25+HP Predator 420cc Hemi Everything Billet Build ~ XXL Go Kart Engine

In today's video I take a stock 420cc hemi predator engine from harbor freight and show how to build it to 25+ HP - billet valve cover, billet 1.3 ratio roller rockers, chromoly push rods, billet side cover, billet rod, .308 cam, billet flywheel, billet killer bolt covers, 34 mm mikuni, msd style coil, 65lbs double valve springs, and block, head, and piston Cerakoted. We put the engine on the gravy bones kart. We give it a first start and a few revs. Subscribe for the next video of testing!!!
Parts Used On This Build -
420cc Predator Hemi - bit.ly/3qHtMdR
Stage 2 Performance Kit - bit.ly/33EiRpS
34mm Mikuni Kit - bit.ly/2PeTnL1
Muffler - amzn.to/3xZTOQ2
Top Plate - bit.ly/2NDP1fT
Chromoly Pushrods - bit.ly/3EMdhVY
Billet Rockers - Coming Soon
Billet Valve Covers - Coming Soon
Billet Piston - Coming Soon
MSD Coil - Coming Soon
Killer Bolts - bit.ly/2Fg1pAG
40 Series CVT - bit.ly/2Q6mjG7
40 Series CVT 2600RPM Stall - bit.ly/3kPFDEd
Billet Side Cover - Coming Soon
Head Studs - Coming Soon
Metal Head Gasket - Coming Soon
Starter Ring Gear - Coming Soon
Check Valve - amzn.to/3yeXmLJ
Tools Used On This Build
Maxima Assembly Lube - amzn.to/3xQJdqI
3/8" Torque Wrench - amzn.to/3ixDZbg
1/2" Torque Wrench - amzn.to/36pwLx2
Piston Ring Grinder - amzn.to/2ROOvOr
Ring Tool - amzn.to/2sp60tT
Ring Compressor - amzn.to/2YITNwr
Plasti Gauge - amzn.to/3CzouYu
Soft Jaws - amzn.to/3q3aQZ5
Merch & Events - bit.ly/33YbmtO
Check Out Go Power Sports for all your Go kart needs! bit.ly/2viX9vP
Parts & Tools used on the channel - amazon.com/shop/redbeardsgarage
Quantum Machinery- Siegmund Welding Table - bit.ly/36PHm6G
- Nargesa CC60 Bender - bit.ly/2xWDVxj
Prime Weld Tig 225x - bit.ly/2EbSIqK
Prime Weld MIG180- bit.ly/2Q44l5V
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Red Beard's Garage
P.O. Box 572
Sweetwater, TN 37874
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*********Disclaimer*********
Please do not try to re-enact or recreate anything you see in these videos. We are trained professionals. Red Beards Garage does not take any responsibility for injury's created by doing so.
#RBGKarts #RedBeardsGarage

[@CJLeTeff]

RB you’ve got the best, ‘How To Build’ videos for small engines! 👍👍🎉🎉🎉🎉🎉🤘🏻🤘🏻

[@OppoOppo-cn5no]

ผมอยากชื้ออะไหร่จากคุณ

[@kennethlizarondo7699]

@@OppoOppo-cn5no hjbbbZkhgyhs vb

[@brettmoore3194]

Generator

[@andriyanto5112]

11

[@dashlamb9318]

Have to agree. Straight forward, to the point, and detailed.

[@RedBeardsGarage]

What you would put this engine on if you had it??? ⬇

[@brianrhubbard]

This time of year, it would spend a few days on the garden tiller.

[@tlctinkerin5196]

I have a GY6 go kart I’d swap that on!

[@davidschumacher52]

It would be fantastic in my club car golf cart I'm doing a engine swap on!

