Mini Crotch Rocket Build Part 2

Getting the engine running
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[@nickburns2034]

Episode 1 " I want to build something the size of this table" Episode 2 *Extends table* 🤣🤣👍🏽

[@Avetho]

I mean, that's one way to keep to the letter of the stated goal XD

[@1byte4]

WELDING NOTE: The heat is trying to expand the air through the final opening on the swing arm. Thats why you cant weld it. drill a small air escape hole somewhere obscure, then weld the top plate

[@34bartm]

Interesting. Thanks for your comment

[@landistitman2973]

learned this the hard way on DOM tubing. All my other welds were great until I got to the very last weld. It would always ooze out like playdoh.

[@spyder7758]

That's exactly what I was thinking

[@Lucas12v]

Ran into this problem many times. After everything cools off, you can usually weld the vent hole quickly if necessary.

[@sebsshed4517]

Great tip!

[@1one3_Racing]

One thing I've learnt about machine parts. Hang around auctions and old machine shops. 60 year old precision made parts for $100 from some bloke who's retiring are generally better than cheap brand new parts. The machines themselves? Generally sloppier than octomom. But the parts are usually top quality stuff you can't get anymore.

[@Adventure_Van_Upgrades]

when measuring the chuck run out you should always measure with a piece of known true round stock in the centre of the jaws not the external face of the chuck body , great addition to the shop once you get it dialled in, keep up the great work chris , im a keen follower from the uk

[@34bartm]

Yes exactly. Otherwise how do you know the round stock he is using is not bent. Certainly seems seems so the measurements are so different the chuck end and the tail end.

[@NVMDSTEvil]

Using tail to center with the round stock is a pretty good idea I believe, no?

[@jessewilkins6395]

im no machinist known true round sounds good from the throne im sitting on

[@itarry4]

Also he was supposed to face the plate himself anyway. It's just good practice to ensure its flat with the cutter of the lathe. That's why they come so much thicker than needed, so it can be faced on the lathe it's to used on. He should have made the chuck register better az well at the same time. It's part of how his channel is though, no research until he really has to and just grinding his way to understanding what works and what doesn't. It's his way to do everything including his builds which never go the way he intended but he ends up with something cool anyway.

[@Mad-Duk_Machine_Werkes]

your "Hole" in the swingarm is most likely due to being the last part of a sealed small area, the air inside heats up, and if theres dirt or oil inside that part of the tube it keep boiling out! if you had drilled even the tiniest little hole into the pivot tube it would have released the air and you can weld up that hole on top

[@whitepage8018]

exactly what i was thinking.

[@tgsubie]

Nailed it. It simply needs a vent hole.

[@th3d3wd3r]

I'd go as far as to say he probably wants to purge the air inside with shielding gas

[@ratherBweldingChris]

Ok that makes sense, I never even thought of that at the time. I will definitely try that out and see if it fixes the problem. Thanks

[@hoirulandilazis9464]

@@ratherBweldingChris piye lor?

[@AkPacerPilot]

I’m digging it… the bloopers at the end made me feel better, cuz that stuff happens to me constantly… thanks for sharing..

[@thomaspryor8202]

I have been critical of your machining in the past. But, not today. You killed it. Well Done!!

[@larrydavidson3402]

Chris, I really admire your fabricating skills and the things you do with the lathe. That rear swing arm assembly is fricken stellar!!!!!!!!

[@sonovoxx]

25:30 Is there a hole to let the hot air out? ...if it was the last weld on that part, you'll need to drill a hole somewhere else, it it will just keep blowing out! ...but I'm sure you know that already! Great build. It's getting really exciting - especially as the Monstro is one of my favourite Ducatis!

[@allenmichaud1605]

Same stuff this guy says

[@SHSPVR]

I agree

[@danielmott8830]

Was about to comment - needs a vent hole

[@MrArcticPOWER]

Yep, happened to me and it took me a while to realize.

[@albertpeterson7134]

RBW Amazing Build As Always. Thank's For Taking Me Along. Keep The Videos Comeing

[@mdnovaman]

Just a quick one on the 6 jaw. Multi jaw self cantering chucks are notoriously poor for accuracy. Even high end ones. Usually they have an adjustment on the side to help dial them in. But for any job you want to be truly centred if it doesn’t have the adjustment you always need to tap the Chuck true which is why the register on the backing plate is sloppy. Or you get soft mild steel jaws and bore them to suit the diameter of the part your machining. What you have done is great. But I’d just put the dial on the part and tap the Chuck true for each job if it needs it. It’s kind of irrelevant how true the body of the Chuck runs. It’s how central the part is that matters. Cracking work as always. And going for the Ducati monster style is a cracking idea. Amazing looking bike. I have no doubt that engine will be more reliable than the Ducati engine too!

