Homemade Jet Drive 2 Stoke Twin Cylinder

Joining two 50cc pocket bike motors together to make a 100cc two stroke twin to power the homemade jet unit , made the expansion chambers off a measurements from this video • 2 stroke porting, part... . Follow on Facebook / dkthewelder
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[@homemade_madness]

Love it bro ive been following your channel for a while now and i think you and me need a chat soon as i need some of your jet building skills😜 will be doing something like this too soon🤟🏼

[@DktheWelder]

Thanks! I’m a big fan of your channel , I actually don’t really know what I’m doing with the jet units but think I’m on the right track. I am happy to help out any way I can 👍

[@supardin0073]

@@DktheWelder akm

[@remcovanvliet3018]

Colin Furze impersonation just about killed me mate it was so bloody spot on! 🤣

[@DktheWelder]

Thanks I glad someone got a laugh out of it

[@westie4ageturbo.749]

Colin furze would rate this for sure mate! 2 stroke stuffing would be interested as well I think it’s bloody interesting!

[@DktheWelder]

Thanks 👍 I watch both those guys!

[@MrJob91]

this video is total vodoo magic. The sound of these engines coupled together is like clockwork magic insanely good.

[@DktheWelder]

Haha it sounds pretty cool

[@markmaraman8858]

@@DktheWelder mgqgaVva qmam v

[@MsJon52]

talk about a timely vid, i have just bought one of these motors to build a very small inflatable boat motor so seeing them run on your vid is a bonus.

[@DktheWelder]

Cool mini inflatable boat sounds fun

[@davegibs4761]

Where can I get my hands on some little motors like these? Which website?

[@MsJon52]

@@davegibs4761 i got mine from ebay, £39.

[@SuperMatt6000]

Really like how this projects shaping up. Printing added another level to the awesomeness.

[@ats-3693]

That's awesome those motors sounded sweet running together, the Colin Furze imitation was pretty good too especially the rooting the engine on the bench bit, spot on! 👍

[@ryanperry9472]

This is so AWESOME!!!!!!!!!!!!! Great work! So happy you are using 2 strokes!

[@trklclark]

You rock DK. Love the plan, love your work - I'll keep watching for sure

[@natefessler3961]

Love the backyard engineering going on here. And the Colin Furze flailing montages, lol

[@militaryrig]

I partially designed a jet drive using a chainsaw engine with the intention to stick it on a board but never got around to making it. So this really floats my boat. I always was unsure what size chainsaw I would need with the size of impeller. Keep up the tinkering!

[@DktheWelder]

Chainsaw motors are pretty powerful I think you need at least 6-7 hp to get up , I have a big stihl chainsaw I but on a surface drive on my channel which was fast. Maybe an 80mm impeller would be enough? I hope you get to making it!

[@FAKE-NAME]

add a vertical trim nozzle to the jet. helps get on plane easier and if adjusted fully up it helps with rooster tail(everyone likes those)

[@grimfpv292]

I love this project! It's not far from what I'm planning out.

[@Only1Sethy]

Amazing content man, I'm now subbed, and can't wait to follow this series!

[@whirlybirdrc]

You did exactly what i was thinking about doing but i wasnt sure how to connect the both engines together. This looks simple this way you can use the stock ignitions on both engines Awesome video!

[@louismorgan2679]

This Is just awesome on so many levels, great work mate

[@nickthelebo]

They sound dope running together

[@glumpy10]

Impressive setup. They are going to scream pushing a board along at a great rate of knots.

[@DALapygin]

Some years ago i build something like this. Main trouble - synchronization of carburetors. I was weld Y shape collector with vibration damping inserts, and use one carburetor to supple fuel/air mixture to both engine.

[@DktheWelder]

That could be an idea, it is all very well running this on a bench but under load it could be a different story

[@DALapygin]

@@DktheWelder Three upgrade i recommend for this setup. First as i say - Y shape intake. Second: use soft coupling between engines. When i was buildet my device i use very hard rubber disk with four holes as coupling element and two disk with two cylindrical fingers as input and output. And three - i use ball shape joint to connect exhaust pipes. Also very important right setting of pistons before connecting engines. One must be at top position another on bottom. First time i missed that. And when my device start - i got jumping crazy frog :)

[@dallasstepto8409]

What an idea very clever mate can't wait for more of this build

[@DktheWelder]

Thanks. I’m glad it works, building the board will be fun

[@dallasstepto8409]

@@DktheWelder will be a handful

[@bluecookiemonster3]

If youtube was like the stock market, Id buy as much of your stock as possible man! You are gonna make it on here with these mad skills

[@SluSharkND]

You said "now is the cool part". Are you kidding? I'm a new sub, and so far everything I've seen is the cool part!

