CB350 Cylinder Head Removal

Discussion in 'Old's Cool' started by Scheidty, May 29, 2011.

  1. Scheidty

    Scheidty Adventurer

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    [​IMG]Hey guys.

    I've been attempting to replace a leaking cylinder head gasket (or points cover gasket, can't tell which one) on my 72 CB350. I have a couple online shop manuals and a clymer. I have a few questions about the process as I'm having trouble understanding some of the steps. I will be posting pics of the process as I go along as well. Any help is appreciated!

    The one manual states to " Align the stator index mark to the "LT" on the A.C. Generator rotor (top dead centre of the exhaust stroke) to approximately 10 degrees ATDC and then remove the sprocket alignment bolt, followed by turning the rotor to align with a point approximately 10 degrees ATDC of the compression stroke and then remove the remaining sprocket setting bolt."

    Does this just mean that I align the LT to the index mark, which should be the top dead centre of the exhaust stroke. Then move the rotor to 10 degrees ATDC? How do I know where ATDC is?

    The Clymer states " Place a wrench on the alternator rotor bolt and rotate the engine until you have room to work on one of the camshaft sprocket retaining bolts. Remove that bolt, then rotate the engine until you can reach the remaining bolt and remove it. With the L mark on the cam sprocket facing upward, pull out the camshaft from the right side"

    Is the process basically the same as the one in the shop manual? Which one is the better process? Thanks!

    And also, should I be using gasket cement or any other adhesive when installing the new gaskets? Thanks again!

    Here's a link to photobucket and some photos. I'll try to figure out how to post them on here though.

    http://s1181.photobucket.com/albums/x436/scheidty/
    #1
  2. Horatio0163

    Horatio0163 Been here awhile

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    Hey hey! I just pulled the head on my cb350 this week! Likewise I have a variety of pdf Honda manuals and a Clymer's. The processes described are essentially the same. The Honda manuals are just specifying which bolt to remove first. The LT mark on the rotor indicates TDC (top dead center) on the left cylinder. In a 4-stroke engine the piston is at TDC twice-- exhaust/intake and compression/power.

    The Honda manuals are telling you to find the exhaust/intake TDC (both rocker arms for the valves of the left cylinder should be tight--exhaust just closed and intake is just opening. I think the L mark on the cam sprocket will be down.), go just a little further to make access easier, and remove the sprocket bolt that you can get to.
    Then you rotate the crankshaft one full revolution until you're back at LT-- the compression/power TDC (both rockers are loose,and I believe the L mark is visible on the cam sprocket.), go a little past it for easier access and remove the second bolt. Then you can slide the camshaft out the right side. It takes a bit of fiddling to get the shaft out, in my experience.

    You'll figure it out. This isn't a terribly complex machine. Good luck and feel free to ask any questions you may have!
    #2
  3. Scheidty

    Scheidty Adventurer

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    #3
  4. Scheidty

    Scheidty Adventurer

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    Some photos. Is this wear normal? It's the same on all four "columns" near the cam chain.

    Attached Files:

    #4
  5. Scheidty

    Scheidty Adventurer

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    Managed to remove the side covers and take out the rocker arm pins and rocker arms.

    Attached Files:

    #5
  6. Scheidty

    Scheidty Adventurer

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    Three out of four rocker arms were smooth like the one in the photo. However, one of them had slight pitting near one of the edges, but looks like it shouldn't need to be replaced (based on the look of other folks rocker arms and magnitude of pitting).

    Attached Files:

    #6
  7. Scheidty

    Scheidty Adventurer

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    How can I tell if the leak is coming from the points cover gasket or the cylinder head gasket. There was some oil in the points cover area, which makes me think that it's just the points cover. However, if it ends up being the cylinder head, I'll have to remove the engine and tear down part of the top end again. What do you guys think?

    Attached Files:

    #7
  8. Horatio0163

    Horatio0163 Been here awhile

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    I'd say the wear shown in your picture is very not normal. It looks like some PO has done some modification. There isn't anything moving near there that would cause that kind of wear.

    You've got it this far. Just replace both the head gasket and the point cover gasket. It's just another few minutes of work, and I'd say it's probably worth it. Plus then you can see the condition of your cylinders and test your valves for leakage.
    #8
  9. RLieu67

    RLieu67 Adventurer

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  10. Scheidty

    Scheidty Adventurer

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    Cam chain roller. I'm assuming it's worn enough to warrant replacement.

    Attached Files:

    #10
  11. Scheidty

    Scheidty Adventurer

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    Took these two cam chain sprocket bolts out without realizing that the two are actually different. I"ll have to figure out which one goes where when I rebuild the engine. What special tools might I need to replace the cam chain roller?

    Attached Files:

    #11
  12. Actionabe

    Actionabe Adventurer

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    You should not need any special tools to replace the tensioner wheel, you may want to look at the slipper type cam tensioner, it's supposed to be pretty good. I'll find out once I get my engine running..got mine from boretech..
    #12
  13. LashLarue

    LashLarue Been here awhile

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    Not my photo, same as earlier in thread:

    http://www.advrider.com/forums/attachment.php?attachmentid=268392&stc=1&d=1306892602

    Sorry to revive an old thread but this is where I am on a rebuild of a 71 SL350. The engine is frozen and I am trying to get the cam out. The cam chain has almost no slack. I have one cam gear bolt removed but can't turn the engine to get to the second gear bolt.

    Am I right to assume that it is time to snap the chain? Not sure how to do that and keep chain and broken parts from diving into engine. In fact I am not sure how to break the chain since it is all on the gear.

    The engine is seized and there will be no alignment to TDC. Bet that causes problems later.
    #13
  14. Hurricane Bob

    Hurricane Bob formerly: Bomber1965

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    [​IMG]

    or...

    grind the pin heads and tap out a link. rags /magnet to catch loose bits.



    :freaky
    #14
  15. Bloodweiser

    Bloodweiser honestly

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    Do what you gotta do.
    If it's seized, I'd be going through the bottom end too -
    so I wouldn't worry about bits getting places they shouldn't.
    It'll force you to be more thorough.
    #15
  16. LashLarue

    LashLarue Been here awhile

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    That looks like fun! Really can't do it with the chain on the cam gear w/o cutting through and damaging the gear.
    #16
  17. mike in idaho

    mike in idaho Been here awhile

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    Remove both end cap/cam bearings from the head and the cam chain tensioner assembly first. That may give you enough slack to work the cam around to access the bolts.
    #17
  18. LashLarue

    LashLarue Been here awhile

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    That worked! When I took the end cap from the side that drives the tach, the rocker arms slackened and I could remove them. When they were out, the cam became loose. I can tell that I can not only get the cam out, I might not have to remove the chain.

    I still worry about re-assembly, as nothing is at the timing marks.
    #18
  19. Harry94025

    Harry94025 Been here awhile

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    The bolt with the non-threaded shank will be a precision fit for one of the holes in the sprocket. That locates the sprocket correctly...
    #19
  20. LashLarue

    LashLarue Been here awhile

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    I think I am moving over to another thread instead of hijacking this one.
    #20