Engine Rebuild

[Burk Ferden]

I've got my good ol' 1980 GS850G and it seems to be leaking oil from the cylinder head cover. I purchased an engine gasket kit and was going to replace that gasket. My friend who is helping me on this cafe project says that we shouldn't replace any of the other ones if we don't have to. I kinda disagree with him.

I was thinking about removing the engine and working on it outside the frame because I wanted to black out some of the parts. I know doing this properly would involve disassembling the engine and essentially rebuilding it. Now I can take apart a lot of different items and have had success putting them back together. I am just afraid since I haven't rebuilt an engine before if there are any tricks or parts you have to watch out for. The only thing we are afraid of if taking apart this working engine and ending up breaking something.

Is this a good idea?

Justin

[DanTheMan]

If you're going to take apart an engine, and have never ventured into that territory, get some help from someone who has, or, at the very least, have the books (tech manuals) to help you out. Otherwise, I would advise against destroying a perfectly good running bike. JMHO

[Burk Ferden]

I have the clymer manual. I'm believe it talks about removing the engine from the frame, but I'm not sure how much detail they go into when it comes to taking the engine apart. (hopefully a lot) I was wondering if by taking the engine apart there are parts that you HAVE to replace by disassembling it. Like the crush washers in brake lines, you have to replace them when replacing the lines.

[TheCafeKid]

Indeed. You will need many special tools to do a complete true rebuild. Plus replacements for any parts you find out of spec, plus your normal replacements for breaking down a motor. Its not something i would do to a working motor. If there were a problem, i would certainly attempt it myself before i paid someone to do it, but i would just replace what leaking gaskets you have, and enjoy the running bike. just my opinion however.

[Burk Ferden]

Thnks, I guess I'll start with the cylinder head cover and go from there.

[spyug]

I've got to agree with the others...don't dissassemble that engine if you don't need to. Engine rebuilding is not something to enter into lightly. It is not difficult but there is a lot of knowledge you need to have or learn to do it correctly. If you are interested in persuing that I'd pick up something that's seized or known to be broken to work on.

By all means remove the engine from the frame for degreasing, painting and detailing. it will make it easier to do a good job. You will also be able to detail the frame and do any wiring cleanups or repairs. While your at it, you should pull the brakes and clean and adjust them along with the chain. Also check your wheel and steering head bearings and lubricate all cables and drives for speedo and tach.

Lots to keep you busy and out of trouble.:-D

Good luck with the project.
Cheers,
Spyug.

[Kcwiro]

I did not know jack and had never myself taken a engine apart when I bought my bike. I had a good amount of leaks and challenges.. in my case my compression was at like 90PSI per cylinder *far from where it should be* a rebuild was my only practical options....given if I had known what I know know I probably would not have bought this particular bike and just kept looking however I have made positive use out of my experience.

If you are just going to do a top-end rebuild (as I did...pistons, rebored block, replaced everything in the head except the valves themselves they were ok) a manual and some specific tools followed by common sense and patience is all you need. The guys here were very helpful to me when I did this work.

Advice I can suggest if you choose to do it is use assembly lube and don't use plain oil when you get ready to fire it up...also take the time to clean all the junk off the head and block... much easier when engine is in pieces anyway to clear it all up. BAG and TAG..photo's if necessary as you take down things...if you have the engine apart for a month or two it is easy to forget what went where so pay attension. OVERSIZED hose clamps make it easy to get the rings back into the cylinders and your less likely to break a piston ring *I did and I had to buy whole another piston assembly becuase they did not just sell rings #$@#* the weight of the block and gentle tapping gets them right where they need to be easy peasy.

Last thing I can think of Have fun and enjoy the learning experience..oh also beer and food works well to influence a buddy to help you at least cleanup everything...plus it helps pass time *we spent four hours alone cleaning off gasket material* also 'two heads are better than one :-D' I had other pitfalls from my own stupidity too but likewise I learned and will not repeat some of those mistakes ever again.

Good Luck!