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Author Topic: Cb360 Reassembly Help  (Read 3544 times)

Offline cb360j

  • Posts: 61
Re: Cb360 Reassembly Help
« Reply #10 on: May 11, 2018, 01:16:40 »
I can’t see where it’s catching as the valve covers are on when this is happening.
The cam chain tensioner is brand new.

Here is the way the tensioners are put in before I put the tensioner cover on.

Let me cover my bases here:
- the left cylinder is set to top dead center when the “LT” mark is aligned.
- and the hash marks should be completely horizontal to the head surface (top side).

Offline MiniatureNinja

  • Posts: 454
Re: Cb360 Reassembly Help
« Reply #11 on: May 11, 2018, 02:34:08 »
spins freely without the top cover on?

what does that tacho drive look like?
'75 Honda CB360 - thread

Offline cb360j

  • Posts: 61
Re: Cb360 Reassembly Help
« Reply #12 on: May 11, 2018, 10:23:30 »
Correct, spins freely without top cover on. But when it is on, I will rotate the crank the correct direction and about a half rotation later it will stop and not want to move further. I should have looked at what position this was happening to give a better reference.

Tachometer drive gear is perfectly fine. Spins freely, does not seem to have anything wrong.

Offline crazypj

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Re: Cb360 Reassembly Help
« Reply #13 on: May 11, 2018, 10:49:57 »
Do you have thrust washer on cam end? (right side)
It's unlikely but rocker pressure could push cam sideways enough to make things 'catch' ?
You did back off all the tappet adjusters so there was no possibility of them catching on top of valve stems?
It is possible to bend tops of valves enough for them to stick in guides (unlikely but possible)
You did have the front run of chain tight? (all the slack at rear where tensioner lives)
Can you see any 'witness marks' of something catching? (sprocket is 'flat' against mounting flange)
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline cb360j

  • Posts: 61
Re: Cb360 Reassembly Help
« Reply #14 on: May 11, 2018, 11:19:01 »
Do you have thrust washer on cam end? (right side)
It's unlikely but rocker pressure could push cam sideways enough to make things 'catch' ?
You did back off all the tappet adjusters so there was no possibility of them catching on top of valve stems?
It is possible to bend tops of valves enough for them to stick in guides (unlikely but possible)
You did have the front run of chain tight? (all the slack at rear where tensioner lives)
Can you see any 'witness marks' of something catching? (sprocket is 'flat' against mounting flange)



I do not have a thrust washer, and in all honesty, have not heard of this but I will be reading of this immediately. Is this something that is required?

No, I did not back off the tappet adjusters, but I will be doing so as soon as possible.

Correct, front run of chain is tight.

No witness marks of anything. I do not understand what you mean by the sprocket being flat against mounting flange though.


Again, thank you to everyone who has helped thus far.

Offline irk miller

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Re: Cb360 Reassembly Help
« Reply #15 on: May 11, 2018, 11:25:27 »
In the first pic, it appears that your cam chain is all the way at the edge of the tensioner.  This is likely due to the missing thrust washer.  The thrust washer takes up the slack from a small gap at the end of the cam.  You should've had to remove it along with your cam.  But, as PJ would know better, this may have been a service bulletin and not originally installed at the factory.  I can't remember.  Pretty sure he's suggesting that it's possible that the bolts or some part of the cam mount for the cam sprocket is hitting the head.

Offline crazypj

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Re: Cb360 Reassembly Help
« Reply #16 on: May 11, 2018, 11:45:25 »
I've seen one or two with burrs and nicks on cam flange causing sprocket to run out of true, a couple have 'bent' flanges (pretty much just about to break) making chain 'run out' never seen one bad enough to 'lock' motor though.
Can you post pic of inside of rocker cover?
Just in case it's something simple. ;D
If motor turns over with tappets backed out level to rocker arm, cam timing is still 'off'
You can adjust them one at a time to see which is causing problem then pull head and check that valve is OK.
« Last Edit: May 11, 2018, 12:30:50 by crazypj »
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline cb360j

  • Posts: 61
Re: Cb360 Reassembly Help
« Reply #17 on: May 11, 2018, 16:13:48 »
I've seen one or two with burrs and nicks on cam flange causing sprocket to run out of true, a couple have 'bent' flanges (pretty much just about to break) making chain 'run out' never seen one bad enough to 'lock' motor though.
Can you post pic of inside of rocker cover?
Just in case it's something simple. ;D
If motor turns over with tappets backed out level to rocker arm, cam timing is still 'off'
You can adjust them one at a time to see which is causing problem then pull head and check that valve is OK.


In my "infinite" wisdom (complete sarcasm) of my 22 year old self, I somehow skipped over the thrust washer part in the manual.. shame on me.
It is quite possible I took it off when initially removing the cam and then forgot to put it in, but I do not remember the cam having one.

As soon as I get home I will post picture of inside of the rocker cover, it would be a blessing if it was something simple haha.

backing out the tappets is just adjusting valve lash all the way out correct?

Offline crazypj

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Re: Cb360 Reassembly Help
« Reply #18 on: May 11, 2018, 16:51:21 »
Backing adjusters out gives about 3~4mm 'lash' and should allow motor to turn over even if cam timing is still out
Adjust one valve to spec (0.003" ex, 0.002" int) and turn it over.
If you post a pic of cam position before fitting cover I should be able to tell if cam timing is right. I have pictures of 'degree'sd in' cam in m y 360 build/blog so you can see how it should look.
http://www.dotheton.com/forum/index.php?topic=11736.150
Reply 159
 You do have the top tensioner holder in place?
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline Sonreir

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Re: Cb360 Reassembly Help
« Reply #19 on: May 11, 2018, 17:44:32 »
It might also be worth noting that you should have the followers in the "down" position when you put the rocker cover on. Otherwise the tappets might lodge beside the valves instead of sitting over them. This would cause the whole assembly to lock up and possibly bend a valve stem.
Sparck Moto - http://www.sparckmoto.com

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