Rotary Shifter Go Kart build starts now!
In this video we rebuild our ultra rare 1975 KC27 rotary motor found in the Hercules W2000 Motorcycle. This is a 5 speed 294cc rotary motor with close to 30 bhp. In order to get it running, we had to completely disassemble the motor and take apart the entire rotor assembly to rebuild the rotary motor. This rotary go cart uses an engine similar to the artic cat 303cc rotary snow mobile so we think that we are going to be able to buy side seals from that to get this thing running. This is going to be one cool shifter go kart build! When rebuilding this Sach's Wankel motor for this shifter kart we had to soak it in Metal Rescue for a few days as well as break out all of the embedded side seals. After the rotor was disassembled we put in some brand new OEM Sachs side seals and then installed the rotor into the housing and torqued down the casing. The rebuild seems to have gone super good!
Stay tuned for the next video of this thing where we get this thing running!
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Here's the best part of building a rotary, the first company that ever sponsor that's actually someone called metal rescue, and then we have this, concentrate that we're gon na soak this rotor and we're gon na see how well it works. Take this rust off all right. Well there it sits it, don't fools. You see the water that's kind of before we can clean over here and rust after a lot of trouble, a lot of soaking this thing, a lot of chipping away as side Steel's.

We finally have a clean rotor. We use some of that metal, rescue, stuff and soaked it in it, and it looks great - and we also did a lot of chipping away at this. It really sucked, but alright, looks like our materials are really good. We're gon na do a little bit of sanding here, though, because the metal rescue left like a little bit of like a protective coating which is fine for storage, and so it's kind of four knocks to get into these.

But here they are look at these German parts. Oh my gosh holy cow, okay. These are so hard to find. I mean I I was looking on German websites and all this stuff and thank god this guy makes these Reaper or sells these original parts.

That's perfect! They're little rusty, they should be trimmed, they need. You turn lengthwise, that's it. Let me go it on the easy, better size Roger. These are perfect, they're, actually perfect dang and they almost fit like exactly yeah shaving down.

We need, like thousand seven inch clearance. I don't want to push them in all the way, so there's no spring in there, but yeah okay, well we're about to go back to college, but in the meantime I just sit on this stuff and next clip will be hopefully reassembling this entire engine, alright guys It is finally time we have all the pieces for the rotary engine. I did a bunch of research files back at school. I found some assembly manuals.

I found. I mean I really just want on rotary forums and see what like people do if they're rebuilding like an rx-7 engine, or something like that, so we are ready to attack this this this that in the Sun, these Springs we're so hard to find. These are the original Springs, we're keeping we're using the old, a Pepsi, those and all of that stuff. We're using this side corner seals, reusing one of the side seals, because these are the last five.

I couldn't even get my hands on a really good beside house. These are noise they're little scraps. There are some slight scores, there's a spot here where the rotor was sitting. They look really good same goes for over here, so we had this sitting in rust, remover for a really long time and it kind of left a little like protective coating, which is really great for it sitting in our garage.

But now we kind of need to get all this off and then there's a little bit of rust around here. So we have a super fine grit sandpaper, alright, guys so keep in mind that this is thousand grit sandpaper, and this is not a mating surface really. We should put this in a mill and have a read machine, but we have we have almost. We have over 1500 dollars into this engine already, so we're sanding it with a block.
It shouldn't be that big of a deal we're using thousand grit all we're doing is taking down the protector going to where we can see metal throughout. They will be good, so this side is all sanded, it's very smooth to touch and then bouncing light off of it. There's no visible or imperfection you can feel so we have our German parts here, the side seals and this one already rip in it. So I'm not gon na open the bag, but so basically we have everything laid out here, ready to be installed into the rotor, which is all cleaned up.

We have all the springs for everything they pick. Seals are pretty clean. There they're not showing any like serious signs of wear. They just have some slight pitting on them and nothing too bad they're, very smooth to the touch our rotors really clean.

We have our bearing that goes on the extension eccentric shaft in so now. We're gon na use some vaseline and just get all of this all done up. Ok, guys get in the spring in there and then now time for the seal and it springs pretty good awesome. Well, it's like a real rotary motor.

How about that? Never thought! I'd see that again, so now we'll just go kind of in-depth on this hike. I'm sure a lot of you guys are interested, but each corner seal has two Springs: okay, that Springs very nice, so now I'll put the other one in wow. This is beautiful, I'm so happy right now, y'all, you guys, don't know how much we've been like looking for parts on this thing, which time has been into this bill now, it's finally, all coming together nicely. It's really a thing of beauty.