[@bossmanprezzie8923]

This is so sick! Love the Colin Furze bit as well.

[@DktheWelder]

Thanks 👍 Colin furze is the man haha

[@BruceLyeg]

This is pure coolness. It sounds so good too!

[@DktheWelder]

Thanks Bruce

[@markkeast6786]

Couldn't help but laugh at 8.35 when you tried to stop it running 1 engine at a time...😂

[@DktheWelder]

Haha I had to leave that in , it was a struggle to turn them off

[@thefinalkayakboss]

As a guy currently trying to make his kayak jet drive with a pair of chainsaw motors and RC boat jetdrives this is all priceless information

[@DktheWelder]

O cool! I am actually building a chainsaw powered longtail motor for a kayak sized boat at the moment. A few things to know though, a kayak isn’t a planning hull so will just plow water instead of getting up on top, and jet drives suck the power like they need double the power a prop does to go the same speed, really manoeuvrable though

[@thefinalkayakboss]

@@DktheWelder ive heard that about the problems with the hull shape, my plan is more or less to apply the power first, expect the boat to behave like it hates it, and start messing with strakes or maybe some sort of trim tab if i can keep it simple. I did not know that about the jet drives, its a good thing i havent made my final selection for a power unit. Thanks for the advice, and you do some fantastic work homie!

[@starlordd6408]

I love me a Colin Furzy Clone! You Rock Man! I look forward to your videos

[@DktheWelder]

Thanks! Colin furze is great haha

[@T74V1N]

My favourite kind of mad scientist!

[@DktheWelder]

Haha not much science, a lot of trial and error

[@fullsendmarinedarwin7244]

sounds killer!! I want to make a 2cyl now

[@tillymenzies243]

Not sure how I haven't stumbled across your videos until now, but you're balls deep into the kind of hare-brained nonsense I love. On a more serious note, the cylinders on those 2 engines you're using there probably have "boost ports" machined into the cylinder wall. These ports are a gimmick that the manufacturers are adding, and do nothing for performance as they are only 2mm deep. They do however cause severely accelerated piston wear because of the tiny amount of contact area left for the piston to run on. Replace them with the one piece cylinders and get the non-window pistons. Tune nice and rich and the one piece top ends will last waaaayyyy longer than they should. Wicked build!

[@marioncobretti7870]

Thays pretty cool. Sounds sweet.

[@aretardridesmotard6128]

Some clever people across the ditch. The fella who builds his own laser cutters comes to mind! And EZ jet of course

[@ebenwaterman5858]

There's tons of videos demonstrating how 3D printed stuff fails under load. And now leaks.Oh well. Experience is the best teacher. Subbing. :)

[@DktheWelder]

It isn’t the strongest way of making stuff but is good for some stuff

[@ebenwaterman5858]

@@DktheWelder Definitely. I like the way Rocket Lab 3D prints their rockets. ;)

[@iamkian]

Looking good. I love the nose of one single motor running but two is even better :-)

[@hamishmurray5540]

Brooo. Love it, please don’t make me wait a week to see part two

[@seditt5146]

You might not know this but this IS part two. Check the video right before this for part 1

[@DktheWelder]

Sorry I work full time and have kids and stuff, hopefully next week or the week after

[@hamishmurray5540]

Fair enough bro. Love your content man. I tried the same engine set up 2 years ago behind a 89 wave runner (wr500) jet unit, it didn’t go so well as i used the really cheap units that come on the common Chinese kids bikes.

[@aretardridesmotard6128]

Further fabrication is the name of old mate with the laser cutters. Cant wait to see this in the water.

[@andersson.l.e]

Thank you for an interesting video. I think you can use a 2 pole switch and connect the 2 ground cables together and the engine side separated. Keep up the good work.

[@toyoboi]

PLA does dissolve when in contact with with gasoline, just a warning about that T piece. This whole thing is badass

[@DktheWelder]

I was hoping to print a fuel tank but I don’t think that is going to work 👍

[@toyoboi]

@@DktheWelder look into PETG, it prints easy like pla and could be used for a gas tank. I've used PLA as motor mounts on a go-kart and they lasted a long time but showed signs of dissolving. So that's the only thing I'm basing my evidence on, you could print a test gas tank or drop a piece of a print in some gas and see how it fares. Good luck!

