Mini Crotch Rocket Build Part 3

[@memorris2]

After watching you for years, i think the fabrication you do making parts has become incredible!

[@Nunya_Bidnez]

Your so right. I'm impressed and this is not an easy task.

[@neckcrank2663]

I think that red shock will work! Just reposition the top angle more. Also the ride height needs to be with you on it. So it should sit sit a few inches even higher than it is unweighted.

[@gregholloway2656]

Agreed. And he could kick the bottom aluminum mount forward an inch as well.

[@deadslow201]

It is also easy to calculate needed spring rates. For example: Lets say rear suspension travel is 100 mm, and rear shock travel is 50 mm, then linkage ratio is 100/50=2. Bike mass 100 kg (use scale) and half of it (use scale) is on rear axle = 50 kg. Rider mass is 75 kg (use scale), and 50 kg (use scale) of it is on rear axle. Total mass on rear axle is 100 kg. Without preload, if we want rear suspension to compress (loaded/rider sag) 50 mm with 100 kg load, then spring rate must be 100 kg/50 mm = 2 kg/mm on rear axle. If linkage ratio is 2, then spring rate in rear shock must be (because of spring rate physics) 2^2 * 2 kg/mm = 4 * 2 kg/mm = 8 kg/mm. And if we want to rider sag to be 30 mm (50 mm - 20 mm = 30 mm), then we must add 10 mm preload to shock spring, because linkage ratio is 2, which makes sag 2 * 10 mm = 20 mm smaller. And then go to amazon/ebay etc...

[@mdnovaman]

Red shock looks like it will be perfect.

[@joeyarola2620]

i agree when his feet are off the ground on that bike it will be perfect!

[@ianbuilds7712]

@@deadslow201you're right it is a lot easier than you make it sound and after all these years he really should be able to calculate spring rates and gear ratios before it's built.. lol I put a scale under the rear wheel and sit on the bike (preferably with the suspension somehow held rigid) and multiply that weight by the leverage ratio the wheel has over the shock (ie if the swing arm is 4 units long and the shock is only one unit away from the pivot the wheel has a 4 to 1 mechanical advantage) which gives you the static force the shock will see at rest... Your spring should be stiffer than that static # by quite a bit.. pre load and the angle of the shock have huge effects on the ultimate stiffness but if the static # on this build were 400🍎 I'd probably start with a 700🍎 spring...

[@colbyolsen3120]

That mini bike is looking sick

[@murraymccann1417]

Lots of guys use CAD, (cardboard assisted design). As far as I can tell, you’re the only one that uses BAD, (brick assisted design). It’s pretty cool that the bricks come out on every project.

[@FarmerFpv]

Pretty trick huh? His medulla oblongata is operating perfectly.

[@morganhill9642]

Flintstone engineering blocks

[@Hellsong89]

I would only add peace of plywood with some felt on it as top layer, so say front shocks do not get scratched and its good habit for when vehicle is ready and some changes needs to be done to have felt surface be first thing contacting the frame.

[@levisylvester]

Painted frame looks good!

[@bryanmorgan8501]

When you sat on it and it went to the floor, the song that popped into my head was "all my friends drive a low rider" 😂

[@Lucas12v]

This thing is turning out really cool. I wouldn't dismiss the red shock so quickly though. It didn't look too bad to me. Maybe with some adjustment, it could work.

[@vkrazy4568]

I agree

[@gavinabdul7762]

I agree

[@DatBoiOrly]

you could make some fiber glass panels for the plastic bits

[@acurarl9929]

That red shock is mint lay it down a touch and move mount up and done. Did you sit on it. For 3.5 inch travel with 1 inch compress at ride hight your hand bounce test looked spot on but you gotta sit on it. Also with the swing arm at that aggressive of angle it’s going to seems stiffer then if it was laying more flats and lay spring lil more flat as well.

[@2jzfox...]

Its winter time to build a little snow machine with a big motor. Elan great candidate.

