IRS Spool for Crosskart/Gokart for Mazda Miata Axles

Video shows how to build a cheap modular spool and rear end for cross kart. Was design for KJ Raycing kart. Total cost of spool, axles, and wheel bearings is around $300 depending on parts used.
Updated Spool Here • Budget IRS Crosskart S...
Buy the Spool here jdsgarage.bigcartel.com/produ...
KJ Raycing's channel
/ @kjraycing
Parts used :
Axles: www.carid.com/1993-mazda-miat...
Bearings: thebigbearingstore.com/1-1-4-...
Weld-on hubs: www.surpluscenter.com/Brands/...
Key stock: www.grainger.com/product/GRAI...
We have used this key stock on another cross kart with around 100HP and have had zero issues. This is also the same key stock that many snowmobiles also come with on the driven clutch.
Sprocket: www.ebay.com/itm/193657171335...
For all inquires email us jsaction4[at]gmail.com
#crosskart #gokart #buggy #snowmobile #Polaris #DIY #garage #HomeMade #BuiltNotBought

[@KJRaycing]

This is amazing! Thank you so much. I knew the collective mind of fabricators would lead to amazing and affordable fun!

[@jamesfraser9296]

This is an awesome video. Thanks so much for putting this out there! Would like to see your other videos on the rest of the rear axle.

[@aleehene]

Brilliant! I've been searching for an IRS setup like this for a long time. THANK YOU!

[@scottadams2800]

Thanks for the info! I just bought the plans and getting parts for this was proving to be difficult. Your ideas saved a lot of headaches, much appreciated!

[@stanleywilder6646]

Thank you for your video. In the near future I am planning on building a cross kart. For now I will love to fabricate a spool axle for an existing go cart that I already own.

[@bigmikeyc83]

Thanks for the video getting a spool figured out has been a big pain in the butt.

[@bghouse2853]

I dig this lot! Very simple. Would love the brakes and spindle videos too!

[@alphabob8156]

Another great video! Thanks for taking the time to put this together!

[@olsonspeed]

Genius fabrication, keeping custom parts at a minimum and utilizing off-the-shelf parts is definitely the way to go. Thanks!

[@NolanGerald]

You are doing the lords work. Such a simple solution. Thanks!

[@Landril]

Exactly what I was looking for. Very clear and concise explanation.

[@051biohaz]

Damn, that is super cool…I’m getting started on a buggy and your video will help out a ton…thanks for the upload..:)

[@jesse1136]

Thanks for sharing this. It's so simple it's brilliant and you're not just out here hawking CAD designs for hundreds of dollars. Very appreciated

[@jdsgarage701]

That's the plan of the channel.

[@markwood9751]

Good to see someone with the same problem as me! Left hand functions but with almost no dexterity, i can't even spin a nut on with my left hand either!

[@ericsimmons2947]

Simple and genius I will definitely use this application!

[@Blkbeard420]

awsome video brother, youtube needs more of this

[@profesonalantagonist]

Wow! That is super slick!

[@erichill5208]

Looks simple yet strong. The low cost is also a plus

[@dooby1445]

This is genuinely awesome

[@williamlanphar630]

Nice affordable approach to this assembly.

[@jdsgarage701]

Glad you liked it 👍

[@kevinschilling6813]

Awesome little spool

[@GOONRID3RFRANKLIN]

Solid work!!!

[@Jim-gi6ov]

Awesome design thankyou

[@edward1580]

This is the best video i have seen on a budget spool assembly. Would love a video on how the hubs were done. Awsome job.

[@jdstremi]

kzbin.info/www/bejne/hXK9oaBqi7GYps0

[@haroldsegur9524]

Nice to build on a low buck platform,I'm doing that soon,thanks.im subscribed,i want it all!

[@biglon62]

Thanks guys great fab work!

[@xod7861]

This smallest and best looking one so far

[@joey22877]

Thank you. I'll design mine a little different with my lathe. I'm planning on using a sled engine also. I'd like to see the drive ensembley

[@T0tenkampf]

Very cool video showing all the parts and how it goes together, I wish all content creators did this. Too bad it isn't actually a differential, I got excited there for a minute because that is what I'm looking for.

[@BubbaB43]

If you were to get a peerless differential with the 1" axle I'm sure you can come up with something as far as putting the spool in the center of the two outer mounting plates because their spoil accommodates the drive sprocket on one side and the brake rotor disc on the other. The only issue would be the the width, of course it's a bit wider than this one. I've actually thought about trying this idea myself.

