engine replacement for 1982 GS650GL

[Guest]

My poor 1982 GS650GL has had some problems since I picked it up for $300. But the latest issue is that one of the connecting rod bearings wore down and ruined the connecting rod and crankshaft where the bearing used to be. Instead of buying a used crankshaft and new rod I went with option B. Buy a parts bike and use what I can off it.

In a perfect world I'd be able to just drop the bottom of the engine from the parts bike into mine. But nothing's going to be perfect, I'm sure. I probably won't actually get started on it today as I've got some honey-do's to take care of before the Superbowl. But I may at least have time to spray all the bolts down with liquid wrench and drain the engine of any oil. We'll see.

I'll update you all on my progress. And as always, thanks for any and all advice.

Here's the bike I'm fixing up (though as of now its engine is off the bike and in pieces on my workbench).



And here's the parts bike I picked up yesterday.

[barnbiketom]

Why not see if the new engine runs good? save time /money/exasperation?
if it does, plant it on the other bike or swap whatever parts needed for one good bike.
Personally I never open up a motor especially if it's a virgin unless no options.

[tom203]

Wow, look at those handlebars on the parts bike- the guy must have ridden it with arms crossed!
i agree with barnbiketom- why not spend a little time and see how the parts bike engine runs.(put your good carbs on it)With any luck, it might have escaped disaster and you can just swap it in. You could always pull the pan off to get a better idea of the internals.

[habsdoc]

Hey, now you can put some propper exhausts on your build.

[William Groebe]

Ok.

So I finally got some time to do some work on the bike yesterday. I'm wary of just dropping the parts engine on my bike as it's been sitting out in the rain for god knows how long. There's quite a bit of weathering as you can see. Also the signal generator cover was not fully closed, so I'm not sure what damage the elements would do to that. And a bunch of crusty little pieces of who-knows-what fell down into the case when I removed the cylinders.

At this point the engine is off the bike with the top end removed. (I find it easier to remove the engine with the top end off) Since I'm already here with the engine off the bike, and I don't know any history on why the bike wasn't running, I'm tempted to split the cases and check everything out. I'll start with just removing the oil pan first to get a look that way, and clean the oil filter, then I'll listen to what the people on the forum have to say.

Here are some pics to see what I did on Sunday.


Here's a pic of the signal generator cover left open to the elements.




The inside doesn't look terrible, though one of the screws is pretty stripped. I could remove the signal generator and advance governor and replace them with the ones from my original bike.




I'm planning on cleaning up the exhaust and installing it on my bike. No more weird pipes.




Weird rusty oil? Otherwise it looks pretty good inside. I forgot to take valve clearance measurements before pulling out the camshafts.

[William Groebe]

More pics from yesterday's work.

I'm probably going to take the generator cover off so I can rotate the crankshaft and make sure it spins fine. And I haven't checked the play on the connecting rods yet either. I'll do that tonight. I'll be taking off the oil pan to get a look inside and while I'm in there I'll clean out the oil filter. If anyone has any other advice, I'm all ears. This isn't my first trip down this rabbit hole, but any help is always appreciated.




gross.





Starter has seen better days. There was no cover over it, so it was just sitting there rusting.




Look at all that under the starter engine. That's nasty.



Here I am ready to kick the bike over and pull out the engine.

[William Groebe]

argh. Bad news. I pulled on the pistons to check their play and #1 connecting rod has play up and down. Just like the #4 had on my original bike. Probably means a blown bearing and may mean a ruined crankshaft. The whole point of buying this bike was to replace my crankshaft. Talk about bad luck.

I'm going to go ahead and split the cases and check out the damage to the shaft. It would be a miracle if the crank is still good and I can replace the bearing, put a rod in from my original bike and get this thing running this weekend. I'm guessing I'm going to be seriously disappointed.

[tom203]

What a drag! Split cases and hope for miracle.

[William Groebe]

It turns out the donor engine has the exact same problem my original engine had. A worn bearing on a connecting rod which in turn wore a crankshaft journal. I haven't done any measurements on the worn journal, but I did put one of my good rods and bearings on it to test it out and it's loose.

What are the chances of that? The only difference is that the donor engine wore down the #1 rod bearing and mine was worn on #4. Also the #1 piston had no circlip holding the bar in place and the side of the piston is shredded. This engine was in way worse shape than my engine. I'm better off buying a new crankshaft and using my original engine than this zombie mess.

My journey continues.


Here's the worn down bearing and rod.


Here's the worn journal on the shaft.


Here's the banged up piston.


Here's what the inside of this catastrophe looks like.

[tom203]

"What are the chances of that? " I would have bet slim ! Your persistence in the face of these obstacles is extraordinary.
At least the zombie bike appears to have plenty of stuff you could sell to recoup its purchase.
Your pics are fascinating - the trans appears in good shape, what was the mileage on this bike before misfortune showed up?

[William Groebe]

Thanks, tom203.

I haven't removed the transmission yet for inspection, but at first glance it looks fine. I don't know the mileage of the bike as it didn't come with an odometer and was sold as a non-running parts/salvage bike.

There are certainly parts on it I can sell or use, so it's still going to be worth the $100 purchase. It just doesn't help to get mine running. That quest continues.

[barnbiketom]

wow sorry bout the luck. I'm sorry I didn't see the carbs were off it initially.. Not a good sign!
As much as I hate to say it, I, if it were me, would STILL look for another engine. reason is..bottom end, crank bearing and rod bearing stuff is VERY specialized work. requiring perfect selection of bearings with very precise measurments, and the lack of parts and the cost of the parts , with possible re-machining of a crank makes it a no brainer to me. I might be lazy, but there GOTTA BE A BIKE with a motor for like 100-300 bucks.. drop it on and go.
If you find another bike or engine, LOOK closely at the fasteners for buggering. pass on anything but a virgin..theres tons of em around here just sitting with plugged up carbs.
my 2 cents worth but your mileage may vary. and yes your persistance is amazin lol.. don't make your bike "just another orphan" to come up on craigslit in 5 years!!!

[tom203]

In your part of world, I'd probably look for accident victim 650- front end crash, etc. something declared totaled by insurance company and dumped on salvage yard , but with a reasonable chance of decent engine.

[William Groebe]

I'm going to try the replacement crankshaft route for now. I can always swap out a full engine when lightning strikes one day and I find a decent engine nearby. For now I'm going to take your advice from the other day and talk to this guy about buying his crankshaft. http://www.thegsresources.com/_forum...-GS-650L-parts

Anyone know if an '81 crank will swap into an '82 engine?

[tom203]

Sounds good! Ask him for honest opinion on how bearings/rods look- he probably hasn't seen your saga, but most members on here seem honest. Not sure why his upper crankcase got cracked .