[@alaska4229]

I really like the adjustability of the rear shock with that slider bracket that’s pretty cool

[@dormantmenace]

The upper and lower tripple clamp are not typically welded to eachother. They move independently allowing for wheel alignment. They simply clamp in place at fork tube. In fact I've never seen them as one piece on any motorcycle I've ever encountered. As far as the rear shock. Just find a front shock of a newer name brand quad. It will be a real shock and you should be able to order different spring rates for it. Or a kx65 or ktm 65 rear shock

[@Nunya_Bidnez]

Every build you prove to us the youth's hands and skills are more alive than ever. Keep it up. Faith in the youngsters needs restoration now more than ever and this is proof its not broken.

[@cinnamonrollypoly]

Don't think we don't notice the painted parts in the background. Lol, looking forward to next week's video!

[@ranaldodavid201]

Yeah likewise lol I can't wait to see it.

[@takerkanefan108]

You should check out his instagram, he posts pictures of behind the scenes stuff including the painted parts in the background

[@pondafarr]

For the shock position: as the shock lays down more, the ride becomes softer (but needs a higher spring rate), and as the shock is more vertical, the ride becomes firmer (and you can use a softer spring rate). Of course, it looks like you need a significantly firmer spring than you have lol

[@deadslow201]

It is also easy to calculate needed spring rates. For example: Lets say rear suspension travel is 100 mm, and rear shock travel is 50 mm, then linkage ratio is 100/50=2. Bike mass 100 kg (use scale) and half of it (use scale) is on rear axle = 50 kg. Rider mass is 75 kg (use scale), and 50 kg (use scale) of it is on rear axle. Total mass on rear axle is 100 kg. Without preload, if we want rear suspension to compress (loaded/rider sag) 50 mm with 100 kg load, then spring rate must be 100 kg/50 mm = 2 kg/mm on rear axle. If linkage ratio is 2, then spring rate in rear shock must be (because of spring rate physics) 2^2 * 2 kg/mm = 4 * 2 kg/mm = 8 kg/mm. And if we want to rider sag to be 30 mm (50 mm - 20 mm = 30 mm), then we must add 10 mm preload to shock spring, because linkage ratio is 2, which makes sag 2 * 10 mm = 20 mm smaller. And then go to amazon/ebay etc...

[@raulpavert4420]

@@deadslow201 great explanation

[@kasuraga]

you also gain suspension travel as you lay it over

[@BobbyOfEarth]

That shock angle is referred to as, the 'cantilever' angle, where changing its angle defines the ratio between shock compression and wheel travel vs. a given spring rate.

[@malooooooooo8]

Nice work with this pocket rocket, it’s gunna look mint. Try a down hill mountain bike shock on the back end, should be able to find high quality shocks that will take the weight.

[@bryduhbikeguy]

Good idea.I looked at many different springs to put on my shock as it was a bit squishy.So many rates to choose from.

[@dirtyhooliganmx4337]

I see a green machine being painted in the back that color is perfect for the rock bouncer mini bike is looking good keep it up

[@JoseManuel-lj4dk]

And this why I don't miss a single episode from your channel Chris,🤔 I always learn something new on how to be creative with metal , great video and project 👍👍👍

[@Halfgaar1]

you are a true genius when it comes to frame building! I enjoy your work!

[@memorris2]

Just gotta find some rad fairings to fit to that thing, and itll be one of your coolest builds imo

[@drewtooker4243]

Some custom sheet metal fairings would be badass

[@lifeononeweel3008]

Whats fairings

[@cinnamonrollypoly]

Could just cut up some plastic garbage cans and heat them to shape. Jake the Garden Snake does that, and it worked for him. Not to mention that garbage can plastic is cheap and tough.

[@memorris2]

@@lifeononeweel3008 side fairings are the plastic sides that go around the motor and the front fairing is the plastic front end that has the windscreen and light(s)

[@memorris2]

@@cinnamonrollypoly that is a super legit idea!!!!!

[@BaileysDad369]

Use 1 Air ride shock from a Harley Softail. The length should be close and it would have infinite adjustability. Keep the great videos coming!!!

[@stephenmooney3198]

Use aluminum sheets to make your plastic body covers! Bend them into shape!

[@huntereaton8909]

I saw the thumbnail and thought why . I watched the video and said he'll yeah. Great work can't wait to see it run

[@UncannySense]

That chonky shock didn't seem so bad, I'd speculate with it installed on the least resistant angle and a bit of break in riding it would soften up.