[@jyetraval6722]

I was thinking about doing pretty much the same thing, I’m so glad I found this video

[@DktheWelder]

It didn’t really work that well not enough power. Have you seen the test video?

[@jyetraval6722]

@@DktheWelder I wanted to use 4 ms290 chainsaw motors

[@Ben-Dixey]

Interesting project, the Colin furze part was great 😂. The expansion chambers look nice, it will be interesting to see the power increase, I've just gone through the same myself but I used all Aluminium and went through the AuMechanic's calculations, as you say it's a mission making two chambers. Subscribed to your channel, nice work and videos. 👍👍

[@littlelifters7543]

This is awesome. Could you make a common exhaust flange to help with stiffness between motors. Old bmx bikes had cable splitters for the rear brake at the headstock, maybe look at one of those for your throttles.

[@jakebarnhill6308]

I rate this man, keen to see how it turns out. PLA or PETG are the best materials to 3D print with, ABS is more problematic. You can turn up the ‘flow’ setting to get stronger/more waterproof prints, I would start with turning it to 104%

[@DktheWelder]

Ok thanks I think I will try that

[@AntiVaganza]

@@DktheWelder late to the party, but drop retractions, too if you can - they can leave leaky pin holes. As for PLA being "best", well if best = easiest, then yes. But not in terms of heat resistance or much else.

[@trevevns3242]

Loved the video killer all hail the mighty furze 👌👌👌

[@Order4627]

Great content, have subscribed.

[@agentcovert]

Great video..a bit late now but I've seen people make different complex items such as expansion chambers , muffler and even pulse jets using flat sheets welded together at the edges 100% then a pressure washer quick connector attached to it and basically inflate the 2d shape to 3d using water pressure rather quick and easy..depending on the shape some people add an extra area to be cut off later for the pressure washer connector..the water under pressure really makes smooth wrinkle free forms..

[@DktheWelder]

Hydro forming it’s very cool I have actually tried it before! It’s difficult not to get any creases and curves get distorted it’s ok for bigger stuff but I would mess it up I think

[@thebug4046]

Sounds good!

[@phildawe7172]

what a great project!! genius to couple 2 engines like that in a simple way. those motors have good bang for buck. stinger pipes are going to heat up without water exposure or good airflow ducted across em. im sure you'll make it work though can say your project even includes the kitchen sink! (beaut job of the stingers) I'd love a jet board but they are crazy expensive off the shelf compared to a jetski. keen for your next vid👍👍✌

[@DktheWelder]

I'm trying to build this board for under $1000 dollars I hope it works!

[@phildawe7172]

@@DktheWelder that's rad. I reckon you can do it! working out the hull/board will be interesting. fully manufactured from aluminium would be rad. or a hybrid foam/exo-fiberglassed shell with aluminium mounts for the engine and jet 🤔 also want the exhaust to not draw in water from backpressure. use whatever trick outboar motors use i guess. keep it up! :-)

[@rct2]

They sound efin awesome, Alan Milliard would be impressed.

[@DktheWelder]

Haha Allen Millard would have done a way better job!

[@nickpfohl1920]

Aaaaaaaaand Subscribed! Cheers from Canada 🇨🇦🤘🤙

[@kennethjohnson7893]

I gotta try this, I need to hear that sound in person

[@DktheWelder]

It does sound pretty cool in person

[@mitchellmanson449]

i modded a handful of these mitsu clones and would love a drive adapter to pair a few together, i have 3 modified with porting, electric start, and tuned pipes, my last prototype had a stuffed crank and pulse lines to run a weedwhacker style pulse carb, great for only idle and full wot! great video and impressive fab skills, i subbed!

[@nickbaddorf2673]

Loved the video! So cool! Where did you get these motors? PS. I thought I saw you using a raft when 3D printing, and if so, I would highly recommend a glass bed with hairspray. It is magic it works so well

[@rajgill7576]

7:39 colin furze hype montage?? Subbed hahaha

[@DktheWelder]

Haha yes ! And thanks

[@kennethperian4370]

Your doing great bro, wish my skills were close to what you can do. O well that’s life so keep up the good work and well see ya next time see ya bye bro.