Now we just hope and pray that this thing runs, because if it doesn't, I'm going to be very upset installing the last side seal right now it just goes in real nice everything's stringing up really good movement is slightly limited because there are gobs and gobs of Vaseline on this thing, but that's what the Gro turi guys use, so it doesn't hurt and it kind of makes a lot of smoke when it burns. Apparently so that's always fun sweet. So the apex seals are split into two halves. So when you're assembling it into the rotor housing, you put the little side in first.

That way it lines up all these Springs and stuff, and then we're gon na put it into the eccentric shaft. And then we can just install the springs and the rest of the apex seals all right guys moment of truth. We are bolting, the rotor housings together good thing all ready to go here, the rotors all assembled. So the manual said we need have the eccentric.

Shaft pointed down, and then we put the point of the rotor towards the spark plug hole. So so we got the bottoms of the apex eels in and then the Vaseline is holding those, so they don't fall out. While we hold this upside down. Oh there we go it there, we go rotors in that's badass, okay, cool.
So now all we need to do is we need to install the apex seals and the springs. So here the apex seal Springs and then they there's this little notch on the apex seals and then this just sits in there and then the smaller side, that's already in there has the same notch. So all we got to do. Is you put it so that that kind of? U is facing outwards and then we got ta make sure this is resting on the notch of the bottom part of the seal? Well, it's in Nice, okay, cool yeah.

You can kind of we can kind of tell because push it all the way in and then, when you spring it, it does not come like out all the way. So that should be perfect and then now we'll just put the top half in here's. The best part of building a rotary - this is the stuff on the floor right here I mean just it's you going into this. We have no idea what's going on Rory's or anything like that, we did the homework and it's all coming together.

Very well I mean so now all we need to do so. I'm just letting you guys get one last look at this thing for we seal it up for good. I want to keep looking at because this is so cool, so we'll seal up the other side of the case and then ten we're torquing down the bolts around the casing and that's gon na be kind of sketchy, but hopefully all go as well. And these bullets are pretty strong, so, let's put the other side.

Okay, guys say goodbye is the last look at this beautiful rotor. We go make sure the outside. Oh yeah, we got a couple of dowel pins. There we go.

That's good together. Nicely sounds: sweet, hey guys, so we got this extra long bolts here, so Jason, just getting there slow down that way to hold them in then we got all these other hardware. Here, that's ready to be installed so cue, the time-lapse. Those reading on the bolts in here it's gon na be fun.

Hopefully us not throwing fork wrenches, okay, that is six foot pounds. It's all torqued up, every single ball baby. Okay, so we got the spark plug in it now and, let's see if it makes noises yeah feels alright, there's not like a ton, but also it's a rotary. So it's not gon na have huge progression of the way yeah.

That's promising, though, that faster we tax a lot of noise, okay, cool all right guys. A long time ago, we took the transmission off of this thing. So now we got to put the flywheel everything back onto this bad boy, starter, she's, thinking about it and before we like do too much work and put all the transmission stuff on we're. Actually gon na try to get it running with the electric starter, and this will fly with here, so we're not gon na put the transmission on just yet we're gon na try to get it running first.

That way, we're not kind of wasting our time, but there's a little flywheel. So all this really is there's an adapter for the transmission as well as something that holds the starter, and so it really just kind of lines up through these downs and there's only like four bolts that hold this thing in pretty small. But oh and then we got these two here along with the two starter bolts and then I'll just cut a head and then there's this, which is basically the pinion gear that goes into the into the transmission and that slides on here then there's a washer! You bend up kind of like it just like to keep the nut on and then the nut goes there so we'll get that all assembled. But so far this thing is looking super good okay.
So it's a little makeshift and not super beautiful, but we made this real strong amount for this, so it would be super easy too. Unfortunately, we did not get the starter working. Just I don't know we're not really sure what's wrong with it yeah. I don't think I'll ever work, but we will be able to both with the transmission and kick started with this mount so I'll be super convenient there.

We go final touches before I really start cranking. This thing up this side cover this kinda just add: support to the two shafts that come up here, protect that clutch gears and all that ring back in I mean this engine looks so nice. We still need to throw the front cover on it and stuff, but I this thing is doing really well, arguably, the best part I've got a beautiful fan cover hey, this seems complete, looks like an engine again guys got this nice little stand for it. It's actually made out of bits of obviously wool cage, so it's pretty much good to go.