[@WOMANIZERJERRY]

If I had this Engine, I would sell it and build 2 - 212's

[@chuckb9867]

Use it for a Mud Motor on a boat if you know what that is it's like an engine on a stick with a propeller

[@jamesroberts1800]

Having been a race mechanic for *more* than a few decades I have to compliment you. Nice vid, solid camera work, clean and concise directions/instructions. Not too much or too little of anything, well done. Now you just need an old fart like me to show you how to port a 2 stroke so it screams, I have my tricks :) but they are my tricks and I choose not to share too much. Hey, a guy has to have a few secrets, right ? I learned from the old legends like Terry Drake (Drake Offenhauser) and Louie Unser (Al Unsers brother, Bobby's uncle). Kinda surprised I haven't seen you mess with a Zenoah engine or two....or a bigger Honda twin like a GX 690 or sumpthin ? From what I've seen, not too bad of a shop, still need a few things, but it appears you're getting there.

[@robgto7051]

its not a 2-stroke

[@jamesroberts1800]

@@robgto7051 duh ?

[@sagenbabin8786]

I can confirm The valve spring compressor I used on my klx 110 and a friend used it on a Honda foreman 500 it works perfectly

[@leoarc1061]

How many hours can these small engines do before a rebuild (approximately)?

[@sagenbabin8786]

@@leoarc1061 idk aproxomatly but my bike is an 03 and it has the factory bottom end so it’s 21 years old I’m gonna rebuild it in a month because I have an oil leak. But the reliability just depends on the maintenance I run the shit out of my bike tho it’s bored out with a race head and a rev box and it’s run this way for 2 3 years

[@hanapilibang6163]

I really like seeing the results of the resin

[@getitdunnoutdoors8584]

Please do more builds like this. I would love to see a 420 or EC carburetors 460 road to horsepower dyno build.

[@sibirty]

I’m getting some serious “Trucks!” On HotrodTV in the 90’s vibes from this video!

[@Thewatson77]

Anybody would be absolutely thrilled to rip this beast! Great work as always guys 👌🏼

[@DIYWilly]

Great video as usual but wish you would have talked about installing the starter ring gear on the flywheel.

[@RedBeardsGarage]

It simply bolts on.

[@DIYWilly]

@@RedBeardsGarage Did you have to drill the flywheel. In your parts line up I saw the ring gear separate from the flywheel.

[@jessehawks1849]

Best videos for learning and i seriously hope to have the common knowledge of you one day

[@brighambaker3381]

What's crazy is that your predator 225 from the other video makes over 20 with just over half the capacity!

[@lizzard7473]

I need a couple thousand dollars to burn. That engine is freaking nice! The white shroud with the gold, and the black block with the billet and gold, man, that is an awsome looking engine!

[@garyfraser8584]

Awsome motor. I just bought a 420cc predator today. I will be doing some modifications in the future. This is a fantastic build I love all the Billet parts

[@RedBeardsGarage]

Enjoy it

[@garyfraser8584]

@@RedBeardsGarage if I put a flat top pistons in place of the dished piston on a 420 overhead valve non Hemi head how much will it raise the compression

[@trumpfancardanostakepool4737]

Love watching these engine builds. That thing looks sweet.

[@samsgarage1716]

Wow that’s amazing.I can’t wait to hook up my 459cc engine.Great video.

[@CODOutdoors]

That motor sounds so angry, love it! Great video!

[@kenyatasims6991]

Man that engine is sick‼️

[@Dlokey4315]

Fantastic build video RB great video shots tips and tricks to get the most of the engines performance. Your the king of small engine repair and fabrication. 🤘💀 Ride Fast!

[@jhonsoliejhonsoy9434]

I love your work, I really amazed If I have a money i buy engine like this , some day🙏

[@mphjunkie5457]

My man this on a small to med surface drive would be the baddest thing that side the Mississippi 🤙

[@MrCarmelo1959]

Hi Red me again forgot to mention I’ve been rebuilding my Kawasaki mule like the one you did putting in a DuraMax 715cc?? Man I just got a deal on a DuraMax 16hp 420cc and I’m dropping in my mule never never have I done this before but I’m going to try it myself watching your videos have inspired me in growing a set and getting it done there’s too many people out there who charge too much for doing this work my mules been sitting for more than 2 years bought it with a bad motor but you confused me talking about the dif going in reverse changing it around replacing it with a golf cart dif….got to go back and watch that video several times to understand what you were saying anyways wish me luck later brother Red😊😊😊

[@boycabatomixvlogs]

Great engine ..maybe this is good to install to a small boat ..good for fishing adventure...