[@tazyt3388]

awesome mate loved the colin montage those little donks will rip goodonya bro cheers

[@DktheWelder]

I hope so! If the expansion chambers are right it should do

[@tinkeringstuffs6542]

i dont know a lot about welding but ... i feel like weling a jacked will be kinda hard ... especially since its usally kinda hard to weld to motors like that ... so what if you take copper tubing which just fits inbetween the cooling fins and just kinda bend it around there have the water going though that... really cool projekt really looking forward to it

[@DktheWelder]

I did think about the copper pipe thing but I reckon I can weld a jacket on the cylinder. But I might wrap some copper pipe around the exhaust to try cool it down a bit

[@bluestripes1]

very cool project

[@bvr1962]

the second engine are you going to put a piece of metal in place of the shroud just wondering i would think it might heat up

[@chaoticslap7536]

For the off switch. To keep them seperate but switch simultaneously you need a 2 pole switch. 12v or 240v will work. Whatever you can get. Hope it helps

[@kurttaz]

So good 👍, keep at it man👊👊

[@devriesfabmachine8721]

Colin furze imitation was on point😂

[@padillaxA]

Idk if anyone else posted about it yet but you can run both kill wires together. Just put a switch inline and find a good place to ground.

[@dirtfootracing8788]

Always something new......

[@backyarddodgyness]

you need a Double Pole Single Throw (DPST) switch, normally used to switch both + and - off but you can hook each engine kill wire up separately

[@DktheWelder]

ok I will try find one thanks

[@pcparlor]

Glad I'm not the only one who tig welds with mig wire: )

[@DktheWelder]

It’s expensive to keep buying the proper stuff the mig wire is a bit annoying how it’s curved but not too bad aye haha

[@triggeredmonkey3439]

I'm really curious to know how long that little 3mm thick flywheel key is going to last.

[@298FAB]

Good work sir please do more she sounds like an old school plane 🫡🏴󠁧󠁢󠁥󠁮󠁧󠁿 god bless

[@DktheWelder]

Thanks 👍

[@gabbermaikel]

still a cool project. Hope the printed jets work out, would be cool.

[@usernamesaredifficult]

this is a bit of a late reply but will you be releasing the files for that engine coupler anywhere?

[@ss-sq1hn]

You should forget the water jacket. It will leak. Just make a heat plate from sheet metal and add 12v blower fan on it. it will be fine! It is nice to see this coupling worked so nicely. 😀 You can even use this flywheel as a blower. Just need to build a casing.

[@MultiBigDenis]

but will the plastic adapter withstand the work under load ...

[@Paulman50]

Cool, good to see some more kiwi stuff on here.

[@T____K]

casting an impeller might be a good idea, PC-ABS worked fine for me, though, annealing it is key ! ;)

[@DktheWelder]

Abs works better for impeller? Does it print the same?

[@T____K]

@@DktheWelder its a special ABS and Polycarbonate blend , its way easier to print , almost no warping and annealing the print at 150 °C is the way to get a real solid and sturdy print, you could probably print a blade for milling wood , using this stuff

[@T____K]

@@DktheWelder ABS might work as well, but I don't like printing ABS...

[@Iowa599]

Did you think of making the cylinders opposed, instead of inline? It should dampen vibrations, somewhat, since the pistons motions are *almost* (hence: somewhat) exactly opposite.

[@DktheWelder]

Maybe setup in a boxer setup would be best I think it would help with vibration

[@matexf]

Very entertaining thanks mate

[@jeroenjager]

Nice!

[@MrNotStock]

yeah boi so awesome

[@DktheWelder]

👍

[@pieterbarneveld9518]

Impressive

[@bigdaddy_TV]

Perfect very clever

[@DatBlueHusky]

make the engine mount more rigid, it may seem strong but its flexing like crazy and you cant see it. It will be way worse when there is a load as well. Best is either to make a top plate or use a thicker engine mount plate or steel

[@DktheWelder]

Ok I think you are right I will make an aluminium plate for the top need it more ridged

[@littlescoutfpv9776]

love your videos man! How many horses do they make?

[@DktheWelder]

I’m not sure . They are supposed to be high performance, maybe 4-5hp each they sound powerful haha

[@jordonwilson2259]

You willing to make and sell a little kit to link motors together?

[@jackrichards1863]

You sound a bit like a Kiwi brother? Those motors sound pretty mad, wrap them expansion chambers with some fireproof material to quiet them up a bit? Nozzle in grey looks pretty savvy! I like your experiment mate. might have to sub this one to keep up with the progress.

[@leomifsid]

That's sick Im a bit late to this video but hope you will reply just wondering if you have all the 3d printed parts STL files published some where or it I could get them somehow because I would really like to try this

[@leomifsid]

Nevermind I was interested and watched the whole series then i found link in description I bought the coupling $2!! thats so cheap can't wait to build my own inline 2 was just wondering what wall line count you used ?

