My Razor Dune Buggy Adult Conversion is Complete

[Bmr4Karts]

After getting my 5yo daughter an electric gokart I needed something I could ride around with here.

I was originally going to convert a gas buggy to electric and found a Mango Dingo 285 for a good deal. I then spent tons on a high power brushless motor, 96v controller, and 14 prismatic lithium ion batteries from a Ford Energi. Next I began to slowly realize this was getting out of control.

I aborted this plan and joined the Power Wheels Racing Series Facebook group. Here you have adults that build gokart chassis that fit under toy car bodies. They are limited to 48v and 30 or 40 amps. Most cars run between 15-20mph and the racing is competitive. Most of the racers use the ~$135 48v boma style motor and controller combo so I figured it should be good for me also.

People here recommended the Razor Dune Buggy and I finally found one for $75 after three months of searching. I had already bought a welder for working on the Manco so I began to make a motor mount for the 48v motor. I am still using the stock jackshaft but upped the motor sprocket to 15t from the stock 12t.

Besides the motor mount, I also cut and re-welded the top uprights so I could put half of the battery pack up top and the other half is where the two stock 12v batteries use to be.

The only other mod is a new thumb throttle with an on-off switch and voltmeter. I'm not running any kind of BMS, I use a hobby grade battery for charging and individual cell checkers with audible alarms when driving

All up weight is 84lbs which is far less than the just the Manco's chassis and wheels.

Top speed on the flats is ~17mph with my 200lb frame and it easily gets me up inclines. I have 40amp fuses coming from each battery with 10awg wire. Nothing is hot when I'm done, motor is warm but that''s it. The batteries have almost 20ah and I could probably drive for an hour before needing to recharge. The batteries are wrapped in foam floor tiles cut to fit and strapped to the frame with velcro.

Next goal is to add mud flaps over the rear wheels.

Next project is to buy another one and mod it with larger tires and a standard 35t sprocket setup.

 

[landuse]

Nice!!

 

[Bmr4Karts]

Got the 2 gallon bucket rear fenders mounted. Should work perfectly.

Also added some size comparison pictures. The second Razor Dune Buggy I get will have tires closer in size to the pink Lightning Bug and a slightly extended rear end to accommodate two motors.

 

[Bmr4Karts]

Update, no longer complete. I figured out how to put larger wheels on the back using some hubs from HF and some 4ply tires from ebay. Works great, but the larger diameter wheels slowed acceleration. I first tried the HF tires that came with the wheels but they don't last, wore holes in them doing hard stops.

On a FB group, someone mentioned using a different speed control with the motor, one capable of sending 50 amps and that it really woke the motor up. A few days after that I learned about the simple mod you can do to the chinese speed controller to increase it's output amps which is nothing but adding solder to the shunts reducing their resistance. So I did that and ordered a shunt with amperage display and now its pulling over 50amps going into the esc on full throttle starts, so over 2500w. Motor is cooler than before and now the esc is starting to get barely warm. New problem is I keep jumping teeth due to the extra power even with the chains on very tight.

So now the 1" axle #35 drive line upgrade is happening sooner than later and my cart is no longer complete. For the front I'll be welding on 5/8" spindle bolts and I ordered some hubs for the front and rear. I already have some 6" and 11" wide racing slicks that I ordered for the manco that will be great for street running.

Another mod will be to raise and change the steering wheel. I'm thinking of using something similar to a bicycle handle bars.

 

[Bmr4Karts]

Finally had time to work on the dune buggy. The rear end upgrade is complete. Up next is adding large spindle bolts up front so I can have the same size tires all around.

Big tires with #35 chain and no Jack shaft ride so much better.

 

[Bmr4Karts]

Got the front spindles all done. Was a lot easier than I thought it was going to be. My $100 HF welder was the best purchase of 2019. Now I'm just waiting on a inner tube and some 5/8 fine thread nuts for the front spindles. There's one small nylon spacer offsetting the front tires to prevent rubbing at full lock.

Next mod which is completely optional is raising the steering wheel and switching it to a bicycle type handle bar.

 

[Bmr4Karts]

95% done. Does about 30mph with 10t 67t gearing. I may raise the ratio to get more bottom end.

https://youtu.be/4yciedD1-Ak

 

[Bmr4Karts]

Today I change the steering to dual tie rods instead of a single tierod with a pitman arm. The steering is very sensitive around center, I probably need some toe in or something.

Hit 32mph on a slight downhill according to my GPS app.

 

[Bmr4Karts]

Never ending story. So I have learned that the front steering has bronze flange bushings. I learned this after I cracked and lost one while bashing in the backyard. A 7/16 bolt fits perfect on the stock rod and I drilled out the spindles for it to fit. A couple washers are needed to fill in the gap.

 

[HoldMyBeer]

BMR,

i have an youth size gokart that im converting to electric with a PowerWheels F-150 Body. i have seen a couple Razor Electric Drift GoKarts for sale on craigslist and offerup etc. if i pulled the electronics off of one and used it on the youth kart and upgrade to 48v, would it be worth it? the Razor is $50 and im not made of money. the weight of driver is about 60lbs i guess. also what is the chain size for those Razors?

Brian

 

[Bmr4Karts]

You can't use the razor electronics with 48v (or at least not for long, they are meant for 24v) so there's no benefit to buying one just for it's electrical components. Also, the stock electronics are ridiculously weak, 250w motor and like a 13 amp controller. Cost wise the best option is to buy a my1020 brushless motor with controller ($120 to $140) and use a 3 speed switch and gearing to limit the top speed. Any brushed motor and controller setup strong enough for your youth sized kart will cost just as much.

Razors use 25H chain.

 

[HoldMyBeer]

Thanks! I'm glad I asked you before buying. Btw cool build!

 

[Finotron]

BMR, your build is amazing. I would love to figure out how to put bigger tires on my son's Due Buggy. What FB group did you join to get mod ideas? thanks

 

[Bmr4Karts]

BMR, your build is amazing. I would love to figure out how to put bigger tires on my son's Due Buggy. What FB group did you join to get mod ideas? thanks

Mostly was "Powerwheels racers for Adults". They build custom frames and put Powerwheel toy bodies on top of them. Most of their race karts use the Chinese 48v brushless setup and go 20mph but they turn very well.