[@beauson1983]

This is basically what I came down here to write, lol

[@sebsshed4517]

@@beauson1983 me to.

[@devenp.5508]

Other channels: “3:30 minutes of talking and sponsors at the beginning of every video” This channel: “And here’s the build you clicked the video to see”

[@FarmerFpv]

Since I'm Italian, I definitely cant wait to see how this turns out. Ducati Monsters are gorgeous bikes. You need to drill a pressure release hole on the swing arm cavity. Tap a nipple in it to prevent water from entering and getting stagnant.

[@mattsenibaldi707]

I totally can see this thing looking like one of those mini crotch rockets or like a mini gsxr that would be the coolest build project ever

[@ALWhiteAuthor]

That ugly spot on the swing arm is the final weld that's sealing up the air pocket. As it heats the air inside, it blows out through the molten puddle. Just drill a tiny little hole in the triangular piece of aluminum for the expanding gases to escape and it'll be fine.

[@lennym1273]

All you really need is good independent 4 jaw, yes it takes a bit longer to set up BUT your work will be spot on every time. While you where cutting the back plate you could have set up a small register to fit the chuck because 3, 1/4 inch bolts will not keep the chuck true when you go to do something with interrupted cuts...

[@bigjim8088]

I agree could have easily put a small register while he was there. I believe it would have come out better.

[@Crewsy]

I thought the same thing. He complains about the 1/4” of “slop” in the fit but doesn’t correct that when he machined the backplate. ¯\_(ツ)_/¯

[@danburch9989]

You want to tighten all three pinions. The scroll has some inherent tollerances you have to overcome by tightening all the pinions. Then check for runout on the mounted part.

[@joshvandruff1790]

This isn’t a mini bike. This is a mega bike! I love it! Can’t wait to see this come together.

[@FlyinBrian777]

Aluminum welder here. Next time make sure everything is clean inside and out. And on your final weld, turn the amps down a tad after it's cooled off. Heat is causing gas expansion and the gases are just finding the path of least resistance. Let it fully cool, turn the machine down and put your last dabs of rod on. It looks good.

[@halfnelson6115]

A trellis frame would look sweet. I say go for it, Chris.

[@WGPblackmagicSPECIAL]

That'd be awesome 👌

[@ronniewilliz153]

Just don't use a cvt tho lol

[@JoesRcAdventures]

Been ANXIOUS to see the rest of this build.. Gonna be a BEAST🤘

[@leonhatton7585]

I absolutely agree this is the definition of death on two wheels love it

[@jasonbirch1182]

It will be fast but it's really not very powerful. 28hp 16lbft of torque. A healthy predator is right there. Being able to dump the clutch will make it flip happy but not any faster than a little dirt bike.

[@alasdair4161]

I made a grinding jig to true my scroll chuck jaws, it's the ultimate way to get it perfect. Similar to running a boring bar through the jaws, just grinding with silicon carbide stones. It requires a precise ring to be clamped in the jaws (externally) to remove slop. Once done everything gets stamped for correct reassembly (repeatability) So far I've only had to do it once.

[@murk1352]

That's what I was going to tell you last episode. Do like a Kawasaki H2 frame where the engine hangs from the frame/ engine suspended from frame....👍🏻🏁

[@sempi8159]

Love the small builds! Great to see you are making sure you don’t get burnout!

[@TXH1138]

Cutting Edge Engineering , Kurtis is a lathe and welding master. His work is unbelievable.

[@34bartm]

Yes it certainly is. Love that guy's video. Cute dog too.

[@broo_shs]

abom79 its american master and CEE its australian

[@The2011tahoe]

That was so awesome to see you make the pieces and put them together … that was super helpful to see now I have more confidence in doing one myself ….. thanks for that

[@swiftfishin5680]

Do a giant road trip whenever it’s finished

[@acurarl9929]

Straight line rear axle to the drive sprocket. So your spot on man.

[@timleonard9762]

I’m glad your happy with the 6 jaw chuck! Also, I wasn’t kidding about putting in for a cnc plasma cutter!