[@T0tenkampf]

@@BubbaB43 yeah I think that's worth trying!

[@brianb-p6586]

I agree - the title saying "differential" is the only problem.

[@robert5]

Use a Subaru R160 differential with Polaris rzr 1000 axles and turn the motor side ways and bolt on a sprocket to the front of the diff and use a jack shaft across the rear to get power from where the engine clutch goes back to the front of the Subaru diff. Subaru cv joints have the same cv ball spider as Polaris rzr 100 cv axles. I took the Polaris axle slid off the ball spider, slid on the subaru ball spider so it uses a Subaru inner cv on the Polaris axle. I used all Polaris rzr 1000 axles and suspension because it is strong, cheap and easy to find on ebay. The subaru ball spider does need a tiny but of grinding so the splines go all the way in and the retainer ring fits but that can be done with a hand held die grander. I did use my lathe to do it because I have a lathe. The huge cool thing is the splines are the same on both and do slide together, that is awesome. The Polaris axle stays Polaris on the outer end and Subaru on the inner side. Fankin-axle, lol. The Subaru diff I found in a junk yard is a 4.30 ratio with viscous posi traction, I got lucky finding that as that was exactly what I wanted. Most of them are just open diffs like you want so that will be easy to find for you. Most are not 4.30 ratio but if you search you can find a chart showing what Subaru diff ratios there are and what the code is for them that if painted on the diff case. You can adjust over all gear ratio with your sprocket going from the jack shaft to the front diff chain. I am using a 500 Polaris snowmobile motor so i used a snowmobile clutch and jack shaft. All easy to find fairly cheap stuff. Yes the Subaru diff is a bit heavy but not to bad and it is totally bullet proof and can take well over 200 hp, so, your never going to break it. That is what i wanted as eventually I am going to find a big 150 hp snowmobile motor. The other nice thing about doing it this way is the carbs are on one side and the exhaust on the other, not in the front/rear. It is hard to route a huge 2 stroke exhaust around from the front of the motor. When I actually put all this together I will make a video showing how it all works and publish it. I love what JD and KJ racing are doing. I am a welder fabricator and machinist with lathes and mill etc but I am going to buy the KJ racing cross kart plans as it would take me years to figure out what spending 100 bucks on plans can get me up front so why not benefit from KJ and JD's experience.

[@dooby1445]

@@robert5 Thanks for sharing

[@kable698]

That is so awesome!! wish I would of thought of this a couple months ago sure would of saved a lot of headaches hunting down outlaw parts. Definitely want to know what you did for uprights

[@HobbitHomes263]

I just go to the local motorcycle junk yard and buy a rear wheel. I cut the hub out of the wheel. It has a brake disc on one side and a sprocket on the other side with bearings in between. I usually pay $10 to $20.

[@liamcondon225]

How do you set up for axles?

[@liamcondon225]

Can you send more information

[@tjrizvi251]

Yo hold up. That's actually a brilliant idea

[@wlightning07]

awesome spool thanks!

[@scottd8097]

Great work. I love it.

[@gonracn]

Thank you for posting!

[@bluejayfabrications2216]

This is good I like this design 👍

[@felmi5032]

Thanks for this great video:)

[@jaysunkreuze1466]

Way cool. This will make 4WD front and rear Independent suspension stupid easy.

[@jdsgarage701]

That's exactly why we made it, to help other builders out.

[@johnconnors4127]

Very very clever, I love it

[@brianb-p6586]

I assume that the boss on the Miata's inboard CV joint and matching recess in the final drive output flange mentioned @6:52 are there to centre the assembly, so that the bolts only need to retain the assembly and transmit torque, not to locate the parts coaxially. Using a flat drive flange and spacer leaves the bolts centering the assembly and makes bolt hole size and location critical to the balance of the shaft. If this is a locating fit, ideally the flanges would be thicker and machined (on a lathe) with a recess to match the CV joint boss.

[@tattoosbyjoe216]

Great stuff

[@CroutonRob]

Good work

[@aramchacon9256]

great content very helpful

[@terrybonitatibus24]

Much easier than the KJ Raycing hub.

[@overbuiltautomotive1299]

nice keep it coming

[@Jim-gi6ov]

Light simple well built

[@Rikasso66]

NIce thank you for posting.

[@prplezard]

Thanks! There is a mention of Polaris hubs to fit the axles. Can you go in-depth more with that?

[@JermaineLeeBlueprintAuto]

nice work

[@rogelioramos003]

awesome!!!!