[@CuzznDave]

Great vid even though I know this it was still so good I just kept watching great job. Master Craftsman make it an ART. 👍👍😃😃🥰

[@mphjunkie5457]

These would be sick ass mud motors

[@fftbrantley]

Rewatching this as I’m building a gx390 stroker and I noticed at 11:28ish, it sounds like someone ripped a big one or your shop has barking spiders 😂😂

[@DarkWolfForza]

Lol

[@brandonhewitt2386]

I was wondering if using that coating on the block would cause it to have less heat transfer. Being that it is air cooled you want to get the heat out of the engine quickly as possible. I love the build & as usual you've shown me some things I didn't know.

[@duanehenicke6602]

I was thinking the same.

[@johnmcclain3887]

The best way to get heat out of an engine is to minimize heat transfer into the head and block, and ensure the highest exhaust temperature. Free flowing exhaust carries the most heat, allow it be cooled by contact with the block/head area, lowers the heat, lowers the thermal expansion of the exhaust gases, slows the movement of gas volume, so it more time/contact with the block and head port. Porting is mainly about keeping an even cross-section to minimize "volume change" in the intake charge, to keep low velocity flow smooth, constant going in, and keeping the exhaust cross-section change minimum, to minimize heat transfer as the rate of flow changes. Slight change in port volume changes velocity of flow, allowing more energy transfer equally more heat transfer from the exhaust into the block.

[@carsonhendee919]

He said on a livestream a few weeks ago that the type of coat got he used is supposed to help expel heat

[@joshuaphillips1867]

Effective insulation for an aircooled engine....coat or paint the block and head. Basic math and set of calipers will be leagues ahead of plastiguage.

[@maycoamaro3346]

Parabéns ficou muito bom seu trabalho com quantos HP ficou depois que você trocou as peças

[@jondavidmcnabb]

1st. Excellent video and great tutorial. Honestly the best build video on KZbin. Love seeing you make video like this!!! Have you ever considered building an air cooled outboard motor for a boat? Either a mud motor of just a re-power of an old clapped out 2 stroke? I bet you could make a really interesting video about that.

[@HoardFarms]

I'd put that in my drag mini bike on my channel if i had that motor

[@letrasmais4215]

in Brazil we do this type of preparation in a motorcycle engine like the Honda cg originally 150cc and with adaptations it reaches 500cc but the most common is with 270cc, also very common with Honda CBX 250cc Twister engine is the most common with 450cc.

[@117moose]

Thats interesting about the ground strap.

[@seansysig]

I like the thump of that cam. I’m 6’1” 280 lbs. curious what a cart like this would cost?

[@ridingdirty8897]

You can also put more timing in that buy using a off set fly wheel key. But I'm sure you know that. Most people dont

[@BuildBreakFix]

Question why exactly did you cerakote the piston?????? Never heard of that before ! Would this help stop cold seize in cast iron jug /aluminum piston build to some extent?

[@blainethompson6510]

So informative Question is the coating “polish” to allow flow in porting or is the inherent in the coating?

[@MrCarmelo1959]

Hi Red you always amaze me how talented you are and knowledgeable you are you’re a beast builder. Can you tell me if you can rebuild one and ship it out to me is that at all possible..just asking because I know it would be great if you can thanks always appreciated your videos brother Red👋👋👋

[@deandee8082]

you wedgied that seal out with a screw driver, will it be reused ? crazy how easily it came out as well, seems always have to reach for the dremel, that motor did not look to used and abused tho, may have helped?

[@donaldrush5760]

How do you change the battery, with. out the charging. coils???

[@jimhernandez5175]

how much money in parts including engine

[@garyfraser8584]

What kind of compression ratio did you end up with on this motor with the flat top piston? Also was the head milled at all?