[@cinnamonwombat6316]

does anyone else find it relaxing when the video starts and just goes into a long ass time lapse of him working? Just me? Okay.

[@Nunya_Bidnez]

Thats what im talkin about. Get it son. Like I said before. Your skill is better than the other guys in the machining area. Let it shine.

[@darrinwoodward14]

You want the swing arm pivot in line with the output shaft of the engine.that way the chain won't rub the swing arm through its travel.

[@MrArcticPOWER]

You know that it's not always gonna be in line as the wheel goes up and down, right?

[@darrinwoodward14]

@@MrArcticPOWER ? If both the engine and swing arm pivot are fixed mounted,how can that change with the arm going up and down? We are talking about the swing arm pivot point,right? Any motorcycle or atv I have ever worked on,the swing arm pivot is in line with the counter shaft sproket.

[@MrArcticPOWER]

@@darrinwoodward14 In line with what? If you only have 2 reference point, how can they not be in line?

[@darrinwoodward14]

@@MrArcticPOWER the swing arm pivot needs to b parallel with the output shaft of the engine.if both are "fixed points",there is no way it can change with the swing arm moving up or down.at least,that's what you said,that it won't always b "in line" as the swing arm moves up or down.the reason they are put into that position, is so you get maximum travel with the swing arm,before the chain starts to rub on it.

[@MrArcticPOWER]

@@darrinwoodward14 What you're saying doesn't make any sense. How can two points be in parallel with each other? If you got two fixed point, it doesn't matter where they are, if you draw a line between the two, that line will always be straight. The third point is the wheel and since it's not fixed, it's not always gonna be in line with the other two points. What you actually want, is that the 3 points are aligned at the bottom of the suspension travel. That way, the chain tightens up as the suspension moves down. It as nothing to do with the chain rubbing.

[@blueballs5150]

I’m always super impressed by his fabrication skills

[@brianrhubbard]

I'm a CNC machinist but I might can help. Use that ground bar stock to indicate it in. A truing bar would be ideal but the ground rod is basically the same thing. This way you dial in the part held with the 6 jaw. Same way you would dial in the tail stock but backwards. 6 jaws are awesome. Edit, Almost forgot. You could also chuck a large bearing race and indicate the I.D. The reason you would want to do it that way is to be concentric with the jaws and take out any error between the chuck body, the jaw scrolls and the jaws themselves. Hope this is helpful. Rock on.

[@josiahmitchell530]

I'm loving to see how this project is coming along. Also, I love the quality you put into your builds. Keep it up!

[@sebsshed4517]

You guys in the states are so lucky. So much available to your disposal for stuff like this compared to the uk. Love your videos mate. Keep it up!

[@MIKEH.777]

I love the mini motorcycle and I hope you can get back to it soon. You don't suck at welding. Keep up the great work and God Bless you and your family.

[@mercenarystagehand]

Add some mounting points for a wheelie bar while building the rear frame just in case. I am curious to see if that rear gear is going to be big enough. Would like to see some custom fairings. And keep up the good work!

[@oryxr5354]

Was looking for something to watch and you provided at a great time, thanks! This build is awesome so far, looks a lot like my first bike, was a R1 replica with a 35cc brushcutter motor, wasn't very fast haha

[@TheShowgunofHarlem]

Nothing better than Sunday night football and my weekly dose of Rather B welding

[@spyder7758]

Are you having hot gas causing pressure inside the aluminum? Drill a pressure relief hole somewhere else to allow you to finish

[@jessejohnson2089]

Definitely an awesome idea to do the miniature Ducati monster!

[@RedneckSwede]

Back in school we used to adjust the chuck by tightening it slightly and tapping it with a mallet at the "highest points". The needle barely moved at all after a couple of attempts. Not the best way but it worked for us.

[@steeltree-fabricatingandcu3796]

You can’t weld a closed off cavity The gasses inside expand and blow out the weld Try drilling a 1/8 hole in a spot you can’t see Sometimes you can quickly weld the hole after the rest of the welding is done After the part cools down

[@technerdy]

AvE is your man for these questions!

[@BobbyOfEarth]

Drill a 1/2" hole x 1/4" dp. thru that porosity spot (to interconnect the air cavities inside all those tubes) then clean hole w/brush. Drill a nice centered 1/8" hole on the bottom side of the cross tube (to vent gasses) ..then plug weld the 1/2" hole.

[@RLDeMerritt]

The chuck segment was only 7 thou from being ICONIC!!!!

