So I'm trying to split the cases in my efforts to remove some stuck pistons in my 1964 CA77; my reasoning here is that I can take apart the connecting rods and lift the pistons and cylinder head free of the crankshaft, and then use Whatever Means Necessary to push, press, pound or otherwise free the pistons from the cylinder head -
I have all the screws and bolts removed from the underside, but it won't come apart. I think it's just age (on the bike :), but am I missing something somewhere? Is there a certain way to do it? I've tapped all around it with a rubber mallet to try to free it up, but no good. It should just lift off and expose the guts of the motor, right? Is there a 'pry-point' that helps crack the case open?
(2) How do you get the chain off from around the clutch base and crank shaft? The book says to pull off the clutch basket, chain and crankshaft sprocket by hand, keeping the assembly parallel to the case, and the clutch basket slides easy enough, but the shaft sprocket is not sliding with it; it looks like there's a big nut with 4 shallow, square notches around it on the end of the cranksgaft, held in place by retaining tabs, which seems to keep the assembly from sliding off. The clutch chain goes around a sprocket there. It looks a lot like the clutch nut from my '78 CX500; do I just bend back the tabs and apply a drift to the 4-notched nut? Or do I have to break the chain, slide off the basket and go to work on the crankshaft sprocket?
(3) On the face of the metal plate on the rotor (the plate that has the timing marks on it) is stamped C72; my engine block has CA77E stamped in the aluminum next to the oil filler hole; CA78 is stamped on the frame - I wonder if somebody has changed out the rotor...??
This is my first real foray into an engine; any advice is most welcome...
-John
Splitting The Cases ??
case splittingJohn,
Don't be two concerned about what the rotor has on it at this time. You have bigger fish to fry. As a matter of fact my Cl's have CB72l on them and they are cl77 engines. Once you have checked the two nuts in the valley on top, you can separate the two halves and for this I use an old army knife blade in the joints. It's just enough to apply separation and not be destructive to the mating surfaces. I hope you are not thinking you can unbolt the rod bolts once exposing the crank. These cranks are pressed together and apart; an operation still above my head and better addressed by the bigger guns around here. It sure would be nice if they made these things with rod caps to pull the crank and leave pistons where they are. If the crank can be separated while still in the crankcase I'd be quite surprised. Now let's get that clutch off. First move the locking tabs from the nut. Make sure you get them all cuz sometimes there are more than one tab. (don't ask how I know). Now with a blunt chisel or drift, push nut ccw and remove. Nut,lock washer, washer, oil spinner drive gear. Now remove the four bolts and spring from the clutch. Under the pressure plate you will find a snap ring and remove it. Now the clutch,chain and drive gear will come off as a package. I sure hope you have good luck with those pistons. They're giving you a bad case of mission impossible. RW
Splitting the CasesThanks for the replies, guys -
Donzie, yes, I saw those; those are off; I'll try tapping on those two bolts... Rusty - I like the army knife trick; I have one, and I'll try it. "I hope you are not thinking you can unbolt the rod bolts once exposing the crank. These cranks are pressed together and apart." Yes, that's what I was thinking; and Yes, I wondered ( and kind of figured) that they'd be pressed on...(ask me about Fiat water pumps sometime...),and yes, it WOULD be nice if engineers thought about future repairs, but obviously that's not the case here... What I've done so far, after struggling with the cases and being defeated, is I went back to the pistons, which have been soaking in PB Blaster for about two weeks, and managed to get a shim in and around the piston heads, cleaning out all the crap that was in the tiny space between the cylinder wall and piston crown. One piston, I managed to be able to get the shim to go all the way around without resistance, at a depth of about 3/8ths of an inch; the other piston I have two areas in that same path around the crown that are so tight against the crown the shim won't pass through those areas. I wound up filling the piston crown areas with PB last night and just letting it sit again. I believe the resistance I can feel with the shim at the bottom of it's 3/8th in depth is the oil ring, although I don't know for sure; and I don't know if I can get anything past it to allow penetrant to soak into those areas to help loosen things up; MAYBE some heat would help, (I've tried), but where do I apply it, for how long, and what/how do I go about dislodging/moving the pistons when I do? I have a rubber mallet and a length of wood I've been tapping on the pistons with, not too hard but aggressively enough that I think it should break any rust-bond in there....and I don't know for sure, but I also have a sneaking suspicion the pistons are at BDC: the piston crowns are level with the top of the cylinder head, leaving me enough room to allow for a pool of liquid around the piston crown, but it doesn't look like there's any room for them to move further down - The pistons, when I rotate them, WILL lift enough to allow about a half-inch of space between the block and cylinder head, and I have tried shimming it up and whacking the piston heads, but to no avail; plus I'm worried about what that shock is doing to my bearings and connector rods, so I've done so gently, but not TOO gently... And (3), all this being equal, do I have to remove the clutch and drive sprocket if I'm going to open the cases? It doesn't LOOK like anything will get in the way, but does the clutch and sprocket assy have to come off to open the cases? If not, that's great! I'm a firm believer in the KISS (Keep It Simple, Stupid) principle... SO, given all of the above, with the main goal being to free the pistons, what can I do? Or am I effectively screwed and need a new engine? I DO have a bearing puller and I was thinking of trying to rig up a way to push one piston down at a time, but wouldn't I need to apply equal pressure to BOTH pistons for that to work? I guess using a 20-lb sledge and a Paul Bunyan swing is probably a bit much, too, but I'm almost there... What do you think? Has anybody else had this same problem, and if so, how'd they solve it? -John
No, I don't see any; the seams seem really clean...although there IS some kind of petrified goo on the Outside of the engine, on the block...looks like dried amber where something was attached to the block at the top of the engine 'valley', but broke off; almost like somebody tried to reattach something there, but it didn't take. It doe not appear to penetrate the case...a pic would explain it better, but I don't have one..
put a block of wood on the 2 top side studs and give it a good few whacks. use wood and a mini sledge over anything sharp and metal to separate those cases.
I can't remember from when i did it, but I think you need that rotor ( and starter sprocket) off before you separate the cases... g good time to check starter clutch rollers and springs.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||