Seized Motor Best Recipe

[britman]

Ok I admit, maybe I have a problem with old Hondas following me home.  This one from a couple of days ago, 65 CL77, motor frozen tighter than a nat's ear hole.  Inspection camera shows majority of rust in the right cylinder, not the worst I have ever seen, but bad enough.  Currently PB Blaster and Marvel Mystery Oil soaking.  I have heard of diesel and atf, Coke Cola, acetone, vinegar, the combination is almost endless.  Any personal experience here on what has worked for you....

[Muzz]

Wayne Orwig's recipe of ATF/acetone works for me.

That looks like a real barrnfind there Britman!

[LowRyter]

CL77.  Perhaps one of the oldest motorcycle that is viable for modern riding.   

[Huzo]

It looks really “straight”.

[wirespokes]

Better than ATF/Acetone is Power Steering Fluid and Acetone.

Heat the cylinder with a propane torch, then try to turn the engine back and forth. Do that everyday and shouldn't take more than a week.  Don't force it. When it's ready, it'll go easy.

Patience is paramount.

[britman]

A little over two weeks, acetone and ATF, hit with the torch every couple of days, damned it it didn't free up tonight.  In the meantime I found a second engine at a price I just couldn't pass up.  Free, shifts like butter, but low compression.  Two on the bench, I guess I will hold a lottery about who gets the rebuild. I have got to do something, I am out of room. Thanks one and all for the comments.......

[SIR REAL ED]

A little over two weeks, acetone and ATF, hit with the torch every couple of days, damned it it didn't free up tonight.  In the meantime I found a second engine at a price I just couldn't pass up.  Free, shifts like butter, but low compression.  Two on the bench, I guess I will hold a lottery about who gets the rebuild. I have got to do something, I am out of room. Thanks one and all for the comments.......

I love the silver bike with the red frame.  Wow!  Memories.

Recently acquired a free Honda 1985 XR100 and a 1974 Honda trail 90.  The trail 90 has 35,000 miles on it!  Still seems to have plenty of compression.

[cliffrod]

A little over two weeks, acetone and ATF, hit with the torch every couple of days, damned it it didn't free up tonight.  In the meantime I found a second engine at a price I just couldn't pass up.  Free, shifts like butter, but low compression.  Two on the bench, I guess I will hold a lottery about who gets the rebuild. I have got to do something, I am out of room. Thanks one and all for the comments.......

If the engine was seized, the rings may also still be stuck.   Keep it moist with the acetone & atf and see what happens.  If it does run, a few heat cycles may also help the rings come back into proper function.

[harry h]

These pistons are out of a car but same issue.  I tried everything but after 50 years of being seized, my engine builder had to punch out each piston.  Took him 5 hours and we just had to bore 30 over for a new set.

[britman]

I am pretty sure one of them is going to get a total rebuild.  I have examined the oil slingers, clutch plates, and carbon build up on both motors and I think the one with that still shifts through the gears and has the low compression is going to the prom.  It is not the numbers matching motor, but in these early Honda's the frame and engine numbers were nearly always off by up to 30 to 40 numbers anyway.  I am even leaning to have Classic Honda Restoration out of Maryland do the work.  Hits the mad money fund pretty hard, but it is gone over from top to bottom and comes back so damn pretty. It gives me tons of time, to sort out the title and make the frame and other parts match a shiny new looking engine.  I know I can't keep both CL77's , so I will probably sell one.  I will make the call when the time comes, but I really enjoy the process of bringing one back, literary my favorite bike of all time.

[Tom]

Go on to Youtube.  A guy named "Mustie" did a 5 part episode on doing what you want to do to a CB350. 

[SIR REAL ED]

Better than ATF/Acetone is Power Steering Fluid and Acetone.

Heat the cylinder with a propane torch, then try to turn the engine back and forth. Do that everyday and shouldn't take more than a week.  Don't force it. When it's ready, it'll go easy.

Patience is paramount.

Interesting.  I have heard more than once that ATF and Power Steering Fluid are virtually identical.

[Tom]

MMO.   

[Big_Jim59]

Back in the 1970s I was a Triumph mechanic at a dealer in a large Midwestern City. Every spring we would have a couple of Triumph twins show up, locked up from rusting away is a garage with an invented dryer. The moist air would lightly rust and stick the cylinder with an open intake or exhaust valve.