[@MotoKingWOT]

I like how the guy behind the camera whispers to tell the people they are "brand new" lol

[@averagemanfabrication]

This is awesome

[@Traderhood]

Excellent!

[@williamgarcia9751]

I need this!!!

[@abels_04]

Simple and effective

[@DS-rj9db]

Thanks for the info. Videos are Awesome!!! Keep up the good work...and yes would like to see more videos!!! Also you made the Sprocket side large enough for the CV half Shaft and sprocket. The other side was just large enough for the CV joint only. Would the laser cut plans for the Brake side include enough room to attach a disk brake? Thanks...Keep up the good work.

[@jdstremi]

On our original design we were going to make the brake side big enough for a rotor but since we used a snowmobile engine the brake caliper is built into the chain case so only made it big enough to fit the cv axle.

[@dannyc6656]

OMG THANK YOU!!!

[@TylerBrown-wq8hs]

Any way to open up the inner diameter of the sprocket mount and brake mount to 2” for the x series weld in hub? As I don’t have the means to change the file

[@laynelommen9460]

Very cool. Thx.

[@2gnospam]

Nice!

[@PeterRistine]

Can I run this with different length axle? Mine is about 1 ft

[@clea7799]

I liked it

[@tonytowhitch]

Hell YEAH!

[@DoubleBogeyBaker]

Do you think those chain tensioner plates are to thin? I remember my four wheelers having the same type design almost but they were thick. Almost 1/8” thick iirc. Either way that spool looks killer!!

[@ChevyGuy70]

Will this be able to hold up to a 100hp engine?

[@DualTasticToday]

Nice

[@stevenpleasant5834]

Hi there real nice center spool I would like to buy a set of those bearing slider plates at a later on time nice build. also are you going to build the wheel carrier too and show that part and offer it to.

[@jdsgarage701]

Wheel carrier is in a separate video. We do not yet offer these as there are many possible sizes but we are working on something.

[@pugnaciouspete]

Can you clarify on the key stock, was it square and it was machined down? I was looking at the link you provided and it looks square.

[@jdsgarage701]

It is square keystock. We bought it as is and cut it into segments. No further processing.

[@RDAUGIRD]

Maybe you could edit the title of the video as this is a spool not a differential. Still a nice job.

[@victorblack9006]

Any way around using the keyway? Weld it in maybe? Without a mill how do u cut the groove for the keyway

[@jdsgarage701]

I don't have a mill either but I dropped the shaft off at a local machine shop and they cut it for like $20. You can weld it but then you would be screwed if you ever had to take it apart. Alternative way just buy a shaft with keyway already cut. I've also seen people cut a keyway with an angle grinder with limited success.

[@bdubb650]

What brake disc and caliper are you using on this hub assembly?

[@jdsgarage701]

Check out the engine video we talk more about it. We never put one on the spool we actually used the rotor and caliper off the sled and mounted it further up on the drive train.

[@bubbaflook8230]

I like this idea but what about the brake rotor? Are there any provisions for that?

[@jdsgarage701]

If you watch our other videos we explain how we did the rear brake. A brake rotor can be added by making two of the flanges that the sprocket mounts to and just using a rotor on the other side.

[@vintagetintrader1062]

How is this holding up, I’m about to start building one but using 50 industrial sprockets (same as 530 sprockets) so I don’t have weld misalignment issues

[@jdsgarage701]

Haven't had any issues whatsoever

[@juanksamaya3564]

I bought this kit along with the 1 1/4 bearings and 1 1/4 keyed shaft and it’s too tight to go in almost as if it’s gotta be pressed what am I doing wrong ?

[@jdsgarage701]

Sometimes keyways aren't cut properly and filing the keyshaft down is necessary.

[@stevelamson7442]

Awesome ideas. My only concern is the 1 1/4” axle key way. Is that strong enough to hold the torque?

[@jdsgarage701]

Yes, we have another kart with around 100hp and a similar setup and have had zero issues. You have to get high-quality key stock (link in description). This is also the same kind of key stock that 200hp sleds have on the secondary clutch. If you get some made from chineseium it will shear right away.

[@Ratkill9000]

Also helps to have key stock that runs a decent length of the shaft. I've seen 1" round stock with a key way work well with 60hp, only after it had failed due to only having just enough key for a sprocket hub. Once it was replaced (the key had messed up the shaft) with a new shaft and longer key stock it held up. Just need to run locking collars to help.

[@sheets8277]

What if you did away with the key way and used a 1 3/8” 21 splined shaft and splined hubs? Of course I would use 1 3/8” bore flange bearings, but you think this would be a bit stronger?

