Seized engine help??

[Natrik]

I just picked up a CA77 305 Dream (year unknown) out of a barn. It is all there, but the engine is seized. I've read online that it's fairly common for these motors to form a "rust seal" in the cylinders after sitting for a very long time. Has anyone come across this? Is there any tricks to freeing up the motor?
I pulled the plugs, (it seems one of the cylinders had some oil in it) and put a whole bunch of PB Blaster penetrating oil in. I tapped, waited for a couple hours, tried the kickstarter and starter again, but it's not budging. I really don't want to have to break the cam chain, seat the valves, make a grease fitting out of a plug and use a grease gun if there's a better way.

It was sitting in neutral because it rolls just fine. The shifter moves up and down but doesn't seem to engage a gear, if that is at all helpful...

I'm really hoping to be able to rebuild the top end without having to crack the cases and do the bottom end if at all possible. Wishful thinking, I guess...

[jensen]

Hi Natrik,

First of all, welcome to this forum, this is the best place to be when having a CA77.

Penetrating oil needs time to penetrate, the more it is rusted, the more time it needs.
I had the same problem with a CB72 '62, found in a chicken barn, it took four weeks to free it gently.

Squirt in the PB blaster every day, tab a little, and wait for the next day.
Start soaking all bolts and nuts on the engine with PB blaster, soak them everyday.

See it as a game of chess, keep thinking and eventually you will win, if you want to win too fast, you'll lose. If you lose your crank, you have to strip everything, also your wallet.

You cant undo what formed in 30 or 40 years in a couple of hours.

Jensen

[rustywrench]

Natrik,
I strongly recommend you use the search button in the task bar on the left of your main page screen. There you will find many posts for this subject. Jensen makes a good point that it does take a lot of time to free these things. Hopefully yours will let go willingly and not give you much grief.
A Bill Silvers guide to restoration would be a great investment and give you some tips in this as well.

The trany most likely will not be an issue but I would at the very least pull the side cover and make sure the clutch plates are not stuck together. Post pics and keep us informed of your progress. Welcome to our world, RW

[ilikevelos]

Last fall I put a cb77 on hte road that was last registered in 1967 and had rust completely though the entire bottom on the tank. It was seized, probably badly. I put a dropper full of kroil in each cylinder about once a week for about 6 weeks. After a few weeks, I bumped the engine with the rear wheel in top gear (this gives the best leverage) each week. Take the spark plugs out for this. After about 6 weeks, the rings let loose with a bang and the bike shot kroil out of both spark plugs about 6 feet. Dont use the kick starter for this as it is somewhat delicate on a superhawk.

I had to replace several seals, and a number of parts including the tank, but the engine started once I checked the valves, timing and cleaned the carbureators. I rode it gently for about 100 miles and then started riding it harder. I have about 200 mi on it now but it seems to run well and the head has never been off.

[Natrik]

I put P'Blaster in the plug holes every day for about four weeks, and wiggled the crank back and forth with the rotor (bad idea, I ruined the rotor doing this). It didn't go anywhere.

This was my solution: First I cut the cam chain and rotated the cam until the valves on the #2 cylinder were closed. The I hollowed out a spark plug and brazed an air fitting onto it. I took a hydraulic hand pump, filled the cylinder and the pump with ATF fluid, and started pumping. I saw the crank start to move after a few pumps, and after a few more I had it at BDC. I took the heads off, lifted the cylinders up with a 2x4 and used a dowel and mallet to tap the pistons out the rest of the way. I think this motor was seized worse than others, looking at the pistons and cylinders I realize now that penetrating oil wouldn't have done the job. The 4 ton pump did the trick. You can do the same thing with a grease gun, but grease is more expensive and a lot harder to clean up.

Unfortunately, when I was tapping the pistons out, the edges of the cylinder sleeves hit the casing and knocked a chunk out of each. So now I'm looking at about $500 in parts to get the top end completely rebuilt, but when I'm finished I'll have more or less a brand new engine. The bottom end was immaculate, and the engine only has 7,999 miles on the clock so everything else should be fine. Now I just need to finish up a couple of the other builds in my shop and free up the funds to get it done.....