Motor seized up... Then released?!?!

[jrubek]

Hey folks,

Ok, I got the brake thing worked out. They are not perfect but they do work and are road worthy. I registered the bike today and took it for it's first open highway run... Yea, I had to walk it back home.

I'm going to start off by saying that I know the carbs are gunked up and it is REALLY hurting performance. I was hoping that running new gas through the carbs would get it running better. I hopped on the freeway (55 mph, 85 degrees) and went about 8 miles. When I took the freeway exit, I heard a lot clanking and some squealing as though it were out of oil. (BTW it does leak a lot of oil out the left side somewhere.) I stopped in a parking lot and bought some oil. I topped it with 1/4 quart of oil then dropped it when I brought it off the center stand. (Figures!)

On the ride back, I didn't hear anything above the wind noise but I couldn't get it to do over 50. When I took my home exit, I pulled in the clutch to downshift and it stalled. This happens with the funky carbs so I figured I would just drop it to 4th and pop start it. (still doing 45 mph here). It felt like I jammed on the brakes. I immediately pulled in the clutch, (now doing 20) I popped it down to third and tried pop starting again and the rear tire locked. I knew I was in trouble there.

I pulled to the side of the road and tried using the starter. The starter clicked hard but the motor didn't turn over at all. I walked the bike home 3/4ths of a mile. Several hours later, I tried it again and it fired up just fine. No problems at all... AAARGHHH!

Ok. I haven't checked the oil level again yet but I'm betting it is ok. My first thought for diagnosing this is to get a reading on the oil pressure. I just don't know how to do that. Do you folks have any ideas where I should go from here?

Thanks much

Jeff Goetz
1979 GS850

[SqDancerLynn1]

I would start by removing the cam cover & doing a visual inspection of the valves, Pull the plugs, remove the points cover on the right side Using a 17mm wrench try & turn the motor over. IF it will not turn ? slide the drive shaft boot back & unbolt the shaft try turning again Next I would remove the beveled drive gears Try turning the engine with the wrench again If it still won't turn start looking for another engine. I have a spare one you can have BUT Portland is too far for me

[Jon78gs1000]

Did the engine seem too hot? Kind of sounds like ring seizure. See what the cams and shims look like.
2 stroke bikes can get it if they get too hot.Once they cool down they can start right up. In my 1000 manual it shows to put the oil pressure gauge down beside the oil window.
With cam cover off start the bike and make sure that you have oil getting onto the cams.
You could have a pluged oil gallery to the top end,but not sure how you would clean it. Maybe compressed air?

[Tarbash 27]

My friend use to have a yz80 dirtbike that had some pieces of sand in the crankcase. once and a blue moon the motor would lock up and you could take the cylinder of and see a piece of sand in between the crank and case which locked up the motor. so we would turn the engine backwards and the little piece would fall out of place and there you go, it ran again. something is probably getting hung up when the motor is hot and that shrinking when it cools off a bit.

[Joe Nardy]

Take a good look at the starter drive. I had one lock up once upon a time which caused the very large gear on the end of the crankshaft to drive the very small gear on the starter at engine RPM. It didn't take long to melt the starter into one solid piece, which caused the rear wheel to lock up. I grabbed the clutch and got it off the road. I hit the starter button and nothing happened but it bump-started immediately. I cautiously rode it home and tore it down to find the starter meltdown.

Thanks,
Joe