Crosskart Build #6: Suspension

[@matthewmoilanen787]

You did good on the explanation of the "motion ratio". For rough surface use ie motocross quad riding, static sag is typically adjusted to 1/4 to 1/3 of available travel. This is with driver weight added. Motion ratio should "always" be calculated using the tire contact patch as that is where the load input is applied. Oh and shock angle spring rate change is quick and dirty calculated at 10% loss for every 10 degrees. As u are an engineer I'm sure your trig calculations are more accurate. The fact that travel length is shortened when mounting the shock at an angle may also be something that may be considered. Coming together quite nicely!

[@timothywilliams2021]

Glad to finally see someone cover the spring angle issue. I've had to deal with the same thing building hotrods. Seems a lot of people don't know this. I've had to explain this too many times.

[@thewhiteeazye2728]

I didn't know any of the math but I figured out of my first go kart that the more angled my shocks where the softer they got. I just chalked it up to leverage and didn't put much thought into it. Trying to build my own single seat buggy/ cross kart hybrid and have no idea what the hell shocks to get because I didn't know any of this 😂

[@danielnunez3518]

@@thewhiteeazye2728I got long travel shocks set up for a yfz 450. Roughly the weight

[@StoryOfJames.]

22:10 I wish I knew more about the crosskart history tbh. The first kart style buggy I seen was the Honda Odyssey. I remember dreaming of that thing as a child.

[@KJRaycing]

The history is actually pretty cool. It was one man with an incredible idea, definitely look it up if you get the chance.

[@Tampaboys]

Heck ya bud this build is coming right along super awesome can’t wait to see this thing ripping thru some laps I have a old quad I want to do something with

[@KJRaycing]

Thank you. Old quads was the whole idea 😁. Just wish rear ends weren’t so dog on expensive. I may try a straight axle version, after the two seater...

[@johnnynewell4379]

Looks great. Can’t wait to start mine. I’m tracking some stuff down right now. Having a problem finding a IRS. Only seen a few Polaris outlaws in my neck of the woods and there on the expensive side.

[@KJRaycing]

You gotta wait for the right one to pop up. The good ones that are priced low go very quickly. I waited 10 years for one to be in the price range. If i had known how awesome it would be i probably would have spent a little more to get this started.

[@larrycorkum2397]

just purchased the vf 2 plans gonna purchase vf 1 next as first for me and wife lol cant wait to send pics of build progress

[@KJRaycing]

Thank you so much! I can’t wait to see your work, these are all coming out so great.

[@chrismahoney7213]

Great job!!!!

[@ironhead9507]

I'm going to use this video to emphasize the importance of math,geometry, ect to my son because I'm going need help lol

[@bigmikeyc83]

Im confused u already showed how to put arv front a-arms now ur changing them ? What atv are these new ones off ?

[@KJRaycing]

They are the same geometry, I got a donor bike that had nicer front a-arms that were fully adjustable. It’s really not that confusing; use atv front a-arms of your choice. That is what this video shows 👍

[@KJRaycing]

They are aftermarket raptor 660 a-arms btw.

[@howardsgarage9659]

I'd probably do the engine first and then do the pedals after so you don't have to redo the pedals to do the steering rack and pinion

[@KJRaycing]

The rack is already done 💪👍

[@g00gleisgayerthanaids56]

Anybody confused on suspension geometry should check doug bug out on youtube, he has a fantastic video with a wonderful mock up demonstrating proper geometry.

[@KJRaycing]

Doug Bug is absolutely awesome. This video is how to best adapt atv suspension to a crosskart though, not how to design and fab your own. As you see by the action videos of my karts, the geometry turned out to be pretty awesome 👍

[@g00gleisgayerthanaids56]

@@KJRaycing oh yeah, for sure! Yours came out great and if i followed this exactly, then im sure id be peachy keen as well! I referenced doug mainly for the cardboard mock up, it seemed like such a handy tool for figuring out the proper shock mounting position for that 90° at full compression. I didnt mean to imply that anything was wrong or improper with your set up. Just wanted to add to the reference for those of us who may be making our own or sourcing other a arms where stock mounting positions definitely wont work.

[@vicman440]

are those rear shocks also from a polaris outlaw?

[@golfish8589]

I have seen a few of your videos since I decided to build the smoothest riding golf cart possible. With in reason. I am leaning to building from scratch. Plus maybe using atv parts. I would also like it to be 4wd and possibly front and rear steer because I plan to add about 3ft between the wheels. I have worked on cars most of my 60 years. But never fabricated anything like this. It seems that most things should be figured out before getting started. Do you have time to help and do the math for me?

[@KJRaycing]

That’s awesome you want to build, definitely grab some plans and see what you can do 👍

[@everythingcustom4034]

The fact the I literally pullled a calculator out and understand everything gives me lots of Hope🤣

[@everythingcustom4034]

Since im the first one to comment, I VOTE ENGINE 🤣

[@emilythegermanshepherd7425]

Okay I'll bite LOL I'll be the only one to say pedals next LMFAO

[@ians1464]

That looks great. Looks lite to. If it had taller tires do you think a sway bar would be necessary

[@KJRaycing]

Yes

[@INDRAMotorsport]

I am for engine next ;)

[@claytonheck3253]

Makes sense to me to to engine next

[@bghorn01]

Could you post a video or some pictures and info on Facebook about how to change the setup to lower the ride height for autocross or other asphalt stuff?

