collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.lostapostlejewelry.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

www.steeltowngarage.com


Author Topic: Cb360 Reassembly Help  (Read 1478 times)

Offline cb360j

  • Posts: 27
Cb360 Reassembly Help
« on: May 09, 2018, 22:17:21 »
Background Story:

Iím newer to the world of Vintage Motorcycles, having had newer Ducatiís but never anything old enough that the dealership didnít work on... shame on me as Iím an engineer and should be doing more. The bike is a 1976 cb360 I got from my neighbor for free, and I decided to just do a full rebuild.

I did all the frame work I wanted, put on a cool snazzy new seat and repainted the frame. Had the cylinders bored in order to put .50 over wiseco pistons in due to the rings being stuck to the old pistons. I am now in the process of reassembling the engine before I put it back into the frame, put the pistons in, cylinders on, head on, all bolted down according to spec.
Now it is time to put the valve covers on, I filled the oil baths with oil and put the gasket sealer from common motor collective, then proceeded to place the valve cover on and bolt it to spec. Before I put the valve cover on, the engine turned freely and I heard air coming from the cylinders. Obviously with the valve covers off, the rocker arms were not pushing down on the valves. The problem is that the engine will spin about half a rotation till it comes to a dead stop, not trying to bend a valve, I donít push down on it any harder and I take the valve cover back off.


Here is my thought process so please help me with this and correct me where I am wrong: the valve cover off means the engine can spin freely with no worries of the valves coming in contact with the engine. When the valve cover on, the rocker arms push the valves down and cause them to come in contact with the piston causing the engine to not complete itís stroke. Assuming the timing is off, or the valves need adjustment, Is this a problem I need to address with the valve cover off? If so, how do I go about this. Thank you in advance.



Here is some pictures of the bike in its current state in case yíall wanted to throw some opinions at that too Haha

Offline crazypj

  • Posts: 12994
  • Split personality, I fake being smart
Re: Cb360 Reassembly Help
« Reply #1 on: May 09, 2018, 22:22:43 »
Sounds like cam timing is off or you didn't tighten cam sprocket  bolts fully?
Trek will be along shortly  8)
'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: 27
Re: Cb360 Reassembly Help
« Reply #2 on: May 09, 2018, 22:32:23 »
Sounds like cam timing is off or you didn't tighten cam sprocket  bolts fully?
Trek will be along shortly  8)



Youíre one of the people I was really hoping would help with this.
The bolts are tightened all the way. One thing I wasnít sure of as I couldnít find it in the service manual, is if there is a correct orientation that the cam sprocket should bolt to the cam, one side or the other?

How do I go about setting cam timing?

Thank you!

Online irk miller

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 7609
  • You've been mostly-dead all day.
Re: Cb360 Reassembly Help
« Reply #3 on: May 10, 2018, 08:51:43 »
You need to align the two hash marks on the cam sprocket with the top edge of the head when the motor is at TDC.  Please confirm this is the case.

Offline crazypj

  • Posts: 12994
  • Split personality, I fake being smart
Re: Cb360 Reassembly Help
« Reply #4 on: May 10, 2018, 11:15:57 »
put left cylinder at TDC then it's just a matter of lining up cam sprocket lines with gasket face. Don't rotate crank, you 'walk' chain around sprocket and when it's in correct position (with front run tight) it will slip onto cam. then rotate cam to line up bolt holes
Just downloadedm picture so I could enlarge it. Looks like cam timing is way off?
« Last Edit: May 10, 2018, 11:50:35 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: 27
Re: Cb360 Reassembly Help
« Reply #5 on: May 10, 2018, 11:39:45 »
I will be doing this as soon as I get home from work. Thank you all

Offline cb360j

  • Posts: 27
Re: Cb360 Reassembly Help
« Reply #6 on: May 10, 2018, 21:50:30 »
put left cylinder at TDC then it's just a matter of lining up cam sprocket lines with gasket face. Don't rotate crank, you 'walk' chain around sprocket and when it's in correct position (with front run tight) it will slip onto cam. then rotate cam to line up bolt holes
Just downloadedm picture so I could enlarge it. Looks like cam timing is way off?



I set the left cylinder to top dead center, then did as you said to walk the chain around the cam till the hash marks arenít aligned with the face of the head surface. I put the cover back on and whenís rotating it still slightly catches. Iím not entirely sure if this is correct or not still. Any insight?

Online irk miller

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 7609
  • You've been mostly-dead all day.
Re: Cb360 Reassembly Help
« Reply #7 on: May 10, 2018, 21:58:37 »


I set the left cylinder to top dead center, then did as you said to walk the chain around the cam till the hash marks arenít aligned with the face of the head surface.
   walk the chain around the cam till the hash marks are aligned with the face of the head surface.  Is that a typo?

Offline cb360j

  • Posts: 27
Re: Cb360 Reassembly Help
« Reply #8 on: May 10, 2018, 22:18:14 »
Haha! Yes that is a typo.

So I restarted undid the bolts to the sprocket and took then cam chain tensioner out.

Here is my steps

Put tensioners in place.
Align Left top dead center
Align sprocket hawk marks
Tighten down sprocket bolts
Install cam chain tensioner holder
Put cover on just to see if anything was better but it still is catching.
Thoughts?

Online irk miller

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 7609
  • You've been mostly-dead all day.
Re: Cb360 Reassembly Help
« Reply #9 on: May 10, 2018, 23:52:01 »
Can you see where it is catching?  It could be a lot of things, and without any idea where the catch originates from it will be hard to figure out.  What does your cam chain tensioner look like, out of curiosity?  There will be loops at the bottom and the top.  Which way do they go?