[@toddabbott781]

I would have made the side bars up front that connect to the forks bend down instead of up so they would protect the engine more and become a better mounting point for the cooler. You are also going to want some padding on the seat, so I would lower the tail down a few inches. When sitting on it you would also. The idea of the suspension is more about drop than going up and to start at the ride height while under compression. The angling of the shock is to change the mechanical advantage of the shock, not the ride height. Use he red one and tip it forward more. If the angle is enough you might have a 3:1 ratio on the shock travel, so the 900 pound spring will work better. Move the height though so it will also be sitting at the desired ride height while you are on the bike.

[@robquattro5419]

Loving where this thing is going. I feel it deserves slightly bigger wheels though. Maybe some moped/scooter wheels would be better suited to it? Possibly make it handle slightly better too? Only a thought :)

[@caccadu12]

I totally agree with you. With the bike taking shape the wheels just have become way to small

[@robquattro5419]

Also will give more ground clearance allowing for suspension movement?

[@garrettstevens2232]

If he got DOT legal tires and added some basic lighting he could make this street legal.

[@barthanes1]

Scooter wheels would be perfect.

[@csorrows]

@@garrettstevens2232 Most states require the frame to be welded by a certified welder. Also, he would need the title to the engine. I'm guessing as it was scrap, he does not have this.

[@myturkishlife1777]

I would probably go with the red shock too.. maybe a simple 2:1 leverage mechanism as found on motorcycles ... Great fabrication work, gets better every episode 👍

[@limitlessbuilds]

You can get a cheap mountain bike shock with 800lb spring. Would probably fit the bill nicely! Also, please add a roller or slide so the chain doesn’t ruin the swing arm.

[@exCR-it3ex]

That red and black shock looked perfect

[@richardtillichE36]

you can also put the aluminum swingarm in some dry ice and weld the last spot, the cold from the ice will help stop the gasses from expanding. it works great!! :)

[@RJHaaland]

Enjoy watching the build. Perhaps you can coin the term "eye ballin' it choppers" and make it a reoccurring build theme every once in a while to mix up all the builds you do. Thank you for the entertainment and the loads of work you put into makin this happen.

[@ratherbfab-n848]

as always chris has outdone himself again...lol this thing is gonna be awesome when its finished.. well done love watching the channel keep em coming!!

[@g0ldensample21]

The music choice was pretty cool. I was mesmerised, and en-tranced

[@gargar209]

After the tank,gas, seat, you and all else the red spring seems perfect.

[@desertratstoys]

I love watching your builds! That frame looks awesome, and your engine release is flipping brilliant! I love watching your problem solving processes.

[@caccadu12]

This thing looks epic! I kinda was hoping for more of a somewhat ridiculous chopper build with that V-twin but as I said, it looks pretty sweet

[@morganweast4228]

It's a baby duck.

[@paulbailey4152]

Im loving this build man keep up the great work can't wait to see the first test ride

[@tillmanxl6914]

Chris it looks good, I have a suggestion for you at 11:00 in the video. If the "center section" of the frame was Drilled and Taped round bar, front and back you could use 4 Bolts instead of all thread. It's looking good 👍

[@malooooooooo8]

I second this idea. Good thinking TillmanXL.

[@ratherBweldingChris]

Dang that’s a good idea. I may have to do that in the next video, thanks 😊

[@matthewf1979]

That red shock is probably pretty close to what you’ll need by the time it’s completed. You being directly over it has a pretty big impact on its operation.

[@vtscratchalot4423]

Love the videos...While watching I get so into it I picture myself there working with you love that kind of thinking GREAT STUFF can't wait to see it finished...

[@cadecarp11]

This is a build I've been dreaming of since I was a little kid and you are executing it to perfection

[@MIKEH.777]

Your pocket rocket is looking fantastic. Maybe heat that red spring up so that it looses some of its tension and it won't be so stiff. I love it and can't wait to see it done. Keep up the great work and God Bless you and your family .

[@mauricemagiqceo]

Use plastic tubs cut the shapes and angel the shapes of the body parts with a heat gun

[@captainlandyacht1328]

The red one looked perfect for a mono shock to me. I'd try it

[@AviationAviation]

Your Mini bike you are building Looks like a beast I can not wait to see the end result Keep up the good work you do amazing

[@CarlosHenrique-cd5ew]

This mini bike is getting mad!! 🤌♥️

[@BUILDNIGHT]

Best looking project yet, Chris…. Looks just like a Pocket Bike with a Monster Motor! LOL!

