Mini Crotch Rocket Build Part 2 

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

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

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

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”

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

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!

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.

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!

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.

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

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

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.

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...

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

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.

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

You macnine a spigot on YOUR LATHE so it runs true to YOUR machine for the new chock to locate.

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.

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.

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.

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

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

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.

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....👍🏻🏁

You’ll probably end up leaving the Chuck key in the Chuck and spinning it up now you’ve taken the safety spring off.

As others have said you need a vent hole. Drill a small hole and tap it for a 1/8 threaded plug on the bottom. Problem solved

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.

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.

❓❓❓ When will we see build-offs between our favorite channels? We need an aspiring future producer and some capitol to fund a video series! ❓❓❓ (my money is on this guy!)

Check out Abom79 RU-vid channel for machinist questions.

Contact the ebay seller and ask for a partial refund. I've done this before and they returned 1/4 that I've asked for

Dude you are not tightening the chuck properly you should tighten all Jaws equally not just cranking on the one x

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

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

Abom79 its one youtuber who might help if you send him a message or mail,he is a master machinest.

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

A 400 dollar piece of junk but knowing you you will figure it out

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.

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.

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

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!

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

First and I love what you do my friend

I watched every video since the lifted video build, and ask myself,"why doesn't he build an Engine stand". 👍🏼👍🏼👁♥️🛴🏍

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

Chinese chucks be like: "custom machined back plate"

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

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

Muito show os seus vídeos, parabéns que o Pai Eterno te abençoe grandemente. Um abraço do 'Brasil' rsrsrs

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.

1st

Chaina Lathe Chuck...

Why would you clock it up off the outside of the chuck? Do it off the round stock in the jaws mate . Anyways great video 👍

finally another video 🤗

🙋🏼‍♂️boa noite 👍🏻🇧🇷

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

Thanks for all the work! I was wondering how come u don’t use the new welding rotating table when u weld round stocks? Is it possible to change the gearing on the rotating table to make it run slower? I was looking on that table for ever myself but after I watched a video and u explained that it’s too fast for ur welding skills it might b the same problem for me.

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

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

NOT chinese engine.... KOREAN!!!

You probably had some contamination on it, break out the acetone and clean the parts prior to welding.

Niece

Do a giant road trip whenever it’s finished

13:10 these is the same thing which i get.. i buy a hand drill when i used the drill chunk was like a duncing...

I'm noticing your transmission sprocket and your wheel sprocket are very close in size, which I suspect you may find is way to tall of a ratio and makes your acceleration rather unsatisfactory. Especially with such a small engine. Typically you want between 2.25:1 and 3.50:1, depending on available power, amount of loaded vehicle weight and desired acceleration vs desired top speed.

Is the rear cylinder’s exhaust going to clear that upper (horizontal) frame member? Looks close. Neat project, Chris.

It wasn't the chuck the pipe whas bent

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.

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. 👍

Esse projeto tá ficando monstro.

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

Adam Booth (Abom79) found when he fitted his first 6 jaw, that tightening each of the 3 points rather than just one, greatly reduced (or did not introduce) runout.

I’m always super impressed by his fabrication skills

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

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!

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 😁🎉👍

Lol, Hyosung is South Korean. Their engines are based on Suzuki engines. From the work I’ve done on them I’d say they bought the designs and made a few changes.

hell yeah brother! lets go! another awesome video.

Hey Chris ... Did you drill a vent hole in the swing arm ? If you didn't, the pressure and gasses will be escaping through where you are finishing up the weld and that could be the whole problem.

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

Chris… I’m a machinist. You’re supposed to turn the shoulder on your backing plate to register your chuck.

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

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.

Makes me watch to guy buy some tools lol that’s some very nice Machine work 👍🏾👍🏾

i think those engines are originally suzuki designs, chinese manufacturers buy the rights to build those, so the engines are not too bad overall. sure its not "the original" but also far from bad

.001 -.004 is about all youre gonna get from a scroll chuck.. so thats really good

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

Nice build. Keep up the good work. STOP ORDERING CHINESE JUNK

I am a machinist. How far are you from Charlotte NC? You should stop by.

the engine is kinda suprising me 14hp/cylinder its mean 125cc for 14 hp wow thats copycat of suzuki FXR150 is pretty powerfull

I have a Hyosung GT250 (2009) which might just have the same engine as you have here; If I'm not mistaken they actually use suzuki engines, customized by Hyosung. Might be important if you need parts for the motor ;) Also, the advertised 28 hp will feel more like 20 at 11000 rpm, but it has a nice grunt from 4500 to 8000

Good stuff. A thought…………when/if leaning, I see the front rotor hitting the ground.

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

Just an FYI Hyosung is a South Korean manufacturer NOT Communist Chinese cheap junk. Korean manufacturing quality is nowadays on par with Japanese products so it should give you nice quality & reliability, this according to one cousin who used to work for Sony, and another who used to work for Honda, both now retired.

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

This engine looks like a Hyosung engine. South-Korean with Suzuki tech. If It is It Cam rev UP to 15k rpm an its a Very tough engine with a bit expensive parts. By the way Nice video Man

The yfz-R3 motor weighs only 81 LBS, the bike has a top speed of 103 mph, and about 43hp and 22 foot pounds of torque. So on this little bike, the motor would be great, and it'd keep the weight of the bike down too.

Should've made it a chopper. Would've been epic. Try reading comments in your videos.

STOP!! 3 and 6-jaw chucks can be dialed in watch this video from Tublicane! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-E_Ks6GKKcs8.html Drill and tap 4 fine thread holes thru the OD of the chuck over top of the sloppy flange and you can adjust the chuck with those screws when needed.

Try to make a mini version of the hyosung GT250, its the same engine Or the GT650, just have changes in the frame (visualy noticible)