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Author Topic: EFI Bighorn  (Read 30139 times)

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Offline Uniflow

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EFI Bighorn
« Reply #60 on: December 12, 2012, 10:42:42 PM »
Well, second part to the " don't use that bloody furnace again " was we had an explosion while tipping excess alloy into a pot on the ground. There was a little dampness in the pot. NEVER tip molten alloy into a wet pot!!! The alloy went straight up into the air, must have gone quite high as it took a while to rain down again. My mate ran into the shed while I ran out into the paddock ( being NZ it was with the sheep ) > The alloy was still quite hot and I got  burnt in the hair and down one boot. Unfortunately  the wife saw it all and along with the crack in the crucible       that was the end of that!! No sheep caught fire.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline _X_

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« Reply #61 on: December 12, 2012, 11:03:08 PM »
wow scary moments there uniflow. thats were i was going jeram. HA! amazing stuff you do uniflow.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Jeram

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EFI Bighorn
« Reply #62 on: December 13, 2012, 02:31:06 AM »
nice, by the look of it that one is a cylinder reed yes?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline factoryX

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EFI Bighorn
« Reply #63 on: December 13, 2012, 04:35:59 AM »
Quote from: Uniflow on December 12, 2012, 04:19:41 PM
Casting, pattern making and machining are my hobby and job. So if I get a little carried away just say so. To cast a twostroke cylinder first you need cores then a pattern. I make my cores often with a rubber mold of a cylinder I like the port shape of, then copy into a two pot casting resin. So you end up with ( male ) transfer port shapes like this.


Then these need to be copied back into a core box, so you can make more of them ( in casting resin for the cylinder pattern itself ) and ultimately these boxes will make the hard sand cores you cast with. Basically you manufacture the cores first ( in casting resin ) stick them all together, then add thickness on top of that.





This is the pattern being made up of the resin core prints. What is solid here will be holes in the casting ( when done in sand ).




This is the main cylinder and exhaust port as one core, here is the box it's made in.




Here is the pattern made with all the smaller cores glued inside. You can see the core prints ( tapered bits on the ends) sticking out. This gets invested into sand then removed. While the sand mold is apart, hard sand cores are fitted ( transfers / water gallery etc ) They will fit neatly into the core prints provided by the mold as it was invested. With the mold back together and cores in place, metal is poured in. Where there is sand ( as in a core ) there will be a hole ( port ).
Thought I had some pictures of the sand mold set up and pouring, but must have deleted them?
I have others but not of twostroke parts.

So badass I nearly fell out of my chair haha
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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I ride an 03 yz250, wait 04, wait 05, what ever, they're all the same #$@% YOU!

Offline Uniflow

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EFI Bighorn
« Reply #64 on: December 13, 2012, 04:41:04 AM »
Yes Jeram it was a reed cylinder. I'm only interested in rotary valve engines.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Jeram

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EFI Bighorn
« Reply #65 on: December 13, 2012, 05:34:30 AM »
Would it suprise you that Im out in the shed measuring all my motors to see if your disc valve cylinder will fit my bikes ? haha
(the answer is yes)

Id love to be able to take a few days of work some time to fly over to you and see you do this whole process from start to finish. it seems like a VERY handy skill set to have!





« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline TMKIWI

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EFI Bighorn
« Reply #66 on: December 13, 2012, 06:42:12 AM »
Quote from: Jeram on December 13, 2012, 06:34:04 AM
were you hoping we could call him Aluminium-Member? LOL

He does look a little like the man in question. Only taller. ;)
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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If you don't fall off you are not going hard enough

Offline Uniflow

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EFI Bighorn
« Reply #67 on: December 13, 2012, 07:21:45 AM »
I worked with a skilled pattern maker a few years back. We were making after market Subaru EA 81 pushrod heads then, heads with four ports instead of two and other projects. Jeram, be my guest, I'm keen to get stuck into this new engine ( for the YZF frame ). Next time I'm casting (at the foundry)I'll post pictures.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline SachsGS

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EFI Bighorn
« Reply #68 on: December 13, 2012, 03:30:08 PM »
Rotary valves aren't always about going fast......

                                           www.retrotrials.com/mecatecno.html
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Uniflow

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« Reply #69 on: December 13, 2012, 09:18:33 PM »
My point exactly, with vairable   rotary valve housing, exhaust power valve, ignition timing and injection timing you can have the best of everything low end and top end.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline bearorso

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EFI Bighorn
« Reply #70 on: December 14, 2012, 05:08:21 PM »
Quote from: Uniflow on December 13, 2012, 06:42:42 AM
Well, second part to the " don't use that bloody furnace again " was we had an explosion while tipping excess alloy into a pot on the ground. There was a little dampness in the pot. NEVER tip molten alloy into a wet pot!!! The alloy went straight up into the air, must have gone quite high as it took a while to rain down again. My mate ran into the shed while I ran out into the paddock ( being NZ it was with the sheep ) > The alloy was still quite hot and I got  burnt in the hair and down one boot. Unfortunately  the wife saw it all and along with the crack in the crucible       that was the end of that!! No sheep caught fire.


This what happens when you mix business with pleasure, Uniflow!

When Will You Kiwis Ever Learn?

Keep your concubines away from you when you are working - too much of a distraction.

Their a Weird Mob in Un Zud, they have far to close a relationship with their Jumbucks!  :o

Sick Puppies, the lot of them. :-X
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline SachsGS

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EFI Bighorn
« Reply #71 on: December 15, 2012, 12:26:39 AM »
Has TMKIWI been hiding something? :<img src=" title="Roll Eyes" class="smiley">
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Uniflow

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EFI Bighorn
« Reply #72 on: December 15, 2012, 04:16:12 AM »



The ball throttle in place with TPS on the end. Nice big ( well 36mm anyway ) hole straight in. This is with the variable valve open. Try viewing your crank on a reed engine like this! This has got to work better than a slide? Nothing touches, ball valve runs on bearings. Next, see how it runs.
The map will have to be changed now, different airflow verses TPS positions.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Jeram

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EFI Bighorn
« Reply #73 on: December 15, 2012, 04:28:01 AM »
looks promising, how did you decide on the inner radius's of the ball (the bell mouth)?

there are some SAE papers which suggest that with some slight adjustments to the shape of your valve that you could gain some decent CFM improvements.

Mainly they just found the optimum radius compound curves and lengths for making HP. Its based on the bell mouth of a carb/throttle body but should be perfectly applicable to your application!

what you've got looks pretty darn close though, but it'd be interesting to measure how close it is to 'perfect'.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline Uniflow

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EFI Bighorn
« Reply #74 on: December 15, 2012, 05:07:55 AM »
Perfect, measure, what are these words??? Unfortunately I'm a bit " that looks about right " sometimes. It's a matter of what would fit / look right / what I know about 3D on the CNC ( not always enough ) and time. Hey it's a first up, lets see what happens?
The bighorn doesn't need more power, I just need to ride better but if more power is available, I'll take it!
You know, it's a trail bike, steel wheels, steel tank, steel guards and I'm not little. So if I've got a power advantage, good on me.
Sounds like I'm making excuses, I am.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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