The un-sticking process is pretty simple. 1) Pull the gas tank and pull the rocker covers and take the pressure off the valves so they close. 2) Remove spark plugs. 3) make a tool by breaking the insulator out of a spark plug and attaching an air chuck nipple to it. We just brazed one on. 4) squirt some light oil of your choice into the cylinder. 5) install the tool and put 100 PSI of air on it. 6) You will know when you have success because the piston will swoosh to the bottom audibly. I still have that tool in my tool box 30 years later.

No pulling heads, no banging on pistons, so special mixtures of ATF and Marvel Mystery oil. Just good old air pressure.

On a Honda twin it was be an easy matter to pull the valve cover and the cam.

Jim

[wirespokes]

Interesting.  I have heard more than once that ATF and Power Steering Fluid are virtually identical.

I thought the same thing, but the guy who figured out that PSF (power steering fluid) and Acetone work well together claims there's a difference. Somehow he slipped when promoting the formula and said ATF instead, and that's what stuck. But he says PSF works better.

Jim - how long would it take to free an engine that way?

[Sasquatch Jim]

 some years ago, I had a honda 305 that was sunk under  water.  I put liquid break free oil in the cylinders and left the spark plugs out.  I put it in fourth gear and rocked it back and forth until I finally got the pistons to move then walked it around the parking lot until I could move it without strain.  Then I poured  gas and oil mix into the cylinders and kicked it over squirting the liquid out both holes.  After a severe carb cleaning I put gas in the tank and started it up.  Much smoke for the first few minutes then got it to idle and tuned it up.  It did smoke a little but ran fine for a couple of years before I sold it.  A credit Honda's ability to make an indestructible engine.

[brider]

It did smoke a little but ran fine for a couple of years before I sold it.  A credit Honda's ability to make an indestructible engine.

So in general, with frozen pistons, isn't it usually a VERY BAD thing to un-stick a piston using whatever liquid substance it takes, then begin moving that piston up/down really fast by starting the engine, with that liquified rustiness trapped between the rings and grinding up and down against the cyl walls, without FIRST doing what Jim described: gas/oil in the cyls to clean them out? Even with that method (which I've never heard anyone else mention, just free the pistons up and then run it...), it seems like an instant way to damage the cyls. Wouldn't it ALWAYS be better to pull the cyls off to clean the pistons/rings?

[Tom]

This is the guy I mentioned earlier on the resurrection of a CB350.  About 5 parts total.  The first installment is him acquiring the bike and "unlocking" the engine.  Not as bad as watching paint dry but it does move slow. 

https://www.youtube.com/watch?v=3JDqXVn0T-M&list=PLZJS6Md1UOg3tHE1jjqFuPj4_OOs9w7Pq

[joe-dean]

what we used to do at the honda dealer I worked at during the seventies penetrating oil in the cyclinders.
then shift bike up to top gear 4th or 5th depending on model. push bike forward and backwards it may take several days
but will brake loose.
I did that on a ducati 860gt I got a couple of years ago that took me about two weeks of jerking that bike back and forth till it broke
loose give it a try remember top gear

[hauto]

Bought this at a yard sale.Don't know who made it,but it the best penetrating oil I ever used.It has unfrozen things that other could not even come close to. I'll buy a 55 gal drum if I could find one of it

[SIR REAL ED]

Back in the 1970s I was a Triumph mechanic at a dealer in a large Midwestern City. Every spring we would have a couple of Triumph twins show up, locked up from rusting away is a garage with an invented dryer. The moist air would lightly rust and stick the cylinder with an open intake or exhaust valve.

The un-sticking process is pretty simple. 1) Pull the gas tank and pull the rocker covers and take the pressure off the valves so they close. 2) Remove spark plugs. 3) make a tool by breaking the insulator out of a spark plug and attaching an air chuck nipple to it. We just brazed one on. 4) squirt some light oil of your choice into the cylinder. 5) install the tool and put 100 PSI of air on it. 6) You will know when you have success because the piston will swoosh to the bottom audibly. I still have that tool in my tool box 30 years later.

No pulling heads, no banging on pistons, so special mixtures of ATF and Marvel Mystery oil. Just good old air pressure.

On a Honda twin it was be an easy matter to pull the valve cover and the cam.

Jim

Excellent trick for a mildly stuck engine.  Thanks, I always love these old farmer/mechanic tips. 

"Take old Bill over there.  He's forgotten more about welding/fixing bikes/etc. than most people ever knew."

No doubt air pressure after adding one's favorite penetrant of one's choice would be a good way to accelerate the penetration of the liquid past the rings in a seriously stuck engine.