Honda GX390 Big Block Swapped Tao Tao ATK125CC Go Kart Buggy

[@slimyelbow]

Nice buggy. I have done the same thing on one of those manco 606s. I have billet flywheel and rod. No governor and 50lb springs. That's the only mods. 10t to 60th with 20 inch tires and so far top speed is 44. Love the videos. New fan here. Also have a daughter who rides.

[@bstarnes514]

Thank so much for watching! I really appreciate that! I went and checked out your vids! That hillclimb looks like fun... I'm unfortunately confined to the Circuit De La Starnes beside my house lol... Anyway, good mods on your motor! The only things I've really bought for my motor have been 35lb springs and a 34mm Chikuni carb... there's been more in house head work, porting/polishing and custom fab work than anything else.... Gearing starts with a 40 series CVT with a 10t on the jackshaft, 60t axle on 16" tires... Mines not as fast as yours but damn does it take off lol!! Anyway, yea my daughter loves it... she has a little 50cc quad that she rips around with me as well...🤟

[@Witness_Me-j4q]

Ohio here... Awesome setup !!! Just got that motor for my offroad !!! Cant wait !!!

[@butchybaldwin1831]

nice work brother! awesome!

[@bstarnes514]

Thank you! I appreciate that!

[@carlossolano5003]

What size sprocket? Where did you get it

[@bstarnes514]

60t sprocket for #40 chain... got it from ebay.

[@carlossolano5003]

@@bstarnes514 thank you ! I got a Tao Tao 125 cc it’s my kids . Eveytime my kid rides or something breaks . I’ll be swapping a Honda gx motor on it! Just gathering all the parts ! Thanks for the reply !

[@bstarnes514]

@carlossolano5003 You got it man! Good luck with the build! The GX390 will definitely take it from mild to wild in a hurry lol. 🤘

[@carlossolano5003]

What center bore for the sprocket 2” ? Ordering my parts today

[@jawnsr]

i just got one of these as a project and its been sitting for 10 years... i dont know much about motors and i hope our motor isnt seized haha ours is a beater the steering doesnt work so i think it needs a new rack

[@bstarnes514]

Hey what's up! Mine was in very rough shape.... it had been sitting outside in the mud for a long time.... my steering was stuck solid.... I just kept soaking with any penetrating lube I could get my hands on and eventually it freed up.

[@jawnsr]

@@bstarnes514 mine is doing the same thing! it's stuck solid. ill try that out!

[@bstarnes514]

@@jawnsr yea man give it a shot.... also the steering shaft one mine was stiff as a board too.... I ended up cutting it off and making a new peice with lawn mower wheel bearings...

[@jeremyshea8055]

Holy shit. I bought a beat down cart to mount this engine that i got on a whim to.... Completely random so im looking to see what kind of power it can make. Your video was the first to pop up. Would you believe you have the exact cart and motor in the exact same condition as mine as it was bought! I think i might have found my new channel for this project!

[@jeremyshea8055]

Im dumbfounded

[@bstarnes514]

Hahahaha dude that is awesome! I can feel your excitement through the text lol.... Yea man it's a good platform to build on plus the GX390 kicks absolute ass too.... My kids and I love this Kart! We named it GOAT. Dont ask why.... that's my kids for you hahah! If you have any questions as to how I did anything please feel free to ask! 🤟🍻

[@bstarnes514]

@@jeremyshea8055 Hey looks like I'm your first Sub too! 🤟

[@jeremyshea8055]

I really appreciate that man. I knew the combination of the 2 has serious potential but the way you explained it really drove the idea home! Im going to be using your motor mount/tensioner trick for sure. One mans over engineering is another mans inspiration. Im not much of a videographer but im going to record as much of the build as i can. Any critism or advise you might have is beyond encouraged. Thanks again dude!

