Starting from scratch :) tank&petcock questions

[Volker_P]

The reason for opening was that the bike would not start, you could hear the chain inside spinning, but it was like it couldn't catch something to start it .

This is a starter clutch issue. Have a look here.

I could start it by pushing, in 2nd gear, but it would run very rough, I was constantly twisting the throttle to keep it running. Mechanic said that it could be the cam chain tensioner.

Sure it could be. Or something else. Maybe it was just runing on two or so.
I love that kind of mechanic.

Also, since it was from the beginning running rough on slower rpm's, I thought it would be good idea to clean the tank and carbs (esp. slow jets).

Very good idea!

No precise idea about that missing part. But it looks like something cracked off by a too long bolt, it does not look like a moving part. Is there a thread inside?

Here is how it should look like at the yellow circle: viewtopic.php?f=4&t=8853&start=25. Guess it is a cast knob or so. So probably nothing missing there.

[mojoblues]

@Volker: What are the symptoms of a starter clutch issue? From the other post it looks that could be it. But to check for that issue, I need to put everything back, right? My engine is in pieces at the moment, and before I put it back together, I'll need to order and install all the new gaskets.
Do I need anything else or this looks like a complete thing: http://www.ebay.com/itm/Dichtsatz-kompl ... c9&vxp=mtr

What about these rubbers under the cylinder head cover:





I don't know even what they are called

[Spyug53]

Mojo, that looks like the full gasket set. The O-rings fitted to the head provide a seal for the oil passages.

As you have determined, you can't test anything until you have the engine back together so that needs to be the priority. Take your time with the reassembly, however, to make sure you don't leave anything out. Also be very careful that the cam goes back in the exact position it came out and the sprocket matches the correct link on the chain or you will have a miss timed cam which will result in bent valves or worse. Read the chapter in the manual very closely until you are sure you understand it. Again it is not difficult but must be done correctly.

Once you have it together then you can worry about the starter issue.

Remember, "slow and steady wins the race" so don't rush as that generally results in making mistakes which you don't want. You can do it!

[mojoblues]

OK, so I have enough time to find a good torque wrench until the gasket set arrives. Everything (I hope) I took down is labeled correctly so with the manual I shouldn't have to much problems. But will take photos and post here to check.
In the meantime, I need to clean those carbs (struggling to pull out the slow jets), measure the cables to be replaced, clean up the rust from exhaust and some small parts ...
And yes, I will take it slowly, patience is all I have

[Spyug53]

I find patience is something you really need to have to work on old bikes as there is usually quite a bit of waiting involved in a restoration. As you note, however there are always lots of little things to attend to so you can stay occupied.

I am waiting to pick up my 650 and likely will get it at the end of the week but our weather has turned very cold of late, -10C at the moment and I'm getting too old to work in a freezing garage ( even with space heaters it barely gets above freezing) so I might not get much done until the spring. It may be a long winter Someday I'd like to have a fully heated shop.

Well chip away at what you can and let us know when your parts arrive.

[mojoblues]

@Volker: Sir, I take my hat off to you! It looks like IT IS a starter clutch problem - I just don't know how you got it from my very bad explanation!
This is what my bike sounds (somebody else's video): http://www.youtube.com/watch?v=hDUKb7JbzZE

Plus, I've found other starter clutch videos on YT that sounds like mine. So, I'll put my bike together when parts arrive and try to fix that.

Thank you!!!

[Folsoml]

@Volker: Sir, I take my hat off to you! It looks like IT IS a starter clutch problem - I just don't know how you got it from my very bad explanation!

Because he is a genius!

[MiGhost]

@Volker: Sir, I take my hat off to you! It looks like IT IS a starter clutch problem - I just don't know how you got it from my very bad explanation!

Actually it was an excellent explanation!!
The vital clues were that it was spinning free, and not catching.

You will find either the torx head bolts (21) that hold it together have come loose, or the outer clutch (17) has been damaged (cracked around spring pockets).

Part schematic for reference
NOTE:Red numbers in () = item #s in following schematic
http://www.partzilla.com/parts/search/H ... parts.html

The starter clutch is a sprag clutch that will spin freely in one direction, and lock up in the opposite direction. What happens is when the bike does not start properly. The starter clutch kicks free when the engine fires, but gets slammed back into locking postion if the engine does not stay running. This causes the damage to the outer clutch, and springs.

You will need to replace the springs (18), caps (19), and rollers (28) at a minimum. If the outer clutch (17) shows any signs of cracks, or damage (bulging) around the spring pockets. I would highly advise that you replace it also.

When you reassemble the starter clutch. Use locktite blue on the torx bolts to help keeping the mform coming loose.

[mojoblues]

MiGhost, thank you for very detailed explanation!
It doesn't sound like it will be very hard to find and fix offending parts. Since the engines on cb650 variations are similar, will these parts from custom model fit Z model? Is the starter clutch the same or is it model specific?
I suppose I need to put the engine together before fiddling with the starter clutch, right?

[cb650]

Any sohc 650 starter clutch will work.