Opinions on rebuild or replace

[wymple]

So I REALLY like my 81 850G. I picked it up with the odometer in the middle 30's, and it runs great. However, I believe it was never well maintained (the whole bike) and oil misting and tiny leaks bug me. With the odometer now in the upper 50's I believe it's a candidate for a rebuild, which is not a concern as I will not be selling it. The thing is, I think with a little shopping and some luck, I can find a really solid 1100 to stick in there. Who couldn't appreciate another 20 horses and some more torque? I'm not sour on the 850 output either way. Also, I think the 1100 has a little higher final drive transmission, a good thing to me. I'm thinking it wouldn't set me back a whole lot more money than a correct overhaul of the 850. Any opinions on the swap?

[Rob S.]

I've complained to my mechanic about oil weeping also. He always says, "If it ain't broke, don't fix it."

Might be cool to see how high you could get the odometer without a rebuild. Just sayin'.

[loud et]

Its certainly a numbers game. To rebuild the 850 requires a number of basic parts and they add up quickly.
Head and base gasket. Valve cover gasket. Valve seals. Cylinder hone. New piston rings and circlips (usually suggested) and a number of other rebuilding bits. In my opinion, why put money into your baby if you are not gonna treat her good....meaning new ss bolt kit for the engine, new ss exhaust studs, new plugs, plug wire ends, a few other case gaskets, 50$ in degreaser and paint to get the newly redone engine looking good and on and on. It really does add up.

But if you find an 1100 shaft that you KNOW is a solid runner with no leaks whatsoever.....thats a hard one to find. You may end up tearing halfway into the new engine too and replacing some of the above mentioned parts.
Its all whats available to you at the time and how far you want to go. Do you just want a grungy, as is 1100 to swap in or do you want a freshly redone 850? Of a freshly redone 1100? lol

I think the 1100 shaft upgrade would be sweet. Its really a money game. lol

Enter dreamy music...... imagine looking at that shiny, fresh painted 1100 engine you swapped in. A good going over, valve adjustment, carbs tuned.....new air cleaner. Its a cool evening.
You start the bike for the first time and the extra horsepower blows some black carbon out of the old exhaust....you feel a new vibration in the handlebar from the new horsepower as you crack the throttle. It already feels like a different bike. You hop on, and with the first full twist out of the driveway you know you made the right choice. Your forks extend, your arms straighten from the pull... You are already smiling and your mind is saying "Oh crap, I need to uprade my brakes now" haha haha

Good luck, I hope an 1100 shafty engine comes your way.

[chuck hahn]

My take on any bike i get is this. I dont know anything about it and how it was abused. Thats the same theory I would use when getting a used engine. Said engine would be opened up and gone through, so whats the difference if you redo your current engine or get an 1100?? I would take the current one down and just redo it. get all the goodies on hand and be done with it in a day or two. But thats just me.

[chef1366]

I wouldn't mess with it unless your compression numbers are low.

[wymple]

Well, I thought that maybe with all the honesty and integrity of so many of the forum members I could find a tight, clean 1100. The only thing that bugs me about my current engine is a couple of drops of oil under the bike and that dirty mist that seems to build up on some of the fins, it's a visual thing. I have it jetted and running like a top, starts in a heartbeat hot or cold. Valves have a recent adjustment, weren't bad to begin with. Compression has to be OK, it pulls really good with snap. Down the road a little I may need a new stator and R/R. I'm not afraid to climb on and go cross country. Maybe I'll just keep cleaning it off and leave it alone.

[bwringer]

Figure out where the leaks are coming from, fix it, and ride another 100,000 miles.

No, you don't need to rebuild it unless something went bad wrong. The 850 engine is pretty easy on its bores, and will easily go 150,000 miles or more before any bore work is needed.

For example, a common leak is oil coming from the Mystery Hole -- this is usually just the o-ring on the nose of the starter, about $2 and maybe 20 minutes of work. The cam chain tensioner often leaks as well -- this involves less than $10 in parts and an hour or so of your time:

http://bwringer.com/gs/camchaintens.html

The o-ring around the gear position indicator switch also is a common leak and is dead easy to fix.

Or the tach cable seal -- happens to every GS, easy and cheap fix:

http://bwringer.com/gs/tachcableseals.html

The crank seal, stator cover gasket, valve cover gasket, or clutch cover gasket are also not difficult or expensive projects. If needed, you can even replace the valve stem seals without removing the head.


Yes, a leaking base gasket or head gasket will cost a few more bucks to do right, but is still probably less than most car payments...



In case you're wondering, this is what I mean by the mystery hole -- it's a drain for the starter cavity, and a common source of fear and panic amongst new GS owners:

[Rob S.]

I wouldn't mess with it unless your compression numbers are low.

Maybe I'll just keep cleaning it off and leave it alone.

That's the ticket!

[wymple]

That mystery hole seems to be about where my tiny leaks are originating from. All my symptoms are only on the stator side of the engine as well.

[chuck hahn]

May be the starter motor oring failing.

[tkent02]

Figure out where the leaks are coming from, fix it, and ride another 100,000 miles.

What he said. 850s last forever, most leaks are easy to fix, so unless you really want the 1100 engine in there it's a no brainer.

[chef1366]

May be the starter motor oring failing.

This is common and often overlooked.
Good call Chuck.