[@DktheWelder]

I think I used 4 wall lines and printed it solid

[@petermines3575]

Master craftsman

[@SamSep01]

This is so freaking cool! Do you still remember what crankshaft angle you used when combining those 2 engines? It sounded so good!

[@DktheWelder]

They are at 180 degrees apart, it does sound awesome just not very powerful 👍

[@SamSep01]

@@DktheWelder Thank you. I'll be building my own! Twin 2 strokes are rare as heck, this is gone be fun!

[@user-mf5nc4ks2u]

Хорошая идея с водометом. Приятно смотреть на хорошую работу.

[@NaiyimsGarage]

I have question: in video [2.08 ] you marked the position of the piston #1 and #2 "one all the way up and one all the way down position" why is that? Would you please be so kind to explain to me? , Thank already give you Thump UP and Subscribed

[@DktheWelder]

I just wanted them to run opposed so it would run smoother

[@NaiyimsGarage]

@@DktheWelder ok, THK

[@cliffcampbell8827]

If you had the engines firing 180° out of sync, you should be able to "Y" the two exhaust pipes together and use the velocity of the exhaust from one engine to provide a low pressure vacuum to the other cylinder's exhaust effectively pulling the exhaust out...but that might pull too much out. Some of your air/fuel mix might go with the exhaust fumes, especially at higher rpm's. Then there would be the vibration issue. A twin firing 180° out of sync...you'd need a good vibration dampening device to keep the two motors from shaking themselves apart, particularly at the coupling.

[@DktheWelder]

I would like to do the two into one exhaust but I’m sure I would have to recalculate the shape?

[@tom5051666]

weld a piece of rod to the middle of your sheet. put in the lath, use a parting off tool to cut the hole.

[@CKILBY-zu7fq]

That's pretty damn cool. Yeah the motorbikes In America which is love to have this setup. And boy if you could just figure it out some more some of the motorcycles here might want one of these as well, I mean at least it sounds better than some of them I've heard. okay. Okay peace

[@DktheWelder]

Thanks it does sound cool , not much power unfortunately 👍

[@charlesyates6687]

These motors are made with cranks that are pressed together and held by friction . Combining two motors together will surely couse crank slippage and major bottom end malfunctions. Will not work or will not work for long unless both cranks sre either taken out and welded to be solid cranks . 5 peices are pressed together to make one crand they are not welded together so these press fited parts can and will slip .

[@DktheWelder]

Seems like themselves motors don’t have enough power to slip the cranks haha. I could just weld them together but was just so disappointed with the power from them

[@DANTHETUBEMAN]

What can you do with electric motor????

[@gonzore.5256]

That,s the! 2* 50 CC nice!.

[@fjb4750]

Can you tell us where you got the motors from? I’m looking for one to put in a 7.5’ RC Boat.

[@DktheWelder]

I got them off trademe a New Zealand site, but they would be on eBay I’m sure just a pocket bike motor

[@fjb4750]

@@DktheWelder awesome. Thank you!!!

[@chriss8206]

OK instead of the clutch on your motors even if you do clutch them there's something called a pop off valve that pop off valve allows you to shut the gate that goes over the end of the nozzle and then there's a mechanism maybe a servo in your case it allows you to go full throttle and then rapidly open that pop off valve For instant high RPM thrust they use it on drag boat applications if you're interested in that for any reason

[@DktheWelder]

I have seen those! Thanks I think I’m making enough power for it to be useful though

[@atifjeffreys2748]

Do you sell the coupler to connect the 2 engines or know where to buy it

[@DktheWelder]

Na but I sell a drawing for 3d printing it for like $2 search dkthewelder on CG trader and you should be able to find it

[@tonygoodman6523]

Does u have a file for the coupler

[@jimciancio9005]

With the engines timed @ 180 degrees apart like you're trying to do you only thus need a single expansion chamber and a 2 into 1 header pipe, that is just something which may help you with space for your project? They actually run up to a 3 cylinder engine on a single exhaust expansion pipe, being one cylinder is using it at a time, it's not as perfectly efficient as a individual expansion pipe, but it's definitely usable for a 2 cylinder engine. Hope it works out for ya, good luck mate.

[@DktheWelder]

Yeah I see snow mobile motors are like that I didn’t want to try it though in case I messed it up somehow. Thanks for that maybe something I could try in the future

[@sscustoms100]

Watched all your videos absolutely great stuff I actually made a video and mentioned U I had a idea that you could possibly use if you didn't want to use the 3d printed park that connects to the flywheel

[@DktheWelder]

Cool thanks I will check out your videos some time👍