Author Topic: CB750 side covers build? (Read 1832 times)

wolf550 · « **on:** August 12, 2020, 10:19:34 PM »

So I took a break from the 550 side covers.
every time I tried to make another set they would self destruct on me!
I went ahead and bought those CB750 side covers to see where I was at.
step one:make a big enough casting mold!
step two:make sure the sides of the covers would mold!
step three: make the mold!
so far the CB gods are smiling down at me.

seanbarney41 · « **Reply #1 on:** August 13, 2020, 02:54:45 AM »

Very cool...keep developing that skill.

wolf550 · « **Reply #2 on:** August 13, 2020, 08:12:17 AM »

thanks seanbarney
got a 750 oil tank in the mail the other day and it looks like there isnt any shrinkage!!!
now i gotta find someone close to me with a frame yo check the other side.
anyone in orange county?

wolf550 · « **Reply #3 on:** August 13, 2020, 09:02:32 PM »

a few more pics.
you can see where the small areas where it did not make it at the end of the pour.
it seemed a shame to scrap these two so I'm gonna go ahead with making these.
still some more clean up on the fronts to make smooth for the shine.
since these again are very heavy indeed I'm gonna opt for the tap with a m6 bolt through the grommets.

wolf550 · « **Reply #4 on:** August 16, 2020, 11:03:54 AM »

while still on the hunt for a frame to match up the left side to I went ahead and started working on the right some more.
Since the prongs line up with the grommets pretty well I am going to see on the next set just keeping them on and use a die to screw a nut and spacer to.

seanbarney41 · « **Reply #5 on:** August 16, 2020, 11:24:19 AM »

tell us a little about your finishing process...lots of rough sanding and filing?

wolf550 · « **Reply #6 on:** August 16, 2020, 11:49:48 AM »

I don't have as much experience on finish so I try not to exhaust myself on the sanding and polishing.
I could take my set of 550 side covers to a polishing service place and they could get them to shine in the dark probably.

After cutting off all the excess aluminum I go at with the angle grinder 40 grit disk.
next is the palm sander with 60 and 120 grit.
from 400 to 3000 I only use a 1.5X3" piece of wet sand paper silicon carbide side to side one way and then up and down the other.
a couple of minutes.
after clean up I have a the H.F. 2 Inch buffing wheel that attaches to a drill.

(Note) these side covers I am using have the recess area for the side cover emblem.
I had to cover this up but there is still and indent that wouldn't fill if I was to cast
so I lump this out of the sand mold. this is noticeable on the casting after removing from the mold.

I have to order the smooth set and the K0 side covers without the emblems to make it alot easier after casting on the clean up.

you can see a pretty good change on the aluminum with minimal effort sanding so I can only imagine taking these to a shop.
here are some pics

754 · « **Reply #7 on:** August 16, 2020, 12:37:58 PM »

I gave a single cast 750 oil tank sidecover. If I run a cross it , will take pics of the back. When MPD cast them they had a pretty good foundry set up..

wolf550 · « **Reply #8 on:** August 16, 2020, 12:46:30 PM »

Quote from: 754 on August 16, 2020, 12:37:58 PM

I gave a single cast 750 oil tank sidecover. If I run a cross it , will take pics of the back. When MPD cast them they had a pretty good foundry set up..

that'd be great!
I'll have to make the next set and just reinforce front face tab areas and try to make it look good.
since I don't have a 750 I would have to source out to someone who commutes a lot to try them out.
This would be the dream
having a small business just making these single aluminum parts on a large enough platform.
wonder what it would take to get the ball rolling?

wolf550 · « **Reply #9 on:** August 16, 2020, 02:57:29 PM »

you can see from the inside the prongs have cast nicely to pass through the rubber grommets.
Since these are heavy it would be good to have some sort of locking nut to make sure they don't go flying off for whatever reason.
It could be the open bolt with a nut screwed on or just the bolt with a lock washer.
for the next ones. I am going to extend the original prongs to allow the m6 die to add the nut at least and see how that does.

wolf550 · « **Reply #10 on:** August 19, 2020, 10:37:10 AM »

okay now I see where having extra holes comes in handy.
this next cast I extended the three prongs about double the length and with little shrink they are still longer.
as you can see there was still some nagative space that did not get filled in.
this was my bad.
on the two oil line arches, there is a big glob of aluminum at the two exits.
while boring out those two holes some area at the end becomes dislodged and bulges the outer sand.
when I wipe the excess sand away I check with my hand to see if that is still hanging on the mold but I didn't.
when I put the mold back down the sand started to fall into the cavity.
this made the area pretty thin at this area but it still cast the whole area.
time to clean this one up and see where its at.
the extended prongs might be the way to go for both sides.

wolf550 · « **Reply #11 on:** August 19, 2020, 10:38:42 AM »

one another note, I scored one of those sweet semitranslucent points covers from ebay.
don't know if its a frankenstuff or the other.
have to see if frankenstuff is making these again.