[@Timmy6216]

That thing is going to be absolutely wicked and I am so totally looking forward to it

[@iainlangley]

I spy with my little eye, some freshly painted green frame parts! 🤔 Can't wait to see the buggy painted and finished. The crotch rocket is also looking bad ass!

[@scotttod6954]

Crazy carpets make for great panels. Easily moldable light weight ,cheap and they come in great colors.

[@metalman065]

I enjoy watching this channel, But it's hard to believe that you have No sponsors at all, unless you choose not to have any. You Fab basically Everything you do, Which I think is Leaps and Bounds Above Other KZbin. Plus You Do Everything On Your Own without Any Help, I've watched you struggle over the years do everything by yourself. You've Earned my Respect Because of The Way You Do Everything !!!!👍👍👍👍💯💯💯💯

[@ratherBweldingChris]

Thanks man. I don’t want to sell out just yet😆

[@jammils38]

Man that looks so good. I lmfao when you sat on that thing 🤣 that was hilarious! I would almost bet your underestimating the red shock tho. I feel like it should work out well in one of the positions. But Idk? However duel rear shocks might look pretty sick too.

[@Yokaylob]

I wouldn't go to cheap on shocks.. maybe a shock from a snowmobile or something of that nature.. keep up the awesome fabrication my man.. you're probably one of the best on KZbin atm..

[@mando719ad]

You know what would be sick...if you built a hub less version of this build, but with large size wheels too.

[@coolbros2010]

Maybe try a shock from a Honda grom they have huge aftermarket support and selection and are also small in size

[@buffmotorsports4460]

The best tool he’s ever purchased for this channel are those calibrated bricks he uses for everything.

[@JNET_Reloaded]

get adjustable shocks sometimes you can just change the spring.

[@bstarnes514]

Had the same issue when I built my pocket bike.... I ended up doing dual rear shocks...We damn near have the same setup with the adjustability too. Good stuff as usual brother!

[@RandysRides]

Ridiculously awesome. lol. Can't wait to see the painted parts assembled !!

[@markbenton4370]

Use the red shock you already have . Also change the rear swing arm attachment point to the bottom of your frame, and the bike wont bottom out so easily ... You are using a bigger engine and you an adult who weighs way more than a child .. So You will need a bigger shock with stiffer spring rate .. Great build so far..

[@xyic0re714]

I really think that red shock will be perfect

[@Kenneth-fz1ek]

I feel like maybe u should put bigger tires on it but it’s coming out good tho

[@felixw1365]

I think that removable lower 'engine-mount' does help with the rigidity of the frame, if it's true then good for you

[@Dead-Walking]

That thing is looking pretty slick!

[@FarmerFpv]

This is looking more and more like a Ducatti Monster or the Multistrada V4 every time you work on it. Looks fantastic, Chris. Build me one, I have death wish, lol.

[@diablowigglz]

Seeing those painted parts hanging from the CBR is awesome, I can't wait to see that monster assembled. Also this bike is gonna be great once it's finished. Thanks for another week of great content and keep up the good work!!!

[@haydensmith9064]

with the weight of that motor and you on top i think that red shock will be perfect on the softest hole setting when its done as it will end up much heavier and also look so much better with the shock on that most tilted angle! also ther is still adjustment in that shock and it willnot bottom out over bumps.. coolest build so far 👌 i have been saying for years on channels to do a v twin mini bike so i love it. please do some v&h style twin exhaust for max awesomeness 👍👍👍

[@stevelecain886]

the mad fabricator at it again, great job.

[@wippitywine2]

Your my role model. Your videos is what made me like building

[@rayrayadkins6178]

I love the way you are building stuff

[@njmxjunkie3128]

Honestly that red shocks pretty close to perfect, maybe what you can do is take a torch to one or two of the center coils to take some of the temper out of the steel in the spring and make it lighter

[@keepitrealgangk.i.r.g5559]

I love everything you come up with just so amazing to see what you come up wirh...