[@phuketmusicscene9008]

I think your aluminum swing arm needs a vent hole to allow the expanding air to escape as it heats during welding

[@tristanmcnabb2741]

Allsome stuff buddy from cruzermans inventions . you and car's and camera's and Red beards garage and grind hard pluming are the only ones I watch .your work is so cool 😁🎉👍

[@Glens1965]

Out takes are too funny. Real life in this world.

[@mattmgm1994]

Another great idea to build would be a mini chopper bike! That is what I got with a simple 110cc. I be awesome to see what you would build! 😄👍🏻

[@xyic0re714]

Your channel has become my favorite, surpassing grindhard. good job

[@foxwolfworkshed5080]

This thing is going to be a deadly beast of destruction... Sounds fun! Btw, your creations have inspired me so much, please keep making these incredible machines. Have an awesome day!

[@TheOnlyJoshH]

Your drive is really inspiring

[@garthkerr621]

I’m so jealous of not only all the tools you have but your skill as well 😂 can’t wait to see the finish product 😁

[@schism47]

Ahh damn man. I would use something like a guage pin or a cut off old drill bit in your chuck to indicate the run out. That rod you had in there might be good but you would never be able to tell for sure. A guage pin in definitely true round

[@mikeyacullo]

This thing is awesome. Wish I had a shop like this man. Id be building shit just like this everyday ahaha

[@boone7777777777]

I like the idea of you using the engine as basically the frame. I like when bikes do that.

[@davidowen888]

Phenomenal fabrication skillset you have achieved 👏 ☮

[@barthanes1]

That's a new one on me. Never seen anyone expand their welding table on the fly. 👍

[@tobiasstaermose]

I cannot wait till the day you make a full alu frame! 👍👍👍 that swingarm looks so chunky, but weights nothing 😁

[@oldhillbillybuckkowalski]

If you snug your chuck incrementally from each location until its tight enough you will usually find that whatever piece of work you are turning will spin a bit more true. For stuff that must be dead on accurate I usually use feeler Guage straps as shims between the chuck jaws and the piece being turned.

[@matthewf1979]

The six jaw chuck likely needs to have the jaws ground on the lathe. Fairly common on the less expensive China equipment. Making a new back plate that registers to the chuck would be ideal for repeatability.

[@aserta]

Step 1, get a precision rod. Open the chuck, clean it up and re-do it without any kind of oil. Re-check your tolerances. If you find discrepancies, then you know (i do hope you checked every bolt on it). Once you're done, if you're still out, then machine a large ring, as close to perfect as you can (if you can find the race to a large bearing, that's even better). Put said ring on the jaws, and open the jaws against the ring, with medium holding power (or about as much as you'd use to not dent a surface). Now the chuck is open, and in that open position (the bigger the better) use a long shank motor and a grinding stone to regrind the jaws. Small bites, don't go aggressive, just kiss the teeth. Once you're satisfied, stop, clean EVERYTHING with the detail of a surgeon and take the chuck apart (always keep all the parts indexed in the same spot, index the chuck to the plate, index the jaws to their holes, and index the faces to the moving parts, never swap them in between) and re-assemble with minimal, non oily, lubrication. Guides pertaining to this can be found on both mrpete222 and Keith Rucker's youtube channels, both far more in depth. Specifically these two videos (will post the titles as is, no links cause Tuber): mrpete222's "MACHINE SHOP TIPS #147 Grinding the Jaws on a 3-Jaw Chuck tubalcain" and Keith Rucker's "Restoring a Rusty Bison Six Jaw Lathe Chuck". Both videos pertain to your plight. Personal observation, never expect to buy something from china and be hassle free. You're buying the raw materials, the assembly and fine tunning is up to you. This is not me admonishing you, this is just a fact of life.

[@keithw372]

try cutting a piece of material on the lathe and then mic it from end to end that is how you measure run out, not just a random piece you have.

[@assassinred426]

Well generally if the core is not at zero then nothing else will and the further out the worse it gets

[@brandonshudy789]

You generally would want the chuck to mate perfectly in a perfect world and also it’s common with high quality machines and components to machine a blank backplate on the machine to fit that chuck. But I prefer to matching clearance in my back plate so wen I have that job I need to indicate my material in I can loosen the chuck mounting bolts and tap the chuck around with a lead hammer to put my material on center. Your back plate has excessive clearance for not having much bolt pattern clearance. I would open up the holes on the backplate .02-.03 over bolt diameter to give your self some room to adjust things.