754 · « **Reply #12 on:** August 19, 2020, 12:05:22 PM »

You may be filling from the wrong side, I think the beauty side should be down and gravity will take care of good filling.
If you can get pegs like you have on the right side on the back of the cover, you could then finish them to hold the cover on , rather than adding pieces.

wolf550 · « **Reply #13 on:** August 19, 2020, 02:49:11 PM »

In the 550 side cover thread I mentioned that face down is the ideal way and is how the smaller covers are made.
the problem I was having in trying face down was the weight of the sand from the back side falling.
i tried this with a lip at the bottom of the inside mold. the inner middle would always fall through.

I don't know if there is a rebar like mesh material I should put halfway through to help reinforce it so it doesn't sink in due to weight.

Since these are different side covers it is certainly worth a try to give it another go and see what happens.

754 · « **Reply #14 on:** August 19, 2020, 03:29:28 PM »

Might be a sand curing oroblem.

wolf550 · « **Reply #15 on:** August 19, 2020, 07:15:58 PM »

yeah this green sand is somewhat more finicky than the petrabond sand.
still going to have to work it out and see.

wolf550 · « **Reply #16 on:** August 21, 2020, 07:21:10 PM »

Been moving right along with the oil tank side cover.
ground down the prongs to where they squeeze in tight and flush to the back of the cover.
there is about 1/4 inch sticking out after pushed in.
even though the prongs are straight I don't think I could use the die to cut out threads.

I remember seeing something like an alligator tab or the tab that you use on the emblems for the side covers.
or something as simple as drilling a hole to add a cotter pin maybe.

filled in those holes and with the complete oil line lip in the corner it looks good.

I think on the next one I'm going to smooth out the lines.

wolf550 · « **Reply #17 on:** August 22, 2020, 10:20:34 AM »

I did find a couple of pics of some 750 side covers.
the one from blog spot and the other from bill benton on here.
though the pics were the only two available I did see what my in between cast will look like.

wolf550 · « **Reply #18 on:** August 24, 2020, 08:30:53 PM »

this time on the left side cover I went a little different in my approach for the mold
using plastic side covers it wouldn't be good to fill sand, place cover and dance on it so I have been filling up then flipping on the mold.
this would always leave those unfilled portions on the inside creating cracks/ craters that I would smooth out to some extent.
on this one I kept filling from the opening making sure to pack it tight.
upon lifting I could see a smooth inner mold.
I think once I buy the side covers that don't have the emblems they should give the aluminum better flow to all areas.

I see a guy up in Los Angeles that has a frame on Ebay for sale. Have to wait and see.

after each one of these I make I always see that old lady from Beetlejuice saying "not bad... not bad..."

754 · « **Reply #19 on:** August 24, 2020, 10:22:28 PM »

I been thinking.. there must be some casting forums, that may be if some help ?
I mean, it looks like you are 90 per cent on your way, just need a bit more info..or a new trick or two.
A few more eyes on it won't hurt.l

Old Moe Toe · « **Reply #20 on:** August 24, 2020, 11:57:53 PM »

Using the lost wax method of casting would give you a much better finish than sand if you must make them in alloy.

wolf550 · « **Reply #21 on:** August 25, 2020, 03:52:48 PM »

I really like that die cast method.
Ive been seeing a lost PLA method but only with smaller pieces probably the size of those 350f covers.

since these came out good Im going to finish them up, get them smooth on both sides and see how they do to make some molds.

wolf550 · « **Reply #22 on:** August 29, 2020, 09:07:17 PM »

got around to picking up a frame and getting that left side cover to fit.
since it has the rectangle tabs up top I will probably drill some holes to have a safety wire attach.
now I have to see how these will cast.
already made a 750 points cover but with a different emblem.
this one fits so much nicer.

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Author Topic: CB750 side covers build? (Read 1832 times)