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Author Topic: saving a 1980 KZ750 twin  (Read 62183 times)

Offline doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #250 on: Jan 29, 2017, 03:34:22 »
i like shiney

Offline JadusMotorcycleParts

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Re: saving a 1980 KZ750 twin
« Reply #251 on: Jan 29, 2017, 07:27:05 »
Whoa man, this is next level shit.  Really inspiring stuff!  They came out great :)

Offline pacomotorstuff

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Re: saving a 1980 KZ750 twin
« Reply #252 on: Jan 29, 2017, 08:46:58 »
Hi Doc,
Nice investment casting - the oldest casting method known to mankind and still a great way to make parts.  Something you learned in your day job (you're a dentist, right)?  I have a couple of places in my town that do it, but I've never approached them about doing some one-offs or small runs.
Neat 3D modelling - I should really get into it, but I'm from the old school of patternmaking (learned it 35+ years ago when I was working my way through school), where you make the master by hand on the bench, figure out the shrink allowance and adjust the pattern to suit.  Wow, how much easier would it be to push the button on the keyboard to make the pattern a little bigger and then CNC the master?
Looks like a pretty big riser for the part (a lot of metal left in it after chilling) - but too much is better than too little, right - and the foundry just remelts the offcuts anyway?  Also wondered why your foundry didn't suggest using a gating system and pour a number of parts at one time?
I gather it's A356 aluminum alloy - seems to be the bread and butter casting alloy in these parts and the finished product doesn't seem to exhibit any of the issues of a casting with a lot of reclaim in it?
BTW, the above are not criticisms, just questions - there are many, many ways to accomplish the task and... I was just curious.
Your attention to detail is awesome , incredible, inspirational - maybe just the thing to shake a lot of us out of our winter lethargy, up here in the frozen north.
Most excellent build.
Pat

Offline Nebr_Rex

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Re: saving a 1980 KZ750 twin
« Reply #253 on: Jan 29, 2017, 09:36:20 »
Would you consider casting up some more for sale?
The KZ400/440 use the same cover. :D


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Offline Green199

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Re: saving a 1980 KZ750 twin
« Reply #254 on: Jan 29, 2017, 09:43:19 »
God damn, this may be one of my favourite builds on this site. Love the fabrication work you've put in and the cast covers turned out very nice.

Looking forward to seeing a pic with the bodywork back on the bike, but damn, it looked good in satin black!  :-X
1973 CB250 'Doing it right this time round' - http://www.dotheton.com/forum/index.php?topic=36795.0

Offline Tune-A-Fishİ

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Re: saving a 1980 KZ750 twin
« Reply #255 on: Jan 29, 2017, 10:01:09 »
Namaste  :o
"I didn't come here and I ain't leavin"  Willie Nelson

"love hard, live fast, die fun" Kacey Musgraves

"Like a Wreckin Ball!" Eric Church

Offline canyoncarver

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Re: saving a 1980 KZ750 twin
« Reply #256 on: Jan 29, 2017, 15:33:36 »
Outstanding work Doc!  They really came out nice.
--

YZF750/1000R The Fly
KZ 750 Twin
ZRX 1100
KZ400 The Rabbit
KLR650, 65 Norton, my never finished shovelhead chopper, an 86' FXR, and an F9 Bighorn
more YZF750R's, more KZ's, a Zephyr750...and the ever unfinished 75' CB550 cafe.
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Offline teazer

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Re: saving a 1980 KZ750 twin
« Reply #257 on: Jan 29, 2017, 17:17:49 »
Talk about raising the bar.  Nice work.  Color me impressed.

Offline doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #258 on: Jan 29, 2017, 18:13:58 »
Thanks guys. Just having fun.


Hi Doc,
Nice investment casting - the oldest casting method known to mankind and still a great way to make parts.  Something you learned in your day job (you're a dentist, right)? 
Hahaha. I'm no dentist, or even a real doctor. just a nickname that stuck from highschool.

Wow, how much easier would it be to push the button on the keyboard to make the pattern a little bigger and then CNC the master?

Yeah it takes about 5 seconds to scale something in Rhino. Heres the 3-d printed master that I took a mold off of, and the original badge I based it off of.




Looks like a pretty big riser for the part (a lot of metal left in it after chilling) - but too much is better than too little, right - and the foundry just remelts the offcuts anyway?  Also wondered why your foundry didn't suggest using a gating system and pour a number of parts at one time?
I gather it's A356 aluminum alloy - seems to be the bread and butter casting alloy in these parts and the finished product doesn't seem to exhibit any of the issues of a casting with a lot of reclaim in it?

The foundry I have access to is operated by the sculpture department at my college. As a grad student I get a pass to do pretty much anything I want; interlope into other programs and departments. Its awesome. That being said, this foundry pours metal maybe 6 times a year for the sculpture students so there is a VERY loose/crude process established here.  Typically sculpture doesn't need to "work" so a lot of things that would make castings unacceptable for industry use are widely tolerated here. I blew their minds when I showed them how to do a "face coat" with chopped fiberglass in the investment. That should inform you to the caliber of work they are turning out. I asked for their advice on gating and started talking details and got blank stares in return; its something I know little about, them as well. I did one cover per investment to keep the investments physically smaller. I have only done the plaster/silica investment once before, the other times I had access to ceramic slurry investment which is much better IMHO. The castings moved around a bit and there is porosity throughout. Its not too noticeable unless you inspect close up. I would not expect them to hold oil but its for the ignition cover so its good enough.



« Last Edit: Jan 29, 2017, 18:37:06 by doc_rot »

Offline Eleganten

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Re: saving a 1980 KZ750 twin
« Reply #259 on: Jan 29, 2017, 18:25:24 »
Looks really good!


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