Topic: Engine seized... From sitting only 2 weeks?!?

[BARKER]

Hi guys,

I recently picked up a 78' cb550k that had not been started in a very long time (no idea how long, but the last time it was on the road was in 1983!). A couple of weeks ago I turned it over by hand, no issues. I also turned it over via the electric start with no issues (it never ran as it had no spark). Then... I walked away from it for two weeks.

Now...

SEIZED. How could this even happen?

I've got some ATF/acetone down the cylinders, but this all seems very bizarre.

Are there any other culprits that I should be looking for?

[jgger]

If it sat that long and you electric kicked it, that would be a very dry start. After an oil change on a running bike or a motor rebuild there is residual oil or assembly lube on the moving parts. Not so in your case. I hope you didn't  gall any bearings. If you are lucky it is just goo in the cylinders and it will break free with the atf/acetone.  Just my $0.02 hope I'm wrong.

[BARKER]

Yeah, that's why I turned it over by hand first to see if it was seized at all. Like I said... I'm not sure how long it actually sat. I guess a year down will be in order if the ATF/acetone doesn't work anything free. 

[spotty]

have you tried rocking it back and forth in gear to see if it frees up, the extra momentum of the weight of the bike might make a difference ? is it stuck in kick and elec modes ?

[BARKER]

have you tried rocking it back and forth in gear to see if it frees up, the extra momentum of the weight of the bike might make a difference ? is it stuck in kick and elec modes ?

Bike doesn't have a chain at the moment (bought for $200... It was missing a few things). So no rocking...yet.

It will not kick over in any gear. Electric won't do it either. With the clutch lever pulled, the kicker spins freely.

[spotty]

ah well , that me out then

at least if it changes gear then its only the top end thats stuck instead of something randomly letting go in the box after its previous turnings over

good luck

maybe pull the rocker inspection caps ( do 550's have them or can you get the rocker box off) and make sure all the valves are still in their places and none have dropped into the cylinders ? not trying to alarm you but if its easy to do then it can't hurt to find out and could save any further damage ?

another thought is try turning the motor gently using the big nut inside the points cover, that way you can see if it turns the wrong way at least

[Don R]

 Did you put acetone in it and put the plugs back in? If so, it's hydro locked and continuing to turn it will bend the rings or rods. 

[BARKER]

Did you put acetone in it and put the plugs back in? If so, it's hydro locked and continuing to turn it will bend the rings or rods.

No. I put the mix in AFTER the seizure happened (just yesterday). I have not attempted to turn it yet. Planning to pull the plugs and then try turning it.

[seanbarney41]

Make sure valve/s are not stuck open before trying to turn it any further.

[1976cb750f836]

I would try turning it backwards, by hand, the first time after soak. In case something is lodged  between piston top and head.

[Don R]

That is bizarre.  Keep us informed what you find.

[BARKER]

Make sure valve/s are not stuck open before trying to turn it any further.

Will do. Honestly, I haven't had this happen before. Do you just pull the tappet covers for inspection? Or pull the exhaust and intake/carbs?

[BARKER]

I would try turning it backwards, by hand, the first time after soak. In case something is lodged  between piston top and head.

Will do. I remember when I first detected the seize, that I tried going both directions and it would not budge.

Current plan is to hit the garage in 5 mins, pull off the tappet covers (and maybe a few other things) and remove the plugs to see if I can find the culprit. If it looks all clear, then I might try some pressure on the 14mm bolt under the rotor on the left side of the engine.

Something isn't right about all this though... it could not have spun long enough (by hand or starter) to have galled bearings or gotten anything hot. It should rotate the opposite direction if a valve was stuck... but doesn't. It's like something is mechanically binding...

[Don R]

  I took one apart that had sat that long and was amazed how well oiled things were even though the PO had left the carbs off and it sat in a barn collecting mouse nests in the ports and cylinders. I also got a bike left leaning against a clothes line pole outside for years with the carbs off but the intakes were stuffed with plastic grocery bags. There was moss on the rocker cover, and it's running to this day. You just never know. Good Luck.

[BARKER]

Some extra info as of 5 minutes ago.

- it's stuck exactly halfway between the fire 1 -4 and the fire 2-3 positions

- exhaust valves are loose on cylinders 1+3. Intake is loose on 2+4. All others do not wiggle.

- I believe I can see the #1 intake valve.

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[seanbarney41]

Alls i can think of is back off the adjuster and make sure the valve follows the adjuster...on the valves that are open.  If one doesn't follow the adjuster, that's the stuck one.

[BARKER]

It's freeeeee! I lightly put pressure on the opposite direction of engine rotation using the 14mm nut under the rotor. And it moved a little way with ease. A couple of light presses back and forth and it is right as rain again.

I'd still like to know what caused this... It's a $200 motorcycle... It'll probably end up getting torn down eventually due to whatever caused this problem! Borrowed time me thinks.

the mix of ATF and acetone seemed to do the trick but boy howdy did it ever make a mess on my floor!



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[1976cb750f836]

I'd still like to know what caused this... It's a $200 motorcycle... It'll probably end up getting torn down eventually due to whatever caused this problem! Borrowed time me thinks.

I'm betting rust on cylinder walls? When u turned it over the first time, u wedged the piston into the rust, then over time the atf mix, melted the rust enough to free up. Happened to me more than once, then upon teardown, find nothing but rusty cylinder walls.
Fire that thing up after setting all major tune up specs. Add some 2stroke oil, or marvel mystery oil to gas (helps free stuck rings), might smoke, might not?

[BARKER]

I'd still like to know what caused this... It's a $200 motorcycle... It'll probably end up getting torn down eventually due to whatever caused this problem! Borrowed time me thinks.

I'm betting rust on cylinder walls? When u turned it over the first time, u wedged the piston into the rust, then over time the atf mix, melted the rust enough to free up. Happened to me more than once, then upon teardown, find nothing but rusty cylinder walls.
Fire that thing up after setting all major tune up specs. Add some 2stroke oil, or marvel mystery oil to gas (helps free stuck rings), might smoke, might not?

Those are my thoughts exactly! Borrowed time. But figuring out this stuff is what I love about bikes and cars. Frustrating but incredibly rewarding. Often I find myself enjoying working on them MORE than actually riding them.

[1976cb750f836]

I love to tinker also. Ill try anything mechanical . A toaster, a colt 45, car, bike, anything not computer controlled.
U might be surprised on borrowed time. If it still has original cast iron rings, they will cut the rust away and reseat sometimes. If theirs pitting, you'll have a smoker?