[@murmur3966]

Hey big guy the crotch rocket is looking incredible. I think you should go on using the heavy duty shock you have for several reasons. 1. You are still adding weight to the frame tank and seat etc. so having the stiffer spring then you know it will take the extra without collapsing. 2. You need to respect the little beast you will be putting between your legs. I (HOPE) you wear a real leather jacket, pants or chaps, boots and a helmet, which will add another 40-50 lbs or more pounds to your weight. 3. Crotch rockets I've ridden always have stiffer suspension for better cornering and control. 4. With a stiffer rear setup, you should be able to keep the chain from snapping and making you crash. If I was you, I would turn the swing arm pivot into a Jackshaft point then there would be direct drive from the motor and perfect pivot range for the swingarm. That way you will never loose a chain or god forbid have the thing snap and spin around and take off a leg. Keep up the awesome content my friend. Stay happy and healthy.

[@scottcrabtree8923]

Add air bag rear suspension. It can act as kick stand when u let air out. The frame will sit on ground. Alot of custom bike have that. Looks amazing!!

[@drewgraff7748]

Frame looks awesome!

[@mikeyacullo]

Bro this thing is coming out so dope. I love it

[@Xempt_One]

Holy shit, just popped into my recommended. Im just finishing off my hyosung gt250 powered go kart. Ive got a few safety things left to do before its driveable. This is a cool project man

[@bwag4007]

Look up "static sag" for racebikes. I'm going from memory I believe its around 25%. So with the bike fully built, fueled, oil filled, battery installed, and fully geared up rider, measure the travel distance at a consistent point(axle straight vertical usually, or some consistent ref points), unload the shock basically hang the bike so the tire just touches the ground, then take the matching distance when bike is complete and rider on it in full gear sitting on it(bounce a few times to let it settle in). For example if you have 4" total travel, the static sag measurement should eat up 1", leaving 3" travel remaining. Great stuff, can't wait to see it do some ripping around!!

[@olingerscreations]

True super pocket bike, I love it. I dreamed about one of these since I was a kid and had a super pocket bike and was disappointed with it.

[@calholli]

I think that red spring would work great... You're pushing on it without your weight on the back. It looks pretty perfect to me. You want it to be fairly stiff if you plan on going fast.

[@MrRodriguesagas]

nice job dude. the mini beast is coming!!!

[@darthgbc363]

21:45 Maybe install cams on rear axle for tensioning. To keep axle aligned. Similar to Harley.

[@trevorcrane5271]

Imagine getting that frame anodized would be pretty cool. Love the build😁🔥

[@csorrows]

Um, the frame is steel man. Can't really anodize that unless you like colored rust coated metal. Now powercoating would be a great option and typically is much more durable than standard spray paint if prepped and applied correctly.

[@garageguy5174]

Burn outs will be so easy!! The stiff one is fine, just move it back a little? Great vids!!

[@blueballs5150]

I might change the wheel size. Those tiny tires are really going to change the gearing.

[@gmfb33024]

The rear suspension is so nice

[@joshvandruff1790]

I can’t wait to see this thing rip! Awesome work.

[@rileyrodriguez1452]

Looks good

[@FangOfTruth]

You did what I thought with the tail section. You lined it up with the side bars going just above crankcase.

[@-jan]

high rise handlebars will look cool in this thing

[@th3d3wd3r]

Looking awesome. Could double up the smaller shock. Two rear shocks side by side look pretty cool.

[@th3d3wd3r]

Yeah, do that!

[@Kc-ep7gh]

I think the red one will be perfect for it.

[@randallweaver7034]

Keep up the great vids! I vote to keep the red shock.

[@upcyclegarage7685]

Suzuki RM 125 or 250 shock has the pre load and travel required. new ones have more adjustments.settings

[@thatboiileroy_17fl75]

Loving the build keep it up 🙃💪

[@orshaked8013]

Looking great! that build is awesome, one thing i think need to be change is the pivot point for the wing arm it seems it a bit too high and the chain will grind the swing arm, u want the swing arm and the chain not touching each other on the tension part of the chain , gl! good project

[@batorback6303]

so beautiful ! it looks like it want to eat the road !

[@gabriellight5012]

this madman will end up killing himself with these crazy creations of his!!!!😂😂 Im from Brazil my Brother!!!

[@jessejohnson2089]

This is going to be awesome great work I can not wait for the exhaust I hope you spend alot of time on it!

[@skipsterz]

Gonna be a total ripper!!