[@juliusgreen7495]

Great job guys great video

[@tristanmcnabb2741]

Allsome work that looks really nice 💕🌟👌😁🎉 from cruzermans inventions 😁🎉🌟

[@SuperBigdanno]

Please explain how the extra ground strap from the coil to the head helps spark.

[@RedBeardsGarage]

Normally the spark plug gets ground through the head and on through the block to the coil. Grounding the coil to the head instead of the block helps a better transfer of power.

[@SuperBigdanno]

@@RedBeardsGarage thank you

[@fishsticks88]

Basically a $2500 motor I like it

[@tjtj3027]

I'd like to know what clearance work was needed for the cam.

[@fatboyy11]

I’m wondering would this fit on a rascal mini bike frame

[@leoarc1061]

Can anyone tell me how many hours these small engine builds will do before needing an overhaul? Many thanks.

[@justiningram2380]

How much issues do you have with the valve seats I run these motors on my generator and I have hell with the valves always have to readjust the valves

[@roelcervania2319]

I injoy to watch your video sir'how to build a powerful single piston engine? But how many cm"the diameter on your bore sir? Sir

[@hacxer8424]

Build one for a mini bike

[@gonracn]

That is gorgeous

[@Wrekamega]

Hey Red, Man I’ve been watching your videos for a while now and the only video I come back to is this one. By chance do you have the links for the “coming soon” parts on your links list?

[@piefum1]

I don't understand why RBG cerra coated the block. It just seems counterproductive to insulate the fins. I get why the coating is on the inside, but like still.

[@Popcultpistons]

SWEET! Was this ever put on anything?? Cant find other videos with it!

[@z1berzerker]

3rd time watching this video 📹 👌 Great content

[@dennymedia]

Good job👍

[@SpencerVillanueva-k7u]

What material are the clear hoses made out of?

[@chandlerknight8623]

What are you using for a fuel pump? Did you go electric or are you running a pulse pump? Also are the hoses from the valve cover to the motor to equalize pressure?

[@darrinscoilsclouds1498]

What is the large thing hanging off the end of the connecting rod end cap?? Summon please I must know?!?!?!?!

[@williamworth2746]

From one bald red beard to another nice build

[@wags9777]

1300.00+ for the listed parts. still quite a few parts not listed. I could pick up a yz125 motor for that and there would be nothing you could do to this hemi to beat me and it would sound cooler too.

[@RedBeardsGarage]

Well you buy that engine and I will keep on building these. Anyone can buy a engine. The fun and excitement is building it myself and getting to have fun with the results. Everyone is different.

[@Hyprmtr]

What was that noise @11:27?

[@Just3adventures]

That thing is SICCKKK!!! 🔥

[@charlescole-p9v]

Now if you could do altitude compensating fuel injection for my ultralight.

[@Bighemi82]

What kinda socket did you use to do the rod bolts

[@garyfraser8584]

S0 how much hp did it end up making? Im doing a similiar build with a440 stroked 420 non hemi with ported head 40mm and 34mm valves 306-0411 cam flat top piston .027 head gasket billet everything arp studs for everything.34mm mikuni flat slide carb and custom header.

[@priestblood]

It would have been cool to see stock hp and torque and compare to kitted out engine.

[@kotborka]

А почему ты не применяешь гайковерт для затягивания гайки маховика?А вообще очень интересные доработки по таким двигателям.Приятно смотреть на хорошую,качественную,работу).

[@Jalen_Knight8526]

It has to be torqued to spec for safety reasons lol.

[@ecord87]

Your video's are awesome! If you had to choose between the Duromax and the Predator what would be your choice? Which one do you think is better built?

[@Jalen_Knight8526]

He has already said he likes Duromax because it is around the same price and way higher quality.

[@jsmalone]

Can the 420 motor charge the battery while its running?

[@predator_boiz336]

Why exactly where you happy that it was a hemi 420? Are the differences about the same as the 212 hemi vs non hemi?? Thanks for any info, I’m wanting to get me a custom minibike frame made so I can run a straight chain on a 420

[@justintroy9827]

Would you recommend an engine swap like this 420 over the 459 in a ezgo golf cart? Seems like I’ve been seeing a lot of small issues popping up in the 459.

