Author Topic: Motor mount bolt stuck! FIXED!  (Read 501 times)

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Offline kerryb

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Motor mount bolt stuck! FIXED!
« on: August 09, 2024, 09:33:35 AM »
1978 cb550k free after thirty years in the bushes, and the only part that's stuck is the upper rear mounting bolt for the motor.  The head is loose, the nut is off, the bolt is seized into the aluminum case where it goes through the block.  There is no title for the frame, so cutting the frame seems like the good solution to get the motor out.  Would you agree?  I am reluctant to cut the bolt or the mounting spacer.  The further plan is to put vinegar on the bolt till come loose.
« Last Edit: August 10, 2024, 05:54:36 AM by kerryb »
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Offline bryanj

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Re: Motor mount bolt stuck!
« Reply #1 on: August 09, 2024, 09:36:18 AM »
Not uncommon and easy to break the casing, looking at the bike i would say it aint worth a lot so yes cut the mount
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Offline calj737

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Re: Motor mount bolt stuck!
« Reply #2 on: August 09, 2024, 11:53:32 AM »
If you remove lol other mounting bolts, carefully put a floor jack under the oil pan. Lightly raise the jack until the motor moves. Ample penetrating oil and some propane on the motor bosses where the bolt passes thru, and some drive the bolt out with a block of wood to protect it.

Steel and aluminum don’t really seize together. The corrosion of the aluminum case can create enough friction to prevent it sliding out easily though, and the steel bolt could be rusted up to boot.
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Offline denward17

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Re: Motor mount bolt stuck!
« Reply #3 on: August 09, 2024, 12:03:31 PM »
It's probably stuck on the sleeve on the left side.  Mine was anyway.
Plenty of penetrating oil and with channel locks grabbed the sleeve, and started twisting the bolt with a big wrench.

What finally broke it loose was a 3lb hammer.

Offline kerryb

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Re: Motor mount bolt stuck!
« Reply #4 on: August 09, 2024, 12:18:37 PM »
Thanks, I’m up to penetrating oil and a 2lb. hammer, will wait 24 hrs for the bigger hammer!
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Offline kerryb

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Re: Motor mount bolt stuck!
« Reply #5 on: August 09, 2024, 12:22:20 PM »
If you remove lol other mounting bolts, carefully put a floor jack under the oil pan. Lightly raise the jack until the motor moves. Ample penetrating oil and some propane on the motor bosses where the bolt passes thru, and some drive the bolt out with a block of wood to protect it.

Steel and aluminum don’t really seize together. The corrosion of the aluminum case can create enough friction to prevent it sliding out easily though, and the steel bolt could be rusted up to boot.

I figured the bolt rust is mingling with the aluminum corrosion to make too much interference to move
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Offline Don R

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Re: Motor mount bolt stuck!
« Reply #6 on: August 09, 2024, 06:01:32 PM »
 I got one with an impact wrench by working it both ways until it turned and then spun it while tapping the end with a lead hammer. When it came out far enough I stuck an open end wrench just big enough to fit over the bolt diameter behind the head and pulled while spinning. 
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Offline kerryb

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Re: Motor mount bolt stuck! FIXED!
« Reply #7 on: August 09, 2024, 06:03:29 PM »
This bolt has been soaking in penetrating oil for about a week.  Today I put a mapp gas torch to it untill the oil and vineger were boiling, then I did all the tricks, smack with a big hammer and twist with a long bar.  The first movement was a twist in the bolt.  After that is was just worry it out with a hammer and wrench.  The corrosion on the bolt seemed minimal, but the corrosion on the case is significant.

Thanks for the helpful suggestions.
« Last Edit: August 09, 2024, 06:06:27 PM by kerryb »
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Offline RAFster122s

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Re: Motor mount bolt stuck!
« Reply #8 on: August 10, 2024, 03:40:25 AM »
Wire bottle brushes can help remove some of that oxidation now you have the bolt free.  Ran into rusty engine mount bolt and corroded case on a CX500. Bike has been living in Rhode Island on a island off the coast for at least a decade before I bought it and the salt air and high moisture content if the sea air were very unkind to the aluminum case after the factory protective coating deteriorated.
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Aluminum oxidation can be a lot of work to remove if you cannot bead blast or otherwise easily attack that corrosion with traditional methods of dealing with aluminum oxidation.
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Offline kerryb

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Re: Motor mount bolt stuck!
« Reply #9 on: August 10, 2024, 05:53:58 AM »
Fortunately, I have a soda blasting setup, and this one wasn’t in the salt.  My old goldwing in Florida is a bear to keep shiny near the ocean!.  But the sandblasted forks from riding fast are the bigger surprise.
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Offline M 750K6

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Re: Motor mount bolt stuck! FIXED!
« Reply #10 on: August 10, 2024, 11:26:28 PM »
I have to ride over a tidal causeway to get home. On any bare aluminium / aĺloy surfaces and bolt / screw heads, I wipe on ACF50 every autumn. Seems to last quite a few washes and stops any furring. Also prevents any winter condensation from marring polished surfaces. A friend uses a similar product, called XCP. Obviously, keep it away from brakes!

I have used ACF to bring back corroded and furry surfaces, to look like new. Squirt it in the bolt hole, gentle wire brush to get the worst off and ensure it's all coated, leave overnight, then wipe it out. Leave a light coat in there when you put the bolts back in and should be fine.

Offline kerryb

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Re: Motor mount bolt stuck! FIXED!
« Reply #11 on: August 11, 2024, 07:03:38 PM »
Thank you M 750k6, you’re the first person who had a reasonable answer to that.  I’ll get a can for both shops.
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Offline M 750K6

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Re: Motor mount bolt stuck! FIXED!
« Reply #12 on: August 12, 2024, 01:57:28 AM »
Prompted by Rafster's reply about the wire brush. Hope it helps.