Topic: Valve cover off - cam wheel won't turn

[egar]

I'm following the shop manual and am ready to take the valve head off, but I can't turn the cam wheel at all so that I can line up the marks at the end of the camshaft like it tells me to in the shop manual. The bike turned over with the kickstarter before I took the bike apart so I figured the engine wasn't seized, I even removed the cam tensioner but the damn cam wheel still won't turn. Is something in the lower case frozen (the wheel at the bottom end of the chain, perhaps?)....

[scottly]

The cam is chained to the crankshaft, they have to turn together!!! Turn the crank to rotate the cam!!!!!

[egar]

A guy at work told me to take the plugs out so I won't be fighting so much compression. I will give that a try.

[MCRider]

What are you using to try and turn the cam? You should use the large nut on the end of the crankshaft on the right hand, ignition side.

Pulling the plugs will help.

[egar]

Thanks, MC. I've never gone this deep into a CB engine and this is my first 750 (done a couple of 550s) so I'm learning as I go. I foolishly thought the cam would turn easily.

[Gordon]

You don't need to line things up to disassemble the head.  Just when reassembling. 

[MCRider]

You don't need to line things up to disassemble the head.  Just when reassembling. 

That's right i think OP was off track there.

But I'll add, it does help to remove the rockers one pin at a time. You (OP, Egar) should turn the engine till the rockers of one pivot pin are on the base circles of the cam (lowest point). Then remove the pin/tower holder bolt and the pin and its rockers. Go to next pin.

Remove the cam bearing caps last. You'll need them in to hold the cam down while you are turning it.

[egar]

This sounds like tricky stuff. Wish me luck.

[egar]

When I tried turning the cam using the bolt at the ignition end of the shaft, all I did was loosen the bolt. It holds two washers at the end. I tried using the kickstarter but all it does is move the whole engine around because I don't have anything to fasten the engine to. Do I have to build some kind of engine stand so that I can bolt the engine to it to kick the starter to turn the cam? I can't believe nobody else has had this problem. I'm thinking about doing every other step in the shop manual so I can get the bloody head off.

[MCRider]

When I tried turning the cam using the bolt at the ignition end of the shaft, all I did was loosen the bolt. It holds two washers at the end. I tried using the kickstarter but all it does is move the whole engine around because I don't have anything to fasten the engine to. Do I have to build some kind of engine stand so that I can bolt the engine to it to kick the starter to turn the cam? I can't believe nobody else has had this problem. I'm thinking about doing every other step in the shop manual so I can get the bloody head off.

I guess we should confirm what you are working on. I'm assuming CB750?

What you describe trying to turn is unknown to me. There is a large nut , not bolt, about 17mm or so. It is so designed that it will not loosen upon turning it in either direction as it is held on to the ignition drive stud with a 6mm (10mm head) nut. it is there for the sole purpose of turning the crankshaft for tune up and disassembly duties.

Lets clean up the context, which bike, etc.

Rereading your post, are you on the camshaft or the ignition end of the CRANKSHAFT? The crank is where you should be. Turning it will turn the cam.

[egar]

MC, I appreciate your taking the time to respond with such detail. I have a 1970 cb750k, not k1, model. I will go back out and take a peek to see what you are referring to....

[MCRider]

MC, I appreciate your taking the time to respond with such detail. I have a 1970 cb750k, not k1, model. I will go back out and take a peek to see what you are referring to....

Great, nice bike. I'm thinking you're stuck on the cam.

Have you removed the chrome ignition cover on the lower right side of the engine, 2 screws?

Behind it is the ignition and the crank nut we are speaking about.

If you haven't then please do and all this will become clear.

[egar]

It started to become clear when I thought about what you were saying. I took that cover off for the first time today but never made the connection. Thanks so much for your patience. I can't believe the shop manual doesn't mention taking the ignition cover off so as to turn the crank to turn the cam where it needs to be. Am I catching on? Thanks so much.

[MCRider]

It started to become clear when I thought about what you were saying. I took that cover off for the first time today but never made the connection. Thanks so much for your patience. I can't believe the shop manual doesn't mention taking the ignition cover off so as to turn the crank to turn the cam where it needs to be. Am I catching on? Thanks so much.

Yay! You got it. Its all downhill from here.   

[MJL]

When I tried turning the cam using the bolt at the ignition end of the shaft, all I did was loosen the bolt. It holds two washers at the end. I tried using the kickstarter but all it does is move the whole engine around because I don't have anything to fasten the engine to. Do I have to build some kind of engine stand so that I can bolt the engine to it to kick the starter to turn the cam? I can't believe nobody else has had this problem. I'm thinking about doing every other step in the shop manual so I can get the bloody head off.

I have a couple pieces of square steel tube, about 2-1/2x2-1/2. I set the motor on them and then clamp them down to the bench. Seems to hold the motor pretty well.

[egar]

MJL,

Yeah, I have to improve the way I secure the engine. This is the farthest I've been into a CB. The first 550 was more cosmetic, the second one went to the frame but didn't require engine rebuild, so this KO I guess is a natural progression.