[@mikerammelt2420]

Hi whouldn it be a good idea to balance everything.

[@adamideus9222]

KZbinr robot cartina could use that motor for his Honda insight

[@garrettrogers9303]

What about the flywheel and ring gear

[@brianrhubbard]

A very high quality video

[@kristopherkendall4304]

How much would you charge to build one including all parts

[@Zonards2012]

Hope u bro come%visit here in philippines , and test ur engine in my racing boat Phil . hehehe

[@carlosison4806]

Where to buy all the billet parts so that I can do the same to my engine. Thanks

[@steveschnuck2457]

Straight beast. God bless

[@kalifetv1949]

Were the balancer ?

[@WillnStephnum1]

Ok you guys got it great info. Hey what about turkey bay it's says rain y'all still up for it?

[@RedBeardsGarage]

Yes sir. Rain or shine we will be riding

[@WillnStephnum1]

@@RedBeardsGarage great we gonna try to be ready . Had 4x4 go out on my atv. If not 2 whl it is . Got a few days left.🤞 Oh we live in Paducah but visit lakes alot. Do y'all know where the camping spot is yet. I know some good of grid or on either way. Love LBL!!! Oh have y'all ever been to Whrights Area 252 in Bardwell ?

[@doitfordale7599]

Hey man really great video!! I’ve watched all your videos and learned so much and I greatly appreciate it man. So question , what is that bigger black hose you have running with your other vacuum hoses coming out of the top of the side cover? Also do you have a fuel pump on there?

[@ruicunha103]

by magic, in the end of videos those valve cover lines appear not explaining what is theyr function.

[@andrewbodine5663]

What would cost be to buy the stock engine and all the upgrade parts?

[@TacticalTinkerer]

I know they kinda get covered up, but could a guy dress up the top two head studs with an acorn nut? If you electroplate or powdercoat, you could even get custom colors...

[@RedBeardsGarage]

Yeah there is also killer bolts for this as well. I just used studs instead.

[@donaldrush5760]

The Billet Flywheel Don't have the inside magnets to charge the battery!

[@finishingfinishing1543]

Amazing job 👍

[@christophermcmahon7920]

What is the valve to piston clearence? I am doing g the exact build and only have .025 intake valve to piston. Maybe want to check that before people build a motor that gets destroyed right away

[@dashlamb9318]

Can you show a rebuild on a Subaru EX 21 and a Honda GC 190? Both are currently installed in Mokai jet powered kayaks.

[@zadgill]

Love the videos. Very informative. I have a question for you. I’d like to put a modified predator 420cc engine into a Honda Navi. Is this doable?

[@DarkWolfForza]

This would work fine actually :) just make sure ya got a decent gas tank for it.

[@dongreene2546]

I put a 459 predator on a yerfgog, series 49 torque converter, 20 inch tall rear tires, reverse gearbox. 8 tooth, #40 on gearbox, with a 54 tooth on axle, my belt slips, and gets caught in the driven pully and breaks the belt. It worked ok with a 60 tooth sprocket. But it's really slow. Any ideas???

[@K_M_M_G]

Isn't the aftermarket piston used not meant for a hemi? Look at the valve relief cuts at 3:23 vs 13:06 ....

[@WOMANIZERJERRY]

It is a Hemi 🤣

[@K_M_M_G]

@@WOMANIZERJERRY Read the comment again… “not”

[@computerrusak7223]

What is the size of the pilot jet and main jet?

[@GREGDICKINS]

Can I ask why the four clear tubes from crank case to rocker cover?

[@DarkWolfForza]

He usually doesn’t explain them

[@subursuburkodim8821]

I think over strong spring injections

[@specificocean270]

you should build a cr500

[@jaygouy7599]

Stupid question are any of these parts compatible with the 459? I wish I would have found this before I got it over the 420 😖🤬.. I like the videos and appreciate your humor sir!

[@Bayareaminibike]

Yo @redbeardsgarage can this engine take race Fuel? And also need an update on the parts list. I’m trying to follow this build on my 420 predator