[@stevelamson7442]

@@sheets8277 if you could source them,they would be very tough.

[@goodoldtimesanderson3974]

How much for the whole set?

[@tedahn3539]

what size chain are you using? 428? The sprocket link is dead. What is the teeth count, please?

[@jdsgarage701]

It's a 52t 530 chain sprocket.

[@tedahn3539]

@@jdsgarage701 Thanks!

[@cerbie3]

You mention there would be a link for the laser cut plate files. Can you please share those. I don’t see the link. Thank you

[@jdsgarage701]

www.thingiverse.com/thing:4902515/files Scroll to the bottom of the page, to see all files they will be .dxf files. Also check out the last link in the description if you need someone to cut them out.

[@sepedius]

Great design, Im 100% going to copy this. Just wondering if there is any chance for those plates to slide outwards?

[@jdsgarage701]

It can't happen if you install the locking collars correctly. Also the cv axles don't even have enough plunge to allow it to happen either.

[@sepedius]

@@jdsgarage701 yes shaft cant move anywhere thanks to those locking collars, but what stops your plate sliding out just a tiny bit and messing your chainline? Is there a setscrew in those weld on hubs?

[@harryconover289]

it deems like lot of work jou chain adjester i am uawd two scwers

[@stefancveticanin4522]

Great solution! Thanks for sharing. Would you be ok with me recreating this as a CAD model and sharing online? I would keep reference to your video. Greetings from Serbia.

[@jdsgarage701]

All the files are already avaliable in the thingiverse link in the video description for this version. We will be releasing a new version soon, that we will be charging for that includes brake rotor and caliper.

[@tonytyree1913]

What year miata axles are you using?

[@jdsgarage701]

1993

[@khalilhollins6736]

When’s the restock lol

[@g.wes.3906]

Has anyone figured out a brake setup on the spool itself?

[@jdsgarage701]

Just released a video about how to modify the flanges to fit whatever brake rotor or sprocket you want.

[@g.wes.3906]

@@jdsgarage701 that is awesome news. I was starting to look up the prices for lathes, 3d printers, parts design software. But I will happily support you guys who are doing a lot of the hard work.

[@Mainekarter2004]

I wish someone would build complete weld in rear IRS system..

[@jdsgarage701]

Coming soon...

[@Mainekarter2004]

@@jdsgarage701 be happy to be first in line!

[@lancesavageau8698]

Im impressed, live in Glyndon, mn. Would like to talk. Have a couple of carts.

[@jdsgarage701]

Check out the channel page on a PC to view the email for some reason it won't show on mobile. I actually live 10 minutes away from Glyndon.

[@JermaineLeeBlueprintAuto]

So i guess its inch and a quater flange bearings

[@orvilledickens9342]

What would it cost for you to make me one?

[@jdsgarage701]

Send an email to the channel (in the description) and we can work something out.

[@henryventry8762]

Can i buy that from you fir 100?

[@jdsgarage701]

You can find it here. jdsgarage.bigcartel.com/product/cross-kart-spool-kit

[@diegocadena1376]

If he continues to hit with the sole of his hand, he will get carpal tunnel, try to hit with a rubber mass or a tree

[@npickart]

Dont ever use washers when bolting an axle to a spool like this. Get the hub relieved at a shop or if you have a lathe, its easy to do yourself. Washers are not a tight fit and will inheriently slip to one side introducing wobble in your axle, once it starts wobbling. It will only get worse and fail. DONT DO IT.

[@Jared_7071]

Just get a tight fitting washer, it’ll be fine

[@xod7861]

Cheap also

[@brianb-p6586]

Good for what it is intended to show, but why does the title say "differential" when it is not a differential? Use "final drive" or just "spool" (which is what is in the description and audio), not "differential" since that is not what it is at all. I know of someone who is considering a buggy based on the KJ Raying crosskart design but should have a differential and that's the only reason that I chose to watch this video.

[@TheCidiot]

Where does the rear brake disc go?

[@jdsgarage701]

It went on the chaincase for the snowmobile. We remade the spool to accept brakes. In our newest video.

[@TylerBrown-wq8hs]

What sprocket is used? Is it a standard sportbike or custom?

[@jdsgarage701]

It's a Suzuki gsxr sprocket

[@TylerBrown-wq8hs]

@@jdsgarage701 thank you sir and what about the brake?

[@jdsgarage701]

@@TylerBrown-wq8hs Reused the brake on the chaincase from the sled.