This is a long, video and there's a lot going into it so far. So basically, what I'm going to do is this is going to conclude part two of the rotary rebuild and then what we can do is just the next part is going to be just us working on it doing wiring trying to get the ignition system going trying To get a fuel system going and then just firing this thing up for the first time fingers crossed, although I'm not posting these videos, if we don't get it running so stay tuned for part, three.

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By YTB

30 thoughts on “Ultra rare rotary engine rebuild rotary shifter go kart build part 2”
  1. Avataaar/Circle Created with python_avatars Camel Garage says:

    A quote from Richard and precision transmission on YouTube scotch bright is your friend. It does great at getting surface stuff off the metal. Really enjoying the series so far man!

  2. Avataaar/Circle Created with python_avatars Marcelino486 says:

    Good morning, my name is Marcelino, I live in Brazil, I have a project for a rotary engine, 4 stroke, more efficient, smaller, lighter, without leaks, few moving parts, without valves; I need help to build a prototype. Do you know who can help me?

  3. Avataaar/Circle Created with python_avatars Jim Ciancio says:

    Tonight I was so very fortunate guy's! I was able to pick up a both running set of Wankels! A model Curtiss Wright Sachs 1-18.5 which is a 72 makes 19HP supposedly and the bonus was a complete and should be running KM-24 Sachs either a 1973 or 4 makes around 23HP both were complete air filters to exhaust and have decent feeling compression especially being dry and sitting around so many years. Thanks for the instructional video my friend! Much appreciated this helpful guide into the guts of the Spinning Doritos!

  4. Avataaar/Circle Created with python_avatars José Veinte Genario -NISU says:

    Aixro side seals and springs fit all Sachs Wankel engines (KM-37; KM-48; KM-914; KM-24; KC-27) Apex seals differ in lenght, the longest being the KM-914; if you have an acquaintance with a Laser cutter, you can try it in other dimensions. Yours is a KC-27, no need of a working depression capsule for many applications. (Wankel Club). Blessings +

  5. Avataaar/Circle Created with python_avatars Trent Buescher says:

    You guys gotta get a ultra sonic cleaner for all the rust you deal with. They are very cost effective and won't bust the bank.

  6. Avataaar/Circle Created with python_avatars Chad Chaddington says:

    I'm a sophomore in a local tech school in precision machine I could mill the surfaces of that rotar for like ten bucks lol

  7. Avataaar/Circle Created with python_avatars Shifttube says:

    yall sure that vaseline is heat tested lolol just never seen it done with vasaline b4 always assembly grease but it prb. samething

  8. Avataaar/Circle Created with python_avatars Shifttube says:

    just make sure yall blow out the place where the seals go after yall sand so they fit right

  9. Avataaar/Circle Created with python_avatars Steven Walker says:

    no sealer or gaskets on those block sections? Just curious..i've never worked on one..

  10. Avataaar/Circle Created with python_avatars Jose G A says:

    The rear side of the Rotor of this Sachs Wankel RCE overheated in the Hercules W-2000. If you manage to revert the mix flow, making it entering from the rear plate, and having some type of mix cooling after passing through rotor, as Norton did placing the carb after rotor was cooled, this will improve power and fuel efficiency. Perhaps this may result in engine turning the reverse way, but for some applications this won't be a problem. A simple measure for better performance is a Reed-Valve of adequate size, placed in the duct entering the intake plate, Homelite had some fitting. Please don't forget the 294 cc of Sachs Wankel working chamber is filled in 270º of shaft turn, much slower than in a reciprocating engine for same volume. Good time! Salut +

  11. Avataaar/Circle Created with python_avatars ephenj says:

    Any update on you guys getting it to fire? really would be a super cool build. I've seen the sachs 303's in go karts and then theres that crazy axiro xr50 that makes 50 hp for race karts, but being able to shift to would be epic.

  12. Avataaar/Circle Created with python_avatars Hugo B. says:

    i usually hate these "diy-build-gokart-high-school-hooningan-channels" but the fact that you are not making yourselves look like experts on a subject you are not, and the fact you are showing it on camera, and being humble etc…together with this amazing engine made like like this video series very much. thank you and good luck with the engine

  13. Avataaar/Circle Created with python_avatars Tim M. says:

    Are there not any gaskets for this engine case? I didn't see any.

