking for a full set.  Have not found one yet.

Thanks for your thoughts.

[Bluesmudge]

There was an OEM gasket kit, not sure if Suzuki still sells it. There are aftermarket gasket kits. No seal kit I'm aware of though. Is pretty uncommon to do work on the bottom end of these bikes so a complete seal kit wouldn't sell. Few people have the skills to feel confident cracking the case open and even then, it doesn't always pencil out vs throwing in a used motor.

[The Buddha]

Athena gasket kit was what suzuki used to sell IIRC once they started the Spain manufacturing ~2000-01. Athena was a spanish company I thought.
I've bought a couple of those cos it was $20 or so back in the 00's and the valve cover gasket alone was $26+ from suzuki
Cool.
Buddha.

[arnermd]

Split the case tonight and lo and behold the cam guide cushions are missing, which explains all the vertical movement in the guide.  Not sure where they went....  I did not find them in the pan or anywhere else.

Visually inspected all the bearings and journals and they look great, except for the countershaft left (generator) side.  I saw some wiping and a touch of smearing there.  Is that typically the "problem" bearing?

[The Buddha]

Split the case tonight and lo and behold the cam guide cushions are missing, which explains all the vertical movement in the guide.  Not sure where they went....  I did not find them in the pan or anywhere else.

Visually inspected all the bearings and journals and they look great, except for the countershaft left (generator) side.  I saw some wiping and a touch of smearing there.  Is that typically the "problem" bearing?

I'm not an expert there, I am of the belief that all counter balancer bearings are "problem" bearings. So left, right, top, bottom, middle north, west, south, east all of them are problem. I hope you figure out and get the right bearings. If you cant do it, no one can LOL.
Cool.
Buddha.

[arnermd]

Well....  not a good weekend for the project.

- All 4 valves are bent....  Tried to straighten one of them and I heard a sharp "crack"....   in the market for 4 new valves now....

- Checking cam clearances with plastigage and found one of the cam bearing cap bolts holes is completely stripped, will not even get to finger tight.
    - Thinking about a helicoil repair here but I am concerned about messing up the pilot diameter for the sleeve that locates the bearing cap.....
        - Just checked on this and the thread is M6x1, looks like the drill size for this helicoil is .248" and thread OD is .311, which is smaller than the OD of the dowel @ .314".  It should work!? I think....
        - How long should the helicoil be?  Is 1.5d long enough?
    - Other option is to buy a used head with the valves....  concerned because who knows what condition it is in.  May be worse than one I got.
    - The cam clearances measured OK, even the one with one bolt on it..... 0.002 - 0.004" (allowable is .0059")

[Bluesmudge]

I doubt a used head could be in any worse condition than 4 bent valves and a stripped bearing cap bolt hole. You may be able to find a decent head for less than the cost of 4 new valves from Suzuki.

Its been a long time since I've had the top end apart on a GS500 but based on your measurements it sounds like the helicoil will work. You could try it and if it seems wrong then you are only out the price of the helicoil and could move on to the new head idea.

[arnermd]

My concern about buying a used head is warpage, cracks and cam shaft bearing wear....  hard to check for that online.  you have to trust the seller, who may not even know what they are looking for or how to inspect.

A set of new  Suzuki valves is pricing up at $182...  which seems like a lot but I have not found any cheaper or any used / aftermarket alternatives.  If you know of any please let me know.
   - I did find aftermarket valves by Vesrah for slightly less.... $150 for the set.

Used heads are pricing out at around $200 and many do not include valves, condition unknown.  New heads are $500 and do not include valves.

At the moment it seems like my best option is to repair / rebuild what I have.  Thanks for your thoughts.

[The Buddha]

There was a company cant remember the name of it right now - But it was in CA - they used to make high quality valves out of inconel. It wont likely be any cheaper but maybe better than the suzuki and likely vesrah.
I know a lot of kawi's have the intake valves receding into the head problem. The suzuki valves were a lot better, but these are guaranteed better.
Oh yea Kibblewhite - That's the name of the company - 1 sec.
https://www.kpmi.us/

Contact them and see if they make em.

