Honda CB750 Sandcast
The Restoration Shop => Paint - Badges and Component Refinishing => Topic started by: benjixt on March 09, 2012, 06:03:43 pm
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hello
The original top air box of my candy blue green has cracks (typical on this parts)
the price for a nos top air box or a used in correct shape is too expensive for me in the moment ( we offer me on ebay around 500 or 600 us dollars)
my bike is an early diecast and i'm not intersting in the 2 holes yamiya air box
i've see that LPM and david silver spares sold repro of the air box
i've got some question about it
do you think that this 2 shops got the same supplier or is it differents ( if it's different what is the best)
in your opinion what do you think about this repro parts ( 100% matching with the original) if there is differences what is it?
my original air box bottom lower is really perfect and i'd like keep it on my bike
can i put the repro top air box on my original air box bottom????
thank-you very much for your help
Benji
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BENJI
I have had good luck repairing sidecovers & airboxes with this stuff. It cures in minutes & when cured it is amazingly close to the original offwhite / cream color
http://kwikpolyllc.com/ (http://kwikpolyllc.com/)
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I've used DSS repro airboxes w/ no fitment problems.
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I think that a mix (DDS top/ original bottom) is not possible.
because the rail of the top DDS does not kiss perfectly with the original bottom, one of two is narrow.
I did this experience in the past, but you can try with better results of mine.
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I agree with Riccardo. I believe the reproduction molds were probably made using original parts so the copies would be slightly different. If I'm not mistaken I think Wayne was looking into this too.
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Yes Mark I sure did and will be selling my LPM box.
Benji
Riccardo is correct. The LPM pieces do not line up with OEM air boxes. (see pic) I thought I could use the centre piece but no go. I'm going to sell my LPM box and get the new 2 hole Yamiya. (wish they came out earlier).
As for repairing the box I did some research and consulted with various people and concluded that the best product to repair a box was with ABS as the box itself is ABS. Plumbers use ABS cement (abs and acetone) to join the connections in ABS pipe. It melts the joint and bonds almost instantly. So here's what I did.
After a bit of experimenting with old side cover pieces etc. I wasn't very happy with the outcome. I needed a lower tab for an original side cover so I bought a set of Yamiya re-pops. The right side cover is going to be the donor for the lower tab and some of the rest is going to the repair of my air box. I just cut it up into small pieces and let it soak in a clean metal can with acetone until it melts. I mixed it thoroughly and diluted it to the consistency of white glue. (Used by carpenters etc)
Next I prep the areas to be repaired. If it's a crack, drill a small hole at each end of the crack to stop it from "running" after the repair. Now grind material out along the crack with a dremel or similar tool. Do this both on the outside and inside of the cover. This will make the repair much stronger. Take a small paint brush and load it with your ABS acetone mix. This part you have to get the hang of. "Flow" the ABS mix into the crack. Go slowly. Too much and you will melt through. Too little it dries fast and you can't work with it. It takes a bit of time to get the hang of it. I had nothing to lose. Once my box was stripped I found the the damage was severe and what I thought would be impossible to repair. I was encouraged by the guru’s on this site to preserve every original part if possible, so that’s what I’m doing. It may never get used but it will shine a nice Candy Apple Red. :)
Once your rough repair is complete, shaped and sanded the next thing you can do is to smooth and fill areas with the abs mix. Just dilute the mix a bit more and brush it on like paint. Be careful not to melt through! You have to be patient! Once your bad areas are built up you are ready for final prep and paint just as you would with any other ABS piece. No fillers, no foreign materials. :)
Attached pic’s of what I thought was a pretty good 2 hole box when I got 576. A different story when I stripped it! The other pic’s show the missing pieces. (They had filled the box with fiberglass and bondo) and a bit of my repair thus far. Good luck!
In the last pic you can see the relieved areas along cracks still to be repaied. The repairs are still in the rough. I put this on the back burner for now. I'll post pic's of the finished box. :)
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Wayne, that has to be the best repair of that old material i've ever seen ! GREAT JOB !
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Thanks Steve. It was a challenge and a bit of a learning experience. The end result is very strong and I like that I can coat over the thin areas that someone previously sanded with my abs acetone mix and build it up to the proper thickness. The other end was actually worse and I didn't have a piece to graft into the corner so I had to shape it out of the ABS material I had. Much to my dismay the repair is so far, so good! I need a good centre piece so I can do my final shaping around the lip. I have one here but it's broken in half and missing pieces. If the Yamiya unit is close to the OEM spec I'll be able to model off of it when I buy one.
Just for clarification on my pic's.
Pic 1 is showing the "loose" fit of the LPM center in a bottom half. It won't work unless you reshape it.
Pic 2 is my original top half marked where I thought it would require repair. Boy, was I wrong!! :o
Pic 3 shows the piece that literally fell out as it was just in there with bondo and fiberglass. What you can't see are the other cracks and relief holes I drilled along with the grooves I cut along the cracks.
Pic 4 shows the corner filled and smoothed to perhaps 80%.The yellowish shiny spots are actually low spots along the face of the box that require more fill and sanding.
Pic 5 shows the corner repaired again, and partial repair at other end. You can see the grooves cut along the cracks ready for my ABS filler material.
Sorry for the out of focus pic's. Got a new camera for Christmas. Hopefully future photo's will be better.
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thank for your help
i'll keep my original andtrying to repair it