  14. Avataaar/Circle Created with python_avatars Scooter Tramp says:

    Again, amateurs. If you must sand a surface, you don't use a sanding block .You affix a sheet of sand paper to a flat surface like a pane of glass and then rub the part over the sand paper if you want it to stay reasonably flat. I notice that you did not use any kind of sealer between the mating surfaces. These engines should have a thin set sealer like Threebond 1184 which remains flexible. Without a sealer, there is a good chance of some leakage between the surfaces and the subsequent erosion ruining the faces. No sign of any proper assembly lube either. This is a two stroke motor. Coating things with grease is not a great idea as it will prevent lubricating oil from reaching those surfaces requiring lubrication in a timely manner. On bearing surfaces, grease migrates to the outside circumference and then acts as a seal until it finally burns off. The bearings were designed for an oil mist which the grease effectively prevents. 5 to 6 thousand RPM with no lube. Do you see a problem here?

  15. Avataaar/Circle Created with python_avatars Curtis Tarwater says:

    Yeah!!! Good job on continuing the build. There is no better satisfaction than hearing a new engine run for the very first time!
    .
    .
    Now I know why I like you guys… saw your wrist band. Class of '92 MEEN here 😀

  16. Avataaar/Circle Created with python_avatars Dávid Lupták says:

    Before you closed it you should have soak everything in oil because now it will be a dry start before oil gets on the rotor. You can pour some of it from exaust or intake now. GL guys, hope for smooth start

  17. Avataaar/Circle Created with python_avatars Bob Washere says:

    if you're going to hand machine with sandpaper you should use a sanding block that is flat (+/- 0.001")

  18. Avataaar/Circle Created with python_avatars toordog says:

    Damn I would have offered double what that engine is worth (800) until I saw you block sanding it….

  19. Avataaar/Circle Created with python_avatars the_eddies says:

    I really came here expecting to see 5 minutes of crap and to hate on two little snots for daring to feck up a rare engine. But all apologies. You guys are approaching this just like I would and have done your due diligence. So I am the old A hole for prejudging. Subbed and total respect for your work. If it will run, you will make it run. Good on you and look forward to seeing it run or not. Either way you made the effort and that is the best reward.

  20. Avataaar/Circle Created with python_avatars Mike Moore says:

    As Elmer Fudd would say, " Be vewy vewy careful with those seals".

  21. Avataaar/Circle Created with python_avatars Michigan Engineer says:

    One of the nicest things about rotary rebuilds, especially older engines like this one, is there are so FEW moving parts to worry about! Plus if it does run properly again, you're going to have one hell of a fast kart for the displacement class.

  22. Avataaar/Circle Created with python_avatars zxggwrt says:

    Hey is there something like Metal Rescue™ for aluminum? Can you use it on aluminum? I have some corroded aluminum engine parts

  23. Avataaar/Circle Created with python_avatars Rui Kazane says:

    If that won't start, then you only have the rotor as the problem. Lucky! Think about piston engines. Valves, pistons and such…

  24. Avataaar/Circle Created with python_avatars styledliving says:

    probably would've been easier to lap it with a sheet of glass.

  25. Avataaar/Circle Created with python_avatars Victory First says:

    Tip two for you. When you need to just polish off a few ten thousands of an inch place the sand paper on surface plate or a piece of glass pane works also. You will be glad you did. Keep up the great work. Good luck too.

  26. Avataaar/Circle Created with python_avatars Matthew Vogt says:

    Got to love this video hey here's this engine we know nothing about that Parts aren't available for that we're going to do our best to make run. Thank you thumbs up

  27. Avataaar/Circle Created with python_avatars spacebike says:

    great video. don't use your hands as hammers you'll regret it when your older.

  28. Avataaar/Circle Created with python_avatars Tooextrememx says:

    alot of people remove the oil injecter and block it off and du a 2 stroke premix do some research into that as oil injectors clog and fail often.

  29. Avataaar/Circle Created with python_avatars Russell Booth says:

    I hope you work out the fuel & ignition system out,on some engines, it's difficult because I rebuilt a 2 stroke Stihl engine & it wouldn't start even with a new ignition coil & it had spark, the old one didn't.

    It turns out that the crankshafts were changed in the same model of engine, the keyway was milled in a different spot so the coil was actually different, so there's 2 coils available for different serial number engines.

    Since the ignition timing is fixed,the coils dwell must be set differently in the electronic module (i.e. to fire at a different time).

  30. Avataaar/Circle Created with python_avatars ssplintergirl says:

    Good luck in college.

    I am an aero engineer and boy is it something.

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