Topic: Seized Motor

[kmart550]

Good day all.  So the other day while driving home from work my motor seized on my '77 550F.  So I put some Kroil and other fulids in the cylinders to try and free the motor.  I then took a large breaker bar and 14mm socket to the crank a few days later and was able to free the motor.  So I put the plugs back in, changed the oil, filter and tried to start the bike.  The motor turns but it doesn't even seem to try and start i.e all it seems like the starter and crank are turning but nothing else is happening.  It has compression and spark also which is the confusing part.  

So is there something else internally that could be wrong here?  

Hope I explained well enough.

--Kyle

[TwoTired]

Have you tried new spark plugs?  I think there is graphite in Kroil.  This will bridge/short the spark plugs so the spark can't jump the gap.

[Bodi]

x

[kmart550]

Have you tried new spark plugs?  I think there is graphite in Kroil.  This will bridge/short the spark plugs so the spark can't jump the gap.

Come to think of it when I first tried to start it I blew a fuse but I had a battery charger on it and thought that may have had something to do with it.  I'll give it a shot...thanks. 

[kmart550]

Tried new spark plugs but same results.  A question I have is could the timing have gotten thrown off from the engine seizing?  Any other possibilities?  I'm sure I'm just delaying the inevitable which is tearing the motor apart but I figured I would try as much as I can before I tear into it.  Any help is much appreciated!!


--Kyle

[OldSchool_IsCool]

You can check you ignition timing with a light bulb on gator clips.  One clip to the engine block and the other to the blue wire on the points (assuming stock ignition).  With the key on, kill switch on, good battery and no wiring faults, the light should turn off just as the F mark of 1.4 aligns with the case pointer.  Standard static timing procedure as detailed in your repair manual.

To check cam timing, you may need to pop the cam cover off (can be done with motor in frame).  Check that the T1.4 mark aligns with the case pointer as the notch in the right end of the cam shaft aligns with the flat of the head (i.e points to the 3 o'clock OR 9 o'clock position).

[Spanner 1]

Hope you didn't put that breaker bar on the points end of the crank... if so then the points shaft is prolly bent/ twisted, maybe?.. that would mess-up the point gap/timing. It's only a skinny little shaft threaded into the crankshaft end and only tasked with turning the points cam and not for crank turning duty with a wrench/bar.

[kmart550]

Well I at first tried it on the points end (put minimal pressure on it) but then turned it on the other side (left side of the bike).  So i'm guessing I may have moved the shaft slightly but I do not think i bent/twisted anything.  So if it were to have moved how would I ''reset" that? 


--Kyle

[Spanner 1]

Probably O.K. then on the points side.... the locating pin behind the advance unit would have to shear for the T mark to be off...

[TwoTired]

You need three things for the engine to run. Compression, spark, and air fuel mixture in the correct ratio/range.

Have you checked for spark at the spark plug (seeing it arc across the electrodes)?

Is the fuel on, the level high, or the tap on reserve?

Did you do a compression check?

[kmart550]

You need three things for the engine to run. Compression, spark, and air fuel mixture in the correct ratio/range.

Have you checked for spark at the spark plug (seeing it arc across the electrodes)?

Is the fuel on, the level high, or the tap on reserve?

Did you do a compression check?

I've checked for spark, which I have.  Fuel is on and good.  As for compression the tester I have doesn't have the right diameter to thread in but just by turning it over with the plugs out and a finger over the hole I can feel a good amount of pressure so i'm assuming there is enought compression to at least turn it over.  That makes me believe the timing is somewhat messed up.  Tonight I plan on setting the timing again and see what happens. 

[kmart550]

Took the caps off of the valve cover for adjusting the valves, turned the bike over and none of the valves turned.  So i'm guessing when it ceized up the chain inside broke.  Going to pull the engine tonight and see what I can find out.  Thanks for the previous posts for ideas. 

--Kyle

[dusterdude]

how bout stuck rings and therefore no compression

[OldSchool_IsCool]

You can do top end work on a 550 with the engine in the frame.  Just so ya know.

[kmart550]

how bout stuck rings and therefore no compression

Possibly but the motor now turns over and with the plugs out and a finger over the spark plug hole I can feal strong pressure. (I know its not a good way to test for compression.)

You can do top end work on a 550 with the engine in the frame.  Just so ya know.

Possibly but the motor now turns over and with the plugs out and a finger over the spark plug hole I can feal strong pressure. (I know its not a good way to test for compression.)

I know I can do top end work with the motor in the frame but since the motor was seized and i'm going to be opening it up I figure i'll check rings and cylinder walls.  

But at any rate I got the motor out tonight and plan on opening it up tomorrow.  Thanks again for the suggestions guys.  
--Kyle

[dave500]

hey fellas,,seized engine here!what caused this?dont just press on and try and start and keep going,,are you sure it had seized and not just spark error or some other thing?worst case is oil pump dead,it took a breaker bar to free up this engine??,,hey,,its knackered,maybe?dont ever force an engine in this condition,if you cant operate the kick starter by hand with the plugs out theres something bad going on,,dont fkcen force it over.

[kmart550]

hey fellas,,seized engine here!what caused this?dont just press on and try and start and keep going,,are you sure it had seized and not just spark error or some other thing?worst case is oil pump dead,it took a breaker bar to free up this engine??,,hey,,its knackered,maybe?dont ever force an engine in this condition,if you cant operate the kick starter by hand with the plugs out theres something bad going on,,dont fkcen force it over.

Couldn't really understand that post sorry.  But anyways got the valve cover off.  The 2 bolts that hold the plate from the cam onto the cam chain were broken off.  There was 1 present that was pretty mangled and the other was missing.  There really wasn't any debris by the cam but I'll be taking the head off and finding out. 

The question I have is it possible the bolts just loosend and caused it to seem as though the engine seized or could the engine have seized causing the 2 bolts to break? 

Thanks
--Kyle

[scottly]

The question I have is it possible the bolts just loosend and caused it to seem as though the engine seized or could the engine have seized causing the 2 bolts to break? 

Thanks
--Kyle

It's also possible that the cam itself seized, and the bolts sheared off. Check the cam journals before you pull the head.

[Fritz]

The question I have is it possible the bolts just loosend and caused it to seem as though the engine seized or could the engine have seized causing the 2 bolts to break?  

A seized piston would not cause the bolts to break. But a seized camshaft could.
My wild guess: The bolts became loose because they haven't been torqued correctly/were missing locktite (there are several reports on this forum describing the same problem).
The bolts sheered off and the camshaft stopped rotating -> Pistons hit valves and valves bent. By 'breaking loose' your engine, maybe you did even more damage. You'll know when you take off the head.
So I think that you will either have to have your head repaired (new valve guides, valve seats ground, new valves -> quite expensive) or buy a good used head (much cheaper).

But: You'll have to open the engine in order to inspect the damage. And as you may have used a lot of force on the bolt that holds the spark advancer, I'd take it off and make sure that it's still straight. Also take the advancer out and inspect the dowel pin that connects it to the crankshaft. It may have taken some damage too.