Cool.
Buddha.

[arnermd]

Not finding anything from Kibblewhite that fits....  but I did find Summit racing sells Vesrah (GG-3024-IN/EX) valves for $20 / $27.  So that puts the set of 4 at $94.  A lot less than OEM....  Might be my best option.

These valves any good?  Not that I plan to run the thing hard or long....  might just be good enough.

[The Buddha]

Street bike valves have to be made from solid inconel and swirl polished. That's about it. No need for Sodium filled, necked down in the stem or this or that nonsense. Those are all race bike spec valves. BTW Check in with Bluesmudge - he's likely shopping for valves too.
Cool.
Buddha.

[Bluesmudge]

Yup...just confirmed that at least one exhaust valve is bent. More than .50 mm valve clearance. Somehow the intake valves seem like they are still in spec. I haven't dug into the engine enough to know if there is damage beyond the valves and cam chain guide. There is a

There is a machine shop guy near me that makes custom valves and does top end work for the 80's Suzuki GS bikes, I wonder if he would make valves for the GS500 and if they would be any cheaper than Suzuki valves. If you want to go crazy he also makes Titanium valves. They are $1000 for a 4 cylinder bike so the GS500 would "only" be $500  His ebay store is "smw70ss" or Schumann Motor Works on Facebook.

[arnermd]

Yeah.... 500 for a set of valves is not in the cards....  This project is more for fun, I have no real plans for the bike when I am done.  I enjoy working on and fixing things so this is therapy for me.
I checked the summit website and they list the valve material as steel, maybe that's correct, maybe not.  Vesrah website does not list the material.

In other news I put the case back together last night to measure counterbalance and crank clearances.....  not good
- Crank clearances were all about 0.003 (service limit in the manual is .0031).  So looks like I am doing bearings.....  Question is which ones, I found the stampings on the case and crank so I know which ones should be used when new.....  gonna see if I can mic up the journals and bearing thicknesses this weekend.....
- Counter balance bearings are well over .003 (plastigage scale does not go any higher).  Might try the red and see if I can get a better reading....  but they are worn out.  I can tell by looking at them.

Also found the case is missing three bolts....  wonder where they went?  The joys of working on an abandoned project somebody else has mucked with.....ha

I also was able to get a heli coil in the cam bearing cap hole.  Was pretty easy, the drill actually fit inside the dowel ID so that helped center it up nice in the drill press.  I drove the helicoil too deep but I torqued it up the other night to measure clearance and it felt fine.  I am going to call it a success, but not perfect....  Clearance was good too.... Good enough!

This forum really is awesome....  tone of great tips and advice in here.

Another head scratcher....  I used the online parts diagrams to identify where the case bolts go.  When I tried to install item 13 it bottomed in thread before clamping on the head... like it was too long.  I check the hole and there is nothing in there and the threads are fine.  I measured up the casting and I fail to see how a 70 mm long bolt could possibly here....  it is just too long.  A 65mm bolt works fine....  I find it hard to believe there is an error in the parts list....

[arnermd]

crank case parts diagram.....

[Bluesmudge]

I wouldn't put it past Suzuki to list the wrong bolt. They have listed the wrong sump gaskets for certain years and also show the tank petcock mounted backwards in the manual and parts diagrams.

[arnermd]

I think I got it figured.....  they switched 13 and 14 in the diagram.  When I swap those two bolts everything fits up fine....

Odd thing is for my model (N) they list 14 qty as 0.....  but for models (R/S/T) qty is 1....  IDK...  I am not going to lose any sleep over it.

[arnermd]

Need an opinion from the experts....

Found a chipped dog on the 3/4 drive gear where it engages the 6th gear.  Torque should be pretty low in 6th gear....  right?

I really do not want to press off the gears to replace it.....  what do you think?  I am tempted to let it fly....

[The Buddha]

OMG, I doubt any one has got this far into a GS transmission.
Cool.
Buddha.