Topic: Cylinder head removal

[redrider736]

Have a crappy cb 650 motor I am learning  to rip apart and scavenge a few parts from ( Cam,  Oil pan, and anything else that I can reuse down the road) but more too use see how too tear apart a cb motor......

Having a issue getting the cylinder head to come off... All bolts are removed. Does the Cam chain and tensioner need to be removed?

I maybe being too "gentle" with it,  but can/ should I be trying to prying apart the two parts?

[calj737]

Slow down there, Tiger! Yes, the cam chain needs to be removed from the sprocket before you separate head from the cylinders.

Look at the sprocket, there are 2 bolts, 180 degrees apart. You may need to rotate the crank to reach both bolts. Also, you need to loosen the cam chain (there's an adjuster on the intake side, down low. Loosen the nut all the way to create as much slack as possible). Then wiggle the chain off the sprocket, and lift the cam carefully up, and slide it out.

You'll want a bungee handy to hook into the chain to prevent it from falling into the lower cases.

Voice you have the cam, chain, and sprocket out of the way, very carefully begin to lift the head away. Some wiggling, some very gentle prying under the sides (should be a flat spot in the casting) with a wedge. Don't break a fin, or pry to hard. It's been together a long while, and may put up a fight. Some heat around the base may help, and some solvent sprayed into the gasket area to aide breaking down the adhesion.

Go easy, less force = better results. And grab a manual! While you can learn about these engines, you won't know what's truly necessary and the purpose and requirement of all the small o-rings, seals etc that may or may not be there.

[redrider736]

Slow down there, Tiger! Yes, the cam chain needs to be removed from the sprocket before you separate head from the cylinders.

Look at the sprocket, there are 2 bolts, 180 degrees apart. You may need to rotate the crank to reach both bolts. Also, you need to loosen the cam chain (there's an adjuster on the intake side, down low. Loosen the nut all the way to create as much slack as possible). Then wiggle the chain off the sprocket, and lift the cam carefully up, and slide it out.

You'll want a bungee handy to hook into the chain to prevent it from falling into the lower cases.

Voice you have the cam, chain, and sprocket out of the way, very carefully begin to lift the head away. Some wiggling, some very gentle prying under the sides (should be a flat spot in the casting) with a wedge. Don't break a fin, or pry to hard. It's been together a long while, and may put up a fight. Some heat around the base may help, and some solvent sprayed into the gasket area to aide breaking down the adhesion.

Go easy, less force = better results. And grab a manual! While you can learn about these engines, you won't know what's truly necessary and the purpose and requirement of all the small o-rings, seals etc that may or may not be there.

Hey calj737
 Cam & sprocket are already out. Chain (zip tied up) and tensioner are still in (wasn't sure if I needed to remove ).. Thinking it's just stuck in place.. I will look for the pry points and gently go at her tomorrow...

[redrider736]

I read a great thread a few weeks back about swapping 550 & 660 motor parts. The topic of the thread was way above my capabilities. But what I got out of it was there were allot  of interchangeable parts that I could use..  I wanted to swap out my 550 Cam for the 650's and seeing that used 650 Cams were going for $150, I came across full motor for $100.......That's were the 650 motor came into play

http://forums.sohc4.net/index.php?topic=40414.0

[calj737]

All true, hence why you need to be careful and gentle when removing pieces and parts. The head itself has value too. And you certainly want to make sure all the tappets are fully loosened before you commence prying on the head. It's a sure-fire way to bend a valve.

[MiGhost]

Make sure you remove the (2) 6mm bolts at the front, and rear of the cam chain tunnel on the head.  These will be down near the matting surface of the head, and cylinder. They are easily missed when unbolting the head. The tensioner will also need to be unbolted.

Use a putty knife to carefully slide between the head, and jugs to loosen things up.