[@bstarnes514]

@@jeremyshea8055 Haha thank you man I really appreciate it as well! I'm not a very good videographer either! I'm much better at building than videoing lol

[@Tampaboys]

Man that little cart must rip bud

[@bstarnes514]

Dude yes it is a true beast lol... 10t Jack sproket, 60t axle sprocket on 16" tires... Its geared for torque and acceleration! 🤟

[@BunkerBlog]

What's the top speed? What gearing are you running? Thinking about doing a big block off road kart myself. Was originally going to go the cheaper route with a built 212 but now I'm considering the torque of a big block.

[@bstarnes514]

What's up man! Thanks for taking the time to watch! So I've got it geared pretty low. I have a 40 series CVT/Jackshaft combo with a 10T sprocket coming off that jackshaft to a 60t axel sprocket on 16" tires... I'm also using #40 chain.... I do more trail riding with it so I wanted it to have more torque and acceleration rather than overall top speed... That combination with the big block GX390 makes for a fun ride! I like the 212's but I REALLY like the big blocks! The engine has also been modded to boot.... I dropped the governer completely, installed heavier valve springs, mild port and polished on intake/exhaust ports, shaved head about 15 thou, 34mm Mikuni Carb w/Jetting, custom tuned length intake manifold to make peak torque around 4k RPM, and 1 1/4 custom exhaust with homemade rebuildable glasspack muffler.... Sorry for the winded response lol... I love this thing and will talk about to anybody willing to listen! 🤟

[@BunkerBlog]

@@bstarnes514 I'm doing my first off road kart build and I'm trying to decide between a 212 and a 420. Like you said the big blocks have tons of torque but they are heavier and way more expensive to modify. The small blocks are light and way cheaper to mod but they also have less torque. I'm really looking for something to do some high speed trail riding in (sort of rally style). What do you recommend?

[@bstarnes514]

@@BunkerBlog Heck yea man! I like the idea of a rally kart! Something light weight, nimble and fast! However, I'd prolly still go with a big block though even though they are chunky....You can always lighten the motor by taking the electric start stuff off... I'd say my motor with the mods I've done prolly makes around 18HP/24ft.lb.... If budget allows look for a good used big block and go from there... At that point your speed will just come down to gearing.... But then again the 212 is much cheaper and will get you rolling sooner.... The main reason I went with a big block was because my Kart is bigger than a standard yard kart.... I wanted to make sure I was disappointed when I hit the gas lol.... So I guess my question is how big is your kart?

[@BunkerBlog]

@@bstarnes514 Its going to be as compact as possible, likely well under 400 pounds. Full suspension, 16" front tires, 18" or 20" rear tires. I can get way more RPM out of a small block and just gear it low, or I could get a big block with a lot of torque and just gear it higher. Aiming for 50mph with a lot of low end grunt. Like you said, don't want to be disappointed!

[@bstarnes514]

@@BunkerBlog Haha man that literally sounds just like the debate I had going with myself on what I should do... I guessed that my Kart probably weighed in that ballpark when I got it... If I run tires like that on mine it would give me more top speed.... Plus my Dad and I are car guys and He always says Torque wins races and HP sells cars, so I had that phrase rattling in my head as well lol.... I mean dude for a Kart that big I'd still lean towards a big block of some kind... Also I'm honestly not bias towards one or the other either... I freaking love small blocks for what they are... I also mod out 5hp Briggs flatheads as well... Anyway, are you building the chassis yourself?

[@stephenwicks6499]

What size chain would you recommend using for my gx390 cart build

[@bstarnes514]

I would say nothing smaller than 420.... I'm running #40 on mine....

[@techs2825]

i have that engine but it has 0 COMPRESSION... Any tips?

[@bstarnes514]

Stuck piston ring mabe.... What all have you already checked?

[@issakgomez3586]

Do you have a video actually driving it?

[@bstarnes514]

Yessir I do! Theres a RIP & Ride video on my channel!

