Connecting Rod frozen at crankshaft... Any way to un-freeze or remove w/o splitting

[Dave_A]

1981 450L. Bought non-running

Right-hand connecting rod is frozen at the crankshaft, with piston at/around top-dead-center

Left hand piston is OK.

No signs of scoring or damage to the cylinders, pistons, or cam journals. Cyls look freshly honed, etc... Bike was rather low on oil (1-2qts), but yet didn't seem to show any signs of low-oil use other than this one frozen rod....

I have a set of connecting rods OTW from E-bay (even though I only need one), but (a) would like to see if there is any way to 'revive' this one before they get there, AND if not, if there is any way to get it out of the engine (and get it replaced) WITHOUT splitting cases...

Seller says he had this problem after his chain came loose & busted his clutch pushrod (which he fixed) so I am assuming that either: (A) it's frozen from sitting (doubt this) or (B) his running it low on oil (running with no valve cover gasket and no RTV, specifically) somehow froze that one rod without visibly impacting all the other parts much 'higher' on the oil circuit....

[Clone]

Is that a plain bearing crank? If it is and the rod is seized, it is corroded beyond a simple fix, you can try soaking it in a mixture of diesel and engine oil or transmission oil and engine oil, then slowly working it back and forth until it loosens up. I would suggest that you take it apart and put in new bearings and polish the crank.

[chef1366]

How do you know that's what is if the motor is frozen?
No disrespect. Just wondering.
I'd rip the motor apart and get a new crank if that's what it is. Those cranks are a dime a dozen.

[rapidray]

No matter what, you have to split the cases to change the rod & clean up the crank. PERIOD! Ray.

[bwringer]

Sounds like it's seized. The crank and rod are junk.

Perhaps you can find another engine, and either transplant the engine or at least the bottom end.

[chef1366]

Sounds like it's seized. The crank and rod are junk.

Perhaps you can find another engine, and either transplant the engine or at least the bottom end.

I didn't even think about that. Those engines are a dime a dozen. They were all about the same from 1980-86. They will all bolt up.

[Dave_A]

How do you know that's what is if the motor is frozen?
No disrespect. Just wondering.
I'd rip the motor apart and get a new crank if that's what it is. Those cranks are a dime a dozen.

I tore down the top-end of the engine after bringing it home...

Right now, it's sitting with the cyls off, and while the left-hand piston wiggles forward and back freely (as it should), the right hand connecting rod (the one that was at TDC) is frozen solid, and will not rotate about the crankshaft.

This is a low-budget project, so I am trying to get it running ASAP, not do a complete lower end tear down and overhaul....

[rudy]

Whatever is holding your bearing will likely destroy it after running a short while if you ever do get it loose. Rust or seizure, either way isn't good. Take the advice of the folks here now, or later when things go wrong, it's up to you. Budget builds often end up costing more than expected, so I hope you didn't spend much on buying that bike since you knew of the problems beforehand.

[rapidray]

I tore down the top-end of the engine after bringing it home...

Right now, it's sitting with the cyls off, and while the left-hand piston wiggles forward and back freely (as it should), the right hand connecting rod (the one that was at TDC) is frozen solid, and will not rotate about the crankshaft.

This is a low-budget project, so I am trying to get it running ASAP, not do a complete lower end tear down and overhaul....

LISTEN! Many, I repeat MANY of us on here & are Suzuki mechanics & if you don't want our advice, STOP asking. To fix that motor you HAVE to split the cases! Either take it apart & fix it or stop wasting our time! Ray.

[bwringer]

Here's the crank from a GS500 engine with a seized rod bearing.

Sorry the focus is a little off, but you can see that the horrible remains of the bearing shell are smeared all over the place, and the crank is badly gouged.

You're looking at a hunk of scrap metal. This is very similar to what yours looks like:




Al bought this GS500 cheap complete with two seized engines. We tracked down a good used crankshaft and assembled one good engine from the best of both.

Here's the rebuild photo gallery if you'd like a peek inside:

http://pix.bwringer.com/v/bwringer/gs500_engine/

[SqDancerLynn1]

With the top end off It won't take more than 2 hours to remove the engine & split the cases. Otherwise you could end up wasting a lot of time & $$$$. If you insist You could try spraying some PB Blaster around the lower end. Work it back & forth

[Dave_A]

With the top end off It won't take more than 2 hours to remove the engine & split the cases. Otherwise you could end up wasting a lot of time & $$$$. If you insist You could try spraying some PB Blaster around the lower end. Work it back & forth

PB worked...

It's still stiff, but it's moving now...

I looked at the crank as it turned, it didn't look chewed up like the one in the posted photo...

In any case, IF I can get it to release the rest of the way, then if/when it fails for good, I'll just buy a replacement engine off e-bay...

[Jon Burke]

PB worked...

It's still stiff, but it's moving now...

I looked at the crank as it turned, it didn't look chewed up like the one in the posted photo...

In any case, IF I can get it to release the rest of the way, then if/when it fails for good, I'll just buy a replacement engine off e-bay...

Won't take very long if there was enough corrosion to seize the rod to the crankshft. The rust and crud will finish the rod bearing and crank bearing off in no time. Wouldn't ride very far from home. Maybe better use the rear passenger pegs too when she decides to make a window through the bock.

[Nessism]

PB worked...

It's still stiff, but it's moving now...

I looked at the crank as it turned, it didn't look chewed up like the one in the posted photo...

In any case, IF I can get it to release the rest of the way, then if/when it fails for good, I'll just buy a replacement engine off e-bay...

Right after high school I had a Triumph TR-4A (car). Engine seized one day due to lack of coolant - my fault. Pulled off the head and removed the pistons only to find one cracked and the oil ring groove crushed down pinching the ring- the engine was pumping out massive amounts of blue smoke because the oil ring wasn't doing it's job. Took a file to the piston and opened up the ring groove and installed new rings. Slammed that bad boy together and it actually ran. Sold it two weeks later.

Using PB Blaster to free a stuck rod is almost as bad a hack job as I did. You should be ashamed...I was.

BTW, the guy that bought the Triumph offered me a "Lid" of marijuana for the car. Can't remember how much that was worth but I declined and asked for cash, which he paid. Never heard from him again...thank god.

.

[chef1366]

Putting that engine together like that will be a colossal waste of time.
Could be dangerous when the crank freezes again.