Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 32

Thread: Tracking down a knock on a '78 GS400. Need help getting the cylinder off.

  1. #21
    Gorminrider is offline Forum Sage Past Site Supporter
    Super Site Supporter
    Join Date
    Aug 2012
    Location
    British Columbia, Canada
    Posts
    4,563

    Default

    So wood's the winner, eh? Maybe I'll head down to the Homeless Despot this week and grab one for my whacking purpose...
    Your method isn't working and I'm merely suggesting a different technique, harmless to try.
    Buy? don't Buy. At least don't buy a blisterpacked and degenerate iteration of a very simple tool until you know you really want it.
    No hammer? find a nice rock. and so on...

    Cut a scrap broomstick, or a straight branch of a trees, or a 2x2 or a 1x2 of stout wood to say 12 or 18" , and whack it with a steel hammer. The idea being you can apply more force at a smaller spot without marking the engine or accidentally, say, breaking fins off... Plus you can get target cramped places where that's wanted someday.
    Mallet? a chunk of 2x4 or thick branch. More elaborately, a piece of short-grained wood that won't split right away, drilled to put a handle into. Some homemadse will fall apart in your hands after a few uses, some will be your lifelong friend...
    Last edited by Gorminrider; 10-13-2021 at 11:21 AM.

  2. #22
    Gorminrider is offline Forum Sage Past Site Supporter
    Super Site Supporter
    Join Date
    Aug 2012
    Location
    British Columbia, Canada
    Posts
    4,563

    Default



    see the 6 springs? (black arrow)I called this "the clutch boss" for lack of imagination but the parts diagram calls it 'clutch gear. It's just a thought, per your description though.

  3. #23
    Join Date
    Oct 2021
    Location
    indianapolis in
    Posts
    24

    Default

    Quote Originally Posted by Gorminrider View Post


    see the 6 springs? (black arrow)I called this "the clutch boss" for lack of imagination but the parts diagram calls it 'clutch gear. It's just a thought, per your description though.
    I just got to these today. I checked my actual clutch springs and they are 1mm out of minimum spec but the manuals don't list any specs for these springs on the back. There are two separate kinds in alternating pattern.
    Any place I can find specs for these? None of them seem particularly loose.
    $100 1978 GS400 Rebuild.
    - Solid state LED compatible blinker relay
    - All Balls taper bearing steering stem mod
    - BRC ignition coils and NGK caps
    - Custom cafe seat
    - USB charging port
    Work in progress (this bike will be my coffin).

  4. #24
    Gorminrider is offline Forum Sage Past Site Supporter
    Super Site Supporter
    Join Date
    Aug 2012
    Location
    British Columbia, Canada
    Posts
    4,563

    Default

    No though it might be in a shop manual somewhere...twas just a thought. Taking the motor of a running bike entirely apart to find an indefinite noise is beyond my experience. ..... you didnt find any other suspects in there? loose keyways? small bolts flicking around?
    Maybe taking the sump plate off is the next. Or double-checking the cam-chain tensioner. Perhaps the chain was slapping. Have a look down the tunnel for sign of that. Have a good look at the camchain blade too. Pieces can come off the plastic ones- they are getting really old these days.

    Usually you can troubleshoot worn bearings or rings or valves before you take the cylinders off.

    If you're still determined to rip your cylinders off (which I'm not imagining as a discovery method for a knocking or rattling) and really can't find any reason for them not to release, I guess a wood-chisel whacked at the gasket all-round is the final blow. It's better than a screw driver. But it's so easy to mar surfaces and I didn't tell you to do it and I wouldn't until I'd determined it was all sacrificial...
    Last edited by Gorminrider; 10-13-2021 at 08:19 PM.

  5. #25
    Join Date
    Oct 2021
    Location
    indianapolis in
    Posts
    24

    Default

    Quote Originally Posted by Gorminrider View Post
    No though it might be in a shop manual somewhere...twas just a thought. Taking the motor of a running bike entirely apart to find an indefinite noise is beyond my experience. ..... you didnt find any other suspects in there? loose keyways? small bolts flicking around?
    Maybe taking the sump plate off is the next. Or double-checking the cam-chain tensioner. Perhaps the chain was slapping. Have a look down the tunnel for sign of that. Have a good look at the camchain blade too. Pieces can come off the plastic ones- they are getting really old these days.

    Usually you can troubleshoot worn bearings or rings or valves before you take the cylinders off.

