Author Topic: Project Frankenbike 750K8 covers on a 75 550K  (Read 2186 times)

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Offline Rgconner

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Project Frankenbike 750K8 covers on a 75 550K
« on: November 07, 2011, 10:47:46 AM »
550K covers are notoriously hard to find.

Frankenbike makes a K8 cover that looked like the right shape and size for a replacement. Not stock, and not "show" but close enough for a set of every day running covers.

FB sent me a set and I test fitted them to the bike. The right side needs some modifications, but the left side was pretty close. So I started there.

I am not a fabricator, so I wanted a solution that would match my skill set: No welding, angle grinding, sheet metal forming.

I also wanted something reversible so that stock covers would work.

At first, I thought a plate that fitted into the existing holes that had other holes to match the ones on the K8 would be feasible. Then the plate could be removed for the OEM/Show set of covers.

However, the fact that the battery and electrical stick out beyond the flat plane of the frame killed that idea. Still doable by a more skilled person, but not by me.

So I thought some more, and went back to my war game/modeling days and recalled we used to use magnets to hold on parts we wanted removable or pose-able.   

I went through a couple of ideas and finally settled on an approach that would require the minimum modification to the covers themselves.

Pictures to follow...
1975 CB550K aka "Grease Monkey"

Offline Rgconner

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #1 on: November 07, 2011, 11:07:39 AM »
Ok, the K8 covers as made by Frankenbike, mocked up on the left side:



The rear upper tab actually lined up, so I kept that.

Then I cut off the other two tabs and glued half inch magnets to them. JB Weld has steel in it, a fact I knew but did not think about when gluing them to the tabs.
The JB Weld actually crept up the sides and started to flow over the top of the magnet! Creepy, and cool at the same time.

Then I glued an angle bracket to the cover, bending it slightly so it would be parallel to the magnet for maximum contact.



I wanted to test the strength of the magnetic bond and the fitting, so I snapped it in place:



Looks pretty damn good for a first try!

The holding power of the magnets is about as good as the remaining stock cover I have, but not nearly as strong as the FB tabs.

The magnets could be considerably larger than they are now, but that was what was available at the local ACE Hardware. I will have to get them off the web or something.

I also am looking at a larger baseplate than provided by the tabs. I am thinking about some carriage bolts I saw that had 1" or larger flat disks instead of hex head. That would be an awesome platform for a larger magnet. Also, they work better when sandwiched between plates, so an anglebracket:magnet:carriage bolt sandwich would be very strong indeed.

 
1975 CB550K aka "Grease Monkey"

Offline YoungRider71

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #2 on: November 07, 2011, 11:28:44 AM »
I used to make miniature models with some friends of mine. whenever we needed magnets we use small "rare earth" magnets. I do not know if they make large ones but they are strong and don't move very easily
74 CB750

Offline Rgconner

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #3 on: November 07, 2011, 11:35:40 AM »
I used to make miniature models with some friends of mine. whenever we needed magnets we use small "rare earth" magnets. I do not know if they make large ones but they are strong and don't move very easily

I am using .5 inch rare earths.

I want to use something like 1" I think. That should be as good as the FB tabs.

They come up to 4" squares with 850lbs of force. Insane.
1975 CB550K aka "Grease Monkey"

Offline Hasenkopf

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #4 on: November 07, 2011, 05:26:53 PM »
lol, I threw a pair of those away last week!
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Offline FrankenFrankenstuff

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #5 on: November 08, 2011, 04:46:56 PM »
I see what you mean about the JB creep. From what I see for that top post, I could make extras to "add on" for the 550K conversion. I want to post a link to this thread in my sidecover thread to help out a couple others. If anything catastrophic happens...I will get you more. Just keep on keeping on with your research. Great work.

Offline Rgconner

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #6 on: November 08, 2011, 06:10:46 PM »
Yeah, I scraped most of it away, it formed a nice bead over the side and top.

I ordered .75 inch squares before I move forward. The holding power is 4 to 5X the round ones I have.

That should put it on par with the standard tab connectors.

Moving the tabs around on your mold might be worth it, I don't know.

All three will have to be moved on the other side, plus some cutting to clear the lock and forward tube.
1975 CB550K aka "Grease Monkey"

Offline Grnrngr

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Re: Project Frankenbike 750K8 covers on a 75 550K
« Reply #7 on: November 08, 2011, 09:26:48 PM »
If you have any old dead hard drives laying around, there are a couple magnets in there that are quite strong.. some folks jbweld them to the bottom of the frame or case somewhere, to trigger the light sensors in the street.
'72 CB750-K2 "PopCycle"
'73 CB750-K2 "Barney"
'77 CB750A   
'83 Virago 500 (red)
'83 Virago 500 (black)

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