Rocker Arm Pin Removal?

[LOUD MOUSE]

I did that once.
Never again as I can cut the chain quickly and each one I have cut were stretched and needed replacement anyway. ......................lm

If you're careful it's possible to release the two halves of the camshaft from the centre sprocket, you need to be careful what position the cams and rockers are in before tapping the cams out.

Once you have released the sprocket from the cams it should drop down far enough to slip the chain off the cam sprocket, lift out the sprocket and then the cylinder head can be removed.

I don't know why I've never suggested this in the case of frozen engines. I know from experience that it can be done as I changed the cam sprocket / advance retard unit on my CL77 a few years ago with the engine in place in the frame.

If you try it this way please let the list know how you get on.

[DJM]

Didn't think my last posting through very well.

The cam shaft halves CAN be removed from the sprocket just as I described but, if the engine is 'frozen,' it's unlikely that the cams and rockers will be in the right position to allow the camshaft halves to be withdrawn.

If they aren't in the right position the 'frozen' engine will of course prevent the engine being turned over to get the cams and rockers lined up for removal.

Just split the chain, it's no big deal. Stuff the area around the cam sprocket with rags or similar, then use a Dremmel with a cut off disc to grind the 'head' off one pin of the cam chain. No need to cut into the chain itself, if you do it carefully the chain could be reused with a secnd split link but I wouldn't recommend it.

Position the Demmel so that the sparks fly away from the engine and not into it, Once you have ground the end of the pin the pin can be driven out of the chain with a long, thin punch and the chain will separate allowing the cylinder head to be removed.

Sorry if my previous posting caused any confusion.

[Dr. Frankenstein]

I got it out with a little effort; I ended up just tapping the camshaft ends out of the chain sprocket - the two end bearings pop right out, and in this case I tapped the right side out first, then kind of back-and-forth'd the other side out of its slot on the cam sprocket.

Once you get the right side out, if you look down the center of the bearing hole you can see a little slot in the cam sprocket that the cam shaft fits into; that slot allows you to get to the Other side of the Left side of the cam shaft, and with a little finesse you can tap it out of the bearing shoulder; just be careful when tapping out the bearings not to put too much strain on the valve rockers themselves. If you do this, you'll see what I mean.

I was then able to rotate the cam sprocket to get to the connector, and got the chain off in one piece.

The problem NOW is how to get the pistons out of their cylinders. Luckily they are at TDC, but they are NOT budging. I've tried heat, lube, more heat, a few (ahem) Gentle taps on the crowns with a block of wood and rubber mallet - I just want to get them moving so I can get them out of there and see how the cylinders look. This bike is going to be a winter project, but I'm just prepping it now. I really want to see why it's locked up; I'm hoping the cylinders aren't trashed.

[DJM]

Actually, having the engine frozen at Top Dead Centre is the worst position to be in!

If you think about it, any force applied to the piston crown will be transmitted down to the vertical connecting rod, effectively trying to push the crank assembly out of the crankcases. This isn't going to happen so likely you will damage the rod, wrist pin or big end assembly.

I realise that your engine is stuck where it is but I think the optimum would be somewhere around 45 degrees before or after TDC.

However you proceed try not to put too much pressure on the piston crown and if you need to go this way try and use a sustained pressure rather than even gentle hammer blows.

Has anyone ever tried splitting the bottom end and trying to pull, or press the crank assembly out of the upper case / cylinders. Since you are pulling on the connecting rods rather than trying to compress them, potentially this is much less likely to result in crank or bearing damage, Just a thought.

[LOUD MOUSE]

Remove the lower case so the crank can hang free.
Now any presure you apply will lower the crank not try to turn it.
What did you see on the piston tops?. ......lm

I got it out with a little effort; I ended up just tapping the camshaft ends out of the chain sprocket - the two end bearings pop right out, and in this case I tapped the right side out first, then kind of back-and-forth'd the other side out of its slot on the cam sprocket.

Once you get the right side out, if you look down the center of the bearing hole you can see a little slot in the cam sprocket that the cam shaft fits into; that slot allows you to get to the Other side of the Left side of the cam shaft, and with a little finesse you can tap it out of the bearing shoulder; just be careful when tapping out the bearings not to put too much strain on the valve rockers themselves. If you do this, you'll see what I mean.

I was then able to rotate the cam sprocket to get to the connector, and got the chain off in one piece.

The problem NOW is how to get the pistons out of their cylinders. Luckily they are at TDC, but they are NOT budging. I've tried heat, lube, more heat, a few (ahem) Gentle taps on the crowns with a block of wood and rubber mallet - I just want to get them moving so I can get them out of there and see how the cylinders look. This bike is going to be a winter project, but I'm just prepping it now. I really want to see why it's locked up; I'm hoping the cylinders aren't trashed.

[Dr. Frankenstein]

Yeah, that's pretty much where I am right now - I tried some more heat, PB Blaster and a few smart pounds with a wooden block and a hammer, and then put it on my 12-ton press and used an old case splitter to apply pressure to both crowns at once, mostly just to see if I could get it to move.

I didn't wale on it - I got too nervous to really crank it down, and yes, I am aware of where those pistons attach, too - but it didn't budge at all, and no scary noises...so I think I'm going to try LoudMouses suggestion and go in through the bottom.

The pistons are "OK" from what I can see - it looks like one of the valve indents is a bit rough on the outside edge, and the valves themselves don't look like they hit anything. But Man, there is NO space around those crowns! I can't even get a thin hammered-out spade I made for a similar project in there, and I mean it's probably .0004. It's Tight!

*I* think somebody put oversize pistons in there and didn't hone or re-do the cylinders, but I'll find out. The rest of the engine is really beautiful inside!

[G-Man]

John

You can't put in o/s pistons without re-boring the cylinders.

You must release the bottom case before hitting those pistons as you will be trasmitting force into the crankshaft, which is the most sensitive and valuable part of your engine.

Try turning the whole thing upside-down and filling the cylinders up with penetrating oil. That might get to the underside of the rings.

Leave it for as long as your patience will allow....

Good luck!

G

Yeah, that's pretty much where I am right now - I tried some more heat, PB Blaster and a few smart pounds with a wooden block and a hammer, and then put it on my 12-ton press and used an old case splitter to apply pressure to both crowns at once, mostly just to see if I could get it to move.

I didn't wale on it - I got too nervous to really crank it down, and yes, I am aware of where those pistons attach, too - but it didn't budge at all, and no scary noises...so I think I'm going to try LoudMouses suggestion and go in through the bottom.

The pistons are "OK" from what I can see - it looks like one of the valve indents is a bit rough on the outside edge, and the valves themselves don't look like they hit anything. But Man, there is NO space around those crowns! I can't even get a thin hammered-out spade I made for a similar project in there, and I mean it's probably .0004. It's Tight!

*I* think somebody put oversize pistons in there and didn't hone or re-do the cylinders, but I'll find out. The rest of the engine is really beautiful inside!