[@tariqschmidt1413]

Hey I love it! what jet size are you running? What internal mods?

[@bstarnes514]

Hey what's up my dude! Thank you I appreciate that! So I'm running a 35 pilot and 260 main! However I think I'm gonna drop one size down on the pilot and up one size on the main. I feel like its rich on the bottom and lean up top... Anyway, the motor has stock rotating assembly. The mods are as follows... Mild head port/polish, Complete gov. delete, 35lbs valve springs, .10 thou head gasket, Champion HD 1.1 to 1 Rockers, Chromoly pushrods, Fresh bore hone and new rings, 34mm Chikuni carb, tuned length intake manifold, Honda variable timing ignition coil, 4 degree advanced flywheel key, 1 1/4 exhaust pipe with custom built glasspack style muffler. I'm running 10t jackshaft sprocket from the 40 series to a 60t axel on 16" inch tires.... She does about 38MPH and accelerates like a beast.... Your buggy is awesome man... just checked it out!

[@bstarnes514]

Just sub'd to your channel!

[@tariqschmidt1413]

@@bstarnes514 Thank you for getting back to me! And thank you I appreciate that! I'm on the hunt for jets tonight and I noticed my 34MM also came with a 260 / 35 inside and thought that was going to be to rich so thank you. So far have the vegas carts champion rockers, longer chromoly rods, 35lb springs, 260 cam in the drawer. Now have to hunt down an 8' mikuni cable.. uugh!

[@bstarnes514]

No problem man! I love talking about this stuff haha.... I thought my carb was going to be rich as well.... I bought 2 sets of pilots and 2 sets of mains from ebay and this is where my carb tuning journey began lol.... I'm thinking to myself theres no way this thing will need jets that big because the hole looked huge. It took me for ever to finally get the carb tuned right... I must have swapped jets out 20+ times lol...Also, I was able to mod my existing throttle cable to work with the mikuni thankfully.... I think the best mod I made so far was the variable timing ignition coil... Its like a CDI and gives you a range 20 degrees of variable timing.... I got it from NR racing! Man your buggy is awesome though man! I like how big it is. Mine is rather small... I literally wanna cut it in half and extend it 6 inches lol!

[@tariqschmidt1413]

@@bstarnes514 Me too! So after all the jet changes you ended up back at the stock 260/35 combo? Where did you set your needle? That sounds like a huge headache! people are so unhelpful with jetting size advice I've noticed so I appreciate you. How did you get your cable to work in the mikuni? Thanks! I'm loving it. It is based on the Kandi Spyder 250 lower frame, wanted to keep up with my friends in their Can-AM and RZRs and we live right next to 5K acres of logging forest with some rough trails and needed the height clearance. I have to say these gx390 based engines are night and day compared to the stock moped engines.

[@benbarkey8333]

I wanna put this engine on a mb200

[@bstarnes514]

Yea that would be insane! This motor has no problem yanking this go kart around lol

[@alexmichel2937]

@@bstarnes514 HEY Man i made sure to subscribe to your channel and like can you please do a ripping around the buggy i want to see the full capacity of it i just took of my 125cc engine off to install a 212cc but i want to see how it rips aorund first please thank you.....

[@bstarnes514]

Hey Alex I appreciate that my dude. There is a rip and ride video on my channel of the kart in action! Since that video I've made more mods to the engine and ignition system! Just so were on the same page this is a big block GX390! Shes an absolute animal lol...Also I have it geared for more torque/acceleration rather than flat out top speed. However, I did clock 33mph and it wasnt quite finished.... I'd say it'd probably top out around 40mph! In a nutshell it is extremely capable...

[@jesantospotter2737]

Im workin with a gx340 mb165 mini itskinda tight

[@bstarnes514]

@@jesantospotter2737 Yea I bet that thing is fun!!

[@mglando]

Hey do you have a Facebook or any contact info

[@highgatehandyman6479]

250.. nice deal