[@FangOfTruth]

Maybe the swing arm shock mount will cover the crater up. Or weld some medallions (mirrored to other side) that camouflage it.

[@ThiraEye]

hell yeah brother! lets go! another awesome video.

[@charlieritchel1492]

Hey man you're doing a great job. Keep up the good work. Oh and your welding has gotten a lot better. Way to go!!

[@wvflying1626]

Awesome job fine tuning that bad boy.

[@MrCornhole98]

Great bonus material, thanks.

[@johnwright2154]

Great fabrication, glad the 6 jaw chuck was good.

[@bossmanmoran4890]

First instrumental is hard and keep up the good work

[@Kikerumbo]

Having zero idea of welding... Was that weld the last one where you close all the holes where the air can get out? Can that bad spot of welding be because of the air inside getting hot and expanding, because it's enclosed inside? Maybe, making a hole so the air can't pressurize will solve the issue.

[@Lucas12v]

You have at least one good idea because you're 100% correct.

[@redneckreggie1867]

Super stoked about this build

[@dorightal4965]

Love the outtakes!

[@HostileHST]

26:00 maybe a vent hole is needed? Not a welder myself, but have seen some video's saying you need a vent hole to prevent that sort of blow out.

[@BiscuitTinOrchestra]

put the backing plate in the lathe... face it off and create a new "register" for the chuck

[@richball9576]

The problem you're having with the weld it outgassing on the final portion do to trapped air in the tube. You can drill a tiny vent hole and that should solve your issue.

[@alaska4229]

I love the Ducati monster aesthetic that would look awesome as a crotch rocket

[@mm_tuning_]

finally another video 🤗

[@PHUSII]

this project will be one of a kind awesome!

[@Kelvysb]

Cool build man, I love it, I used to have one of those Hyosung GV 250, it's not a a shitty Chinese engine, it's a shitty Korean engine, some years ago I quit trying make this engine work properly and abandon it to rust on my garage.

[@richardsteele6776]

I am looking forward to seeing more of this build. Will it be street legal?

[@AndreyNikolo]

I love you collection from trusted bricks for space positioning the components :) :) :)

[@totagamer5437]

I'm waiting for next episode Happy to watch😊

[@aserta]

I support the Ducati naked Monster idea. Naked bikes look so much better.

[@traindriva]

Music was relaxing to begin the video. No screaming guitars, drums ,cymbals or techno junk.

[@firepinto]

Back when I was a tool designer, the welder always told me I needed to design a vent hole in the tube so that it would not build pressure and blow the weld back. Maybe that is what happened.

[@michaelblacktree]

Just a random thought: IMO if the angle of the front fork matched the angle of the fins on the engine, that would be aesthetically pleasing. Not sure how that would affect handling. Anyway, loving the build! Keep up the good work. 👍

[@josephbedenbaugh7243]

If you have a 1/4 of play on the back plate, you can drill and tap 4 holes 90° apart on the OD of the chuck. It turns it into a adjustable 3 jaw or 6 jaw chuck. Research accu-rite and bison chucks. that's what we use at work.

[@avbangers1341]

You do really nice work! 👍🏻

[@colingrogan1401]

you should of used the head tube because it has the VIN on it so you could of registered and made it street legal.

[@bwxmoto]

Mini Monster. Very cool 🤘

[@addisme7561]

Machine the six jaws internally to match your lath like you did the backing plate, also take it apart and de-burr and get the grit and iron filings out of it.

[@detykketrner3331]

Ducati mobster is a 2 cylinder engine, and its only for 2021 they changed the design and went from tubing frame to the aluminium frame as on every other bike, I like the OLD monster look too :)

[@Davids70Chevy]

When you measure this like that make sure your indicator plunger is as close to perpendicular as possible to the surface you’re measuring. Not a huge deal but just a small thing I noticed

[@wags9777]

You need to face the back plate to Match your lathe. If you need to remove the register that came on the back plate its ok. put a new register on the back plate. You should always dial a Chuck in On a known concentric piece of stock and use the dial on the stock Not the chuck. Rinse and repeat for the 5C Chuck. After registering the back plate Leave your bolts kind of loose loose so you can knock the Chuck into concentricity Then tighten completely. Good luck

[@Rust_Belt_Fab]

I really hope you make this a mini motorcycle and street legal. 😎👍🏻