    If you're still determined to rip your cylinders off (which I'm not imagining as a discovery method for a knocking or rattling) and really can't find any reason for them not to release, I guess a wood-chisel whacked at the gasket all-round is the final blow. It's better than a screw driver. But it's so easy to mar surfaces and I didn't tell you to do it and I wouldn't until I'd determined it was all sacrificial...
    To be honest at this point the only reason I'm still determined to get the cylinder off is it will make it easier to de-carbon the pistons without getting shmutz all in the cylinder/case and before I cracked it open the compression was at about 90 psi. Haven't noticed any issues with the valves or seats, tappet clearances were acceptable. If it wasn't for the low compression I probably would have started with the clutch. But I already have a new set of rings sitting around and I certainly don't mind taking things apart even if it just ends up being for the experience. Sure, it might seem silly to be tearing the thing apart now, but I either find nothing and I learn a ton about my engine in the process and also end up with the peace of mind of knowing nothing is actually broken, or I find something broken and the end result is the same.

    But yeah, if it wasn't for the low compression I would probably just be putting the head back on at this point.
    $100 1978 GS400 Rebuild.
    - Solid state LED compatible blinker relay
    - All Balls taper bearing steering stem mod
    - BRC ignition coils and NGK caps
    - Custom cafe seat
    - USB charging port
    Work in progress (this bike will be my coffin).

  6. #26
    Gorminrider is offline Forum Sage Past Site Supporter
    Super Site Supporter
    Join Date
    Aug 2012
    Location
    British Columbia, Canada
    Posts
    4,563

    Default

    ah. 90# is low especially if it's just one side. But the valves affect compression too. Bad rings would result in fouled plugs and smoke, bad valves not so unless the seals were pretty bad? ...anyways I" did-over" the valves on my gsx400E, found bent ones and it fixed the "one-side low" problem.

  7. #27
    Join Date
    Oct 2021
    Location
    indianapolis in
    Posts
    24

    Default

    Quote Originally Posted by Gorminrider View Post
    ah. 90# is low especially if it's just one side. But the valves affect compression too. Bad rings would result in fouled plugs and smoke, bad valves not so unless the seals were pretty bad? ...anyways I" did-over" the valves on my gsx400E, found bent ones and it fixed the "one-side low" problem.
    Both sides were low. I was debating borrowing a valve spring compressor and removing them to fully examine them.
    $100 1978 GS400 Rebuild.
    - Solid state LED compatible blinker relay
    - All Balls taper bearing steering stem mod
    - BRC ignition coils and NGK caps
    - Custom cafe seat
    - USB charging port
    Work in progress (this bike will be my coffin).

  8. #28
    Nessism's Avatar
    Nessism is online now Forum LongTimer GSResource Superstar
    Past Site Supporter
    Super Site Supporter
    Join Date
    Mar 2006
    Location
    Torrance, CA
    Posts
    33,774

    Default

    Have you popped the cylinder loose yet? We are going on 8 days now. It ain't that hard.

  9. #29
    Join Date
    Oct 2021
    Location
    indianapolis in
    Posts
    24

    Default

    Quote Originally Posted by Nessism View Post
    Have you popped the cylinder loose yet? We are going on 8 days now. It ain't that hard.
    No I haven't. To be fair I have only been working on it in passing time.

    I really am running out of ideas. I tried jammed a plank under the block where the cam chain tensioner goes and lifting, but no dice.

    This definitely shouldn't be this hard which is getting frustrating because it feels like I'm missing something. Yeah the gasket is old but if there's nothing else holding it I shouldn't have seen SOME progress by now, even just a lifted corner or something.

    I could have the whole bike put back together in an afternoon if I can just get this damn cylinder off so I can clean the Pistons and change the rings.
    $100 1978 GS400 Rebuild.
    - Solid state LED compatible blinker relay
    - All Balls taper bearing steering stem mod
    - BRC ignition coils and NGK caps
    - Custom cafe seat
    - USB charging port
    Work in progress (this bike will be my coffin).

  10. #30
    Nessism's Avatar
    Nessism is online now Forum LongTimer GSResource Superstar
    Past Site Supporter
    Super Site Supporter
    Join Date
    Mar 2006
    Location
    Torrance, CA
    Posts
    33,774

    Default

    How about a crowbar? Use duct tape on the tip so it doesn't gouge the aluminum. Cram it in the gap between the tab that stick out and the block and then lift up.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •