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Author Topic: Motor locked up in a 73' cb500 and trying to get the head off HELP!!  (Read 1187 times)

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Offline dergs713

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Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« on: January 26, 2012, 05:43:27 pm »
Hey guys fell upon a 1973 honda cb500.  Motors locked up, and in the process of taking it apart... I have ran into a bump in the road...  The cam chain cannot be rotated, meaning i can not get to one of the cam gear bolts, meaning the top end of the motor is not coming off.( at least I think thats how it goes..)  I want to get to the pistons to see the damage. If anyone knows of a way i can get the head off without breaking the chain im all ears.  also any other route would work too. Thanks
Matt
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Offline CBGhia

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #1 on: January 26, 2012, 05:46:33 pm »
So drop some Marvels Mystery oil down all of the spark plug holes and let it sit for a day or two or three.  Then try bumping the engine over using the bolt on the stator side.  You may get it freed up.  I have seen more than a few "locked up" engines come free this way.
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Quote from: dave500 on February 14, 2014, 03:53:33 am
if you dont trial spin the camshaft in the head and cover you are a novice,with no natural mechanical appitude,destined for destruction.
"The cleaner the dipstick, the closer to God." -Rev. Horton Heat
“Faster, Faster, until the thrill of speed overcomes the fear of death.”  - Hunter S. Thompson

Offline dergs713

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #2 on: January 26, 2012, 05:50:49 pm »
Ill give it a go.. all i had at the time was wd-40.  been soaking for a couple hours now. Thanks for the idea tho man. Ill try it out tomorrow

Also, anyone know what i am in store for.... new pistons and head, or a lot of elbow grease.. Im new to the game..
Matt
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72500john

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #3 on: January 26, 2012, 06:09:07 pm »
take it one step at atime and do it right so you dont hve to go back and do it over( been there done that). check out kano ladratories for some neat oil called kroil. i think they will send you some for a good price. neat stuff. used it for years. lot of folks dont know about this stuff but heres the link.

http://www.kanolabs.com/

should help things to loosen up.
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Online bryanj

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #4 on: January 26, 2012, 10:07:27 pm »
If it's that locked i suspect you will need oversize piston kits and a rebore and to be honest i would split the chain and replace it for the cost of it
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Offline CBGhia

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #5 on: January 27, 2012, 04:31:17 am »
If the pistons froze from corrosion, you may be able to pull them, slap some new rings on it and just do a hone on the cylinders.  I would probably do a new cam chain, at the least new sliders.  You may or may not need to have the head decked. But, it could be much worse.   No telling till ya get into it.  If the marvels frees it up, I would say you are in good shape.    Many people on the board are riding bikes that were freed up this way and they never even pulled the heads.
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Quote from: dave500 on February 14, 2014, 03:53:33 am
if you dont trial spin the camshaft in the head and cover you are a novice,with no natural mechanical appitude,destined for destruction.
"The cleaner the dipstick, the closer to God." -Rev. Horton Heat
“Faster, Faster, until the thrill of speed overcomes the fear of death.”  - Hunter S. Thompson

Offline cmonSTART

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #6 on: January 27, 2012, 05:01:21 am »
I was in the same situation with my 750f.  I ended up just breaking the cam chain which I will replace later. 
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Offline MRieck

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #7 on: January 27, 2012, 05:09:42 am »
Quote from: cmonSTART on January 27, 2012, 05:01:21 am
I was in the same situation with my 750f.  I ended up just breaking the cam chain which I will replace later.
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 There you go. ;)
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Offline dergs713

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Re: Motor locked up in a 73' cb500 and trying to get the head off HELP!!
« Reply #8 on: January 27, 2012, 10:05:10 am »
Thanks guys, im goin to let it soak over the weekend, and see where im at. ill keep ya posted.
Matt
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