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CB500T Engine - What a Mess!

Thread: CB500T Engine - What a Mess!

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  1. KnucleBusting360's Avatar

    KnucleBusting360 said:

    CB500T Engine - What a Mess!

    "Clean Up in Aisle 5!" ... oh boy do I have a mess! ... finally got the engine cracked open this weekend ... it was frozen so I expected bad news, but what I have is a nightmare ... lots of corrosion and grime! I'm fairly certain the piston heads are not salvageable, but I'm also wondering about the whole engine at this point ... this bike sat in a barn for 30 years and the whole thing is pretty crusty ... I plan on breaking the engine down completely soon ... have to see what awaits me in the gear box as well ... any early thoughts? The starter motor rotor was completely missing See the corrosion on the clutch basket gear ... is that repairable or toast? The alternator rotor also has similar corrosion ... Ugh ...

    CB500T Engine - What a Mess!-image.jpg CB500T Engine - What a Mess!-image-1.jpg CB500T Engine - What a Mess!-image-2.jpg
  2. RyanNH's Avatar

    RyanNH said:
    My 450 was in a similar state. Frozen after sitting almost 30 years as well.
    Head and cylinders are at the machine shop now.
    It's hard to see from your pictures how deep the corrosion is on the clutch basket. Is is superficial or are the teeth in bad shape?
  3. 66Sprint's Avatar

    66Sprint said:
    We can see the alternator rotor in the pics and it looks fine... Did you mean the steel core of the stator windings?
    "I have a mind like a steel trap.....Old and rusty, of antiquated design, and hard to get stuff back out of...."
    Contact info: E-mail; [email protected] Phone; 540-525-5199
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  5. 76TWIN's Avatar

    76TWIN said:
    More pics (and closeups) of the various angles of the engine would help.
    You'd be surprised what can be cleaned up and still serviceable. Unless the pistons are scored badly and out of specs as they are now, I would clean them up and see.

    Hell... My own CB500T engine didn't look much better when I first got it and I managed to reuse almost all of its parts in rebuilding.
    '76 CB500T Frankenbike
    '73 CL450 (basket case for now)

    Carpe narem.
  6. misterguitar's Avatar

    misterguitar said:
    You would be shocked regarding those pistons. I bet all the rust is from the iron sleeve, not the piston.
  7. KnucleBusting360's Avatar

    KnucleBusting360 said:
    Gurus ... any suggestions on how to start cleaning these gooey parts? I was thinking of starting by soaking them in some gasoline for a while to loosen up the grime ... what would you suggest scrubbing them with? Especially the piston heads and inside cylinders ... I know I'm going to have to hone the cylinders (minimally), but just interested in the best way to get started and suggestions of scrubbing media (i.e. 0000 steel wool, scotch brite pads, etc ...)

    Thanks as always ... Bill
  8. 76TWIN's Avatar

    76TWIN said:
    I have had good results using Seafoam as well as acetone as a soak for engine parts and then just scrub with a brass brush.
    '76 CB500T Frankenbike
    '73 CL450 (basket case for now)

    Carpe narem.
  9. JamesPal's Avatar

    JamesPal said:
    Quote Originally Posted by 76TWIN View Post
    I have had good results using Seafoam as well as acetone as a soak for engine parts and then just scrub with a brass brush.
    There is some wisdom here. Make sure any thing you use to scrub the parts is softer than the material the part is made of. Especially the ring groves on the pistons. The rings must seal to the pistons as well as the cylinder walls. Just pain detergent in warm water will clean up the oily parts. Engine cleaner from the parts stores can be used. Be sure to oil the parts up after cleaning so they don't rust.
    Jim Palmer
    '85 GL1200I (Garage Find)
    '81 GL1100 STD (Project)
    CB450 K5 Done
    What I learned from Restoring a CB450 K5
    Watch Mike and Jim Take on Mt Erie Washington State
    "If everything seems under control you are not going fast enough" Mario Andretti...
  10. FrisianWheel's Avatar

    FrisianWheel said:
    Quote Originally Posted by 76TWIN View Post
    ...You'd be surprised what can be cleaned up and still serviceable...
    Absolutely agree on that! I'm still working on a similar engine that was even in worse shape because some genius removed the spark plugs befor letting it sit outside (in Pennsylvania) for who knows how many years. Just break it down, clean and inspect everything.
    Last edited by FrisianWheel; 04-26-2019 at 01:18 AM.

    1972 CB450 K5
    1975 CB500T
    1972 CB450 K5 - in progress
  11. Brent's Avatar

    Brent said:
    It is amazing what can be brought back too life. Somewhere here there is a thread from an Aussie where he has pulled an old bike from the sand on a beach and resurrected it. I can't remember what he had to replace but looking at the motor it was unbelievable it ever ran again.

    I use diesel and nylon brushes for most of my cleaning, as James said make sure the scrubber is softer than the scrubee. Clean them but don't dry them, the oiliness of the diesel will keep the bare metal parts from rusting until assembly. Then I wipe parts down as I use them. Pour the diesel through a coffee filter when your done and you can use it many times.

    I assembled a simple washer. laundry tub, a five gallon white pail, a minnow pail with newspaper(filter), a backpack sprayer handle and a cheap 12vdc pump. Pumps out of the pail, through the sprayer into the tub and drains back to the pail through the filter. The whole set up was less than $50 and I use it all the time.
    Similar pump to this, $25Cdn.
    CB500T Engine - What a Mess!-81q0q9g1s5l._sl1500_.jpg
    Last edited by Brent; 04-26-2019 at 06:18 AM.