Quick question about a rebuild

[Simonak3000]

Hi

I made a post a few days ago asking about a new battery for my 1982 GS650 GL and I was really satisfied with the awsers I got so I might as well tell the whole story. The fact is, my uncle gave me this bike because he didnt need it and had another one. It sat in a unheated garage for close to 30 years and we are now restoring it, me and my father. We did a new paint job and are currently working on the electrical system. But concerning the engine, we have no idea in what condition it is on the inside. So what work should I do on the engine/clutch/carb In order to make sure its in full working condition and be on the safe side? I dont have a lot of experience but I want to learn!


concept moto.jpg
Thats the new paint job, we still need to apply the stickers(what you see on the picture are just pieces of paper), change the tires and of course, engine/clutch/carb work.

L.Leblanc

[Rich82GS750TZ]

Cart's a little before the horse on this build, I think, painting and stickering before knowing if it'll run. Hopefully you've at least rotated the engine to determine that it's not seized. If you have, and are relatively certain that you have decent compression.
Download shop manuals from Bikecliffs website linked in my sig
Adjust the valves. (find a tutorial on Bikecliffs website linked in my sig)
Full Carb Clean. (find a tutorial on Bikecliffs website linked in my sig)
Check for proper petcock function/vacuum.
Change Oil and filter
Change air filter
Ensure all air intake to carb, carb to engine, and exhaust connections are air-leak-free.
The clutch will let you know if plates are stuck together or springs are shot.
BRAKES: - At the very least, new fluid and brake pads. Calipers and Master Cylinders may need overhauled/new parts. New Stainless Steel Brake lines are highly recommended.

[Simonak3000]

we know the engine turns, we just need to know what to check to make sure it will work adequatly. But your awnser is perfect thanks!

[Rich82GS750TZ]

Great. And welcome. And your welcome. I put valve adjustment at the top of the list for a reason. You do not want to attempt to start the engine until you know that valve clearances are w/in spec. Also, looking under the valve cover would give you an opportunity to look at things on top for any visual clues to any prior damage. You can't see the valves, but can see if each bucket has a shim, etc. When checking the valves clearances, follow the tutorial you'll find on Bikecliff's site. Do not rotate the engine without a shim (or at least a quarter) in every bucket, and always turn it in a clockwise, forward direction (as you're looking at the right [throttle] side of the bike.)

There is a member here, goes by Steve. Find him and email him, asking him to send you his handy dandy valve adjustment spreadsheet to make this process easier. He's also a wealth of knowledge on everything else. Lots of other great contributors here as well, who will help you with your build as you need it. Post new threads in the appropriate section when anything new comes up. Create a signature with your bike year and model in at (at least), then you'll never have to type that again. And post lots of pictures.

This post is also a very good place for you to start:
Top 10 Newbie Mistakes

Just about everything you could possibly encounter has already been dealt with by someone here.
Tip on using the Search function of the site:
Click Advanced
Type in your keyword(s)
Search Titles only
This will yield much better search results than searching entire posts

[Nessism]

Red flag on the pods unless you installed a Dynojet kit to compensate for the rejetting needs.

The engine is most likely fine. Like mentioned, check the Newbie mistakes list and make sure you take each item seriously, like carb rebuild and replacing intake boot O-rings. Short cuts are long cuts.

[chuck hahn]

To add a few things to whats already been mentioned.
Twist the big knob on the cam chain trensioner counter clockwise just a little to reasonably assured its not stuck.
Pull the plugs and squirt a little oil in the jugs and use wrench to turn it over. This will coat the liners with some oil. Also do it with a wrench to FEEL if any piston hits a valve that may be stuck or whatever. IF it jams up DO NOT force it. Dont use starter because the starter wont stop for anything and will for sure bend a valve.
IF alls well do a compression check using the starter and hold the throttle wide open, This will tell a lot about its health. See the service manual to see the acceptable PSI range. IF one jugs low..or not as high as the others dont panick. May just be a matter of a valve too tight and holding a valve just a few thousands. Adjust valves and recheck the compression.
Valve stem seals are almost assured to need replaced after 30 years. IF it smokes on start up and clears up after a while thats a indicator of them leaking. Once is sat a while and it again smokes then clears up the they leak for sure.
And lastly, if it smokes on start up remembers theres probably a little oil or old gas thats seeped into the pipes,,,this needs to be burned out too before youll be able to let it set to see if oil again seeps paste the valve stem seals...make sense?

[Nessism]

Since the engine has sat a compression test may not accurately assess the condition. I'd adjust the valves as mentioned before and then do a compression test if you have the equipment. If not, I wouldn't worry about it.

[chuck hahn]

Maybe not difinitively but a darn good idea as a jumping in point was my point Ed.

[Nessism]

Chuck, gotta adjust the valves first before compression test. Tons of hacks never adjust and the valves hang open until the compression falls.

[chuck hahn]

I mentioned hung valves. After rotating the engine manually ( and even with valve cover off to visually watch each valve open and close ) there is no harm in pulling a preliminary compression test to at least establish there is , in fact, at least the presence of some compression in all cylinders. And i agree the valves DO NEED CHECKED. NO argument there.

Im speaking of a preliminarey test....not as the final all telling test. Hypothetically lets say i pulled a preliminary test and there was no compression on say number one. OK, so i see if both buckets on number 1 will move with my finger and both do turn. That tells me that there is enough clearance for both valves to be fully closed ( may not be within specs but at least fully closed ) without any cam interference. So why would i need to adjust all the valves to find the no compression is (or isnt ) from a maladjusted valve. Theres more than one way to skin the cat.

IDEALLY yup adjust them within specs and do a check. Again i think you think im saying an initial test will say its good or junk...not what im implying at all.