[@KJRaycing]

I can do that. How much are you wanting to change the ride height? The easiest way would be to swap shocks and tires and wheels since both require different setups mostly in that department. But the other way if you want to use the same shocks is to add a second mount and tabs to reposition the shocks. Because of shock clearances, they would need a separation of 4-5 inches minimum. Does this answer your question?

[@bghorn01]

Yeah good question on how much to reduce. I would think about 5" suspension travel would be a good compromise between performance and lower center of gravity. What is the travel of the kart the way you built it in this video? Thanks.

[@KJRaycing]

I haven’t measured the travel but with 5” of clearance and it bottoming out right before the skid hits and 2” of sag, i’d say 6-7 inches ballpark.

[@Darkeiser.7]

Pedals man. I'm actually more curious about them than the engine right now.

[@KJRaycing]

You’re not going to be very curious when you see how much they cost... a good chunk of the budget goes to the pedals for safety. A 100mph machine has to be safe from brakes to throttle to clutch. But when you see how easy a racing pedal set is to install and adjust it may help justify the cost. Thank you for the comment.

[@jgang53]

How to change the boots on ACV joint

[@Niklassjulander]

Nice work, but isnt the preload at almost max? What I can se, you cannot tension the suspension more whith additional weight?

[@KJRaycing]

Thank you. The preload is actually at min settings, i have 2” of thread before i have to look at other options. I guess i should have said that in the video, “start with the worst case scenario.”

[@Niklassjulander]

@@KJRaycing But the tension " nut" is almost at the bottom, shouldnt it be att the top for minimum preload?

[@KJRaycing]

The tension nut is 2 inches from the bottom. I took the weak dual rate spring off the top because it is worthless unless you have more ground clearance for progression.

[@Niklassjulander]

@@KJRaycing Ok! Now I understand, keep up the good work 👍

[@KJRaycing]

Sweet! Thank you!

[@BrianW2979]

What is the radius of the die on your bender? Just looking at that lower bend in the front hoop and wondering how tight or loose it would be.

[@KJRaycing]

I use 3.5 clr for the 1.5 and the 1.25 according to 3d tubing regulations. I would like to do the front in a 4.5 or 5.5 but i didnt want to have to buy another die.

[@BrianW2979]

@@KJRaycing I am buying a bender that comes with a 1.5 inch with a 5.5” clr, will I be able to use your plans or do I need to have the same dies as you to get the bends sharp enough. Not sure if the bends would be too gradual.

[@melvinwood8957]

Are you setting your ride height with shock fully extended!?

[@KJRaycing]

I am and adding about an inch and a half for sag. I tack the mounts for a final setting if needed.

[@everythingcustom4034]

Adjustability they need! 😆

[@andreimail]

why you dont use a raptor700 engine? it has reverse

[@KJRaycing]

Oh i would love to brother! This has a budget of only 5-6 thousand dollars. Hard to find a raptor 700 for that price alone not counting conversion parts.

[@bobbyparham4253]

What shocks are you using on this front suspension?

[@KJRaycing]

Polaris outlaw 500/525, but most atv shocks will work. Look for the threaded preload adjustment if you want to have a really nice setup.

[@kennethshuler8253]

Be interested in doing a custom build for a client ?

[@KJRaycing]

Would you be interested in paying way more than you think it’s worth? If you want to buy one check out sierra cars 👍. But thank you, it’s always flattering when someone wants me to build for them.

[@LuisDiaz-kg1fy]

What these new a arms came out from?

[@KJRaycing]

They are aftermarket yamaha 660 raptor a-arms.

[@justinalexander9244]

what exact polaris outlaw are those front hubs off of?

[@KJRaycing]

Any. The 525 or 500. They are the same. Chassis is set up to use nearly any atv front a-arm setup. I actually ended up using Raptor 660 arms.

[@RELAXnRENOVATE]

@@KJRaycingare those the extended raptor A-rms or normal OEM?

[@Arcangelo27]

Mi mandi i disegni ?!?

[@yasminemotor1989]

Tolong dong minta ukuran nya .. panjang.lebar.sama tingginya berapa...

[@Darkeiser.7]

Sierra kart. 40k ...Nah. Build my own 100%!!!

[@Strawberry_RL]

What rule set are you building this kart to?

[@KJRaycing]

Goole crosskart rule book. It is the crosskart extreme pdf. Only 14 pages. I’m sure different leagues adapt their own rules but this has been the source of everything for a long time.

[@Strawberry_RL]

@@KJRaycing thanks!

[@spencercoates9067]

What did the A arms come off of?

[@KJRaycing]

They came off a yamaha 660, not stock though. The front of the frame is set up to accept a lot of different parts.

[@luisayala9897]

Nice, that is how my build would look like.I have an original par of those a arms. Got them from ebay for 200 Shipped. With everything except shocks. I Will be using a 500r from a Kawasaki ninja. Loving the look already👍

[@KJRaycing]

That is going to be a fun machine! Thank you!

[@cadillaccrow808]

do the engine next ok