My sweet B&S resto project

[JTSpeedDemon]

My Sweet Briggs Flathead Restomod

I am a 13 year old that recently acquired this VERY old single wheel drive go kart for $60 off Craigslist. I'm pretty sure the last owner said that this is not the first engine, but it is powered by a 13 ci (208 cc) 5 HP Briggs and Stratton flathead built on Dec. 13th, 1985(same year as Back to the Future!). It has an updraft carburetor with manual choke, aluminum block, head, and cooling fins, drum clutch(12 teeth, and 66 teeth on the axle, #35 pitch chain), and a side mounted recoil starter. The seat back needs to be replaced or fixed, and the is no seat bottom. Another drag is that it's got some minor surface rust, but I'm planning on treating it. It's drive wheel bearing is bad and lets the chain slide back and forth and "lock up" in the words of the last owner. It has an different gas tank from standard that is gravity fed. Front wheels are tube 4.10/3.50 pattern with 5 inch rims. Rears are tubeless 13x5 with a six inch rim. Rear wheel bearings are 3/4" ID and 1 1/8" OD. Front wheel bearings are 5/8" ID and 1 3/8" OD.
I have a slight inkling that the frame is based off an Azusa frame of some sort, as Azusa nylon wheels could replace the current steel ones, as well as the fact that I'm pretty sure a certain type of Azusa pedals can replace the current custom ones.
But then again, from the looks of it, this frame is probably nothing like what it was originally.


My plans for it:

• Beef up the internals(piston, con rod, maybe crankshaft)
• Put a real leather seat on
• Turbo- or supercharge it
• Maybe put on a modern sidedraft carburetor
• Put some Back to the Future Time Machine bodywork on it
• Blow everyone away!
• Put double front disc brakes on
• Tach and speedo
• Little pseudo AC system
• Get rid of the steering play
• Rustproof the frame
• Possibly a small motorbike-like transmission?

 

[tgus3]

big plans, big plans. Hope you have good luck with most of that but its gonna take a whole lot of time and money to try to turbo it. good luck anyway

 

[J.S.@SMS]

The best thing to do, if you're going to boost it, is to build a box around the carburetor that seals between the carburetor and manifold. The compressed air will pressurize the air inside the box and the carburetor, instead of just the air in the carburetor. This is necessary with a carbureted system, because without this pressurized air would enter the carburetor and force the gas down the jet and then force it out of the bowl around the float seal. This however is not necessary with a fuel injection system since the injectors are responsible for fuel delivery and there is no float bowl.

 

[JTSpeedDemon]

If turbo is too complicated, I would imagine that supercharging would be simpler and better, as there would be no turbo lag, and I could just stick a pulley/belt or sprocket/chain between the end of the crankshaft and the supercharger.

 

[itsid]

for the price of such supercharger
(making me think of vintage VW smog pumps and alike root pumps from japanese micro cars)

you can buy a used 100 horse motorcycle engine easily...
I know, less cool factor and more life threat...
but just to get a feel for what such an additional horse costs on average

And frankly calculating the size and ratio is also not exactly easy.

since the rotational volume of the pump might in fact change over the engine's rpm band..
(there are no wall seals.. they must leak a bit in order to work reliably.. the slower they turn the more they leak)

And with that we enter the realms of fluid dynamics..
eyeballing it and adjusting it in order to fix issues is the only homebrew way I think is feasible
(short of paying thousand+ bucks for a good simulator software)

So IMHO: a supercharger isn't easier or simpler to get working well than a turbo charger is.
In fact I think the turbo is a bit easier to 'adjust' since it relies on the same fluid dynamics
(exhaust flow) on the driven side

But please try... I'd love to see that being done..
I'd looove to get my hands on a VW smog pump myself but that's a totally different story

'sid

 

[JTSpeedDemon]

Yeah, I understand that it would be a Herculean task as there are no superchargers designed for 13 ci engines(LOL), but not only would it be fun and good learning, but just being able to say 'My go kart is supercharged!' is awesome. By the way, anyone know the compression ratio of this engine?

 

[itsid]

Well it HAS been done (or say tried.. can't seem to find any example currently)

with above mentioned smog pump or the Aisin AMR300 (a similar sized charger off some 600cc japanese micro car)

root blowers are nice since they have a fairly small "volume"
they need to spin quickly in order to compensate for leakage anyways and thus need to be geared accordingly anyways.

So such small blowers will work well for a whole range of engines.

OH btw you are incorrect.. there were superchargers for almost any size engine
starting from as little as 10cc (cc NOT cui!!) (some bugatti motorcycle [powered bicycle rather] from the fourties had such)
and everything up to modern day 6000+cc engines
and that does include 212cc (roughly 13cui) of course

And while I do not know any for exactly such size..
I know the above mentioned root blowers worked on 150cc gy6es and of course the 660cc japanese car they came from..
sooo I'm fairly certain the 212cc are not much of an issue size wise.

(it's the gearing you need to worry about!)

'sid

PS most recent was the original Peugeot Jetforce scooter (125cc came with a supercharger and fuel injection from the factory! )

 

[JTSpeedDemon]

Hmm, excellent point about the supercharged Bugatti assist bike. Obviously I am going to worry about getting the engine working properly before I start hopping it up, but it's nice to have y'all here to answer my questions. By root blowers, do you mean a Rootes type supercharger?

 

[JTSpeedDemon]

AARGH!! Ever wanna either rewind time or simply bash your head against the wall for making a stupid mistake that was easily avoided? That's how I feel right now. Wanna know why? So, I changed the oil in my engine, and by default, my dad teaches me to put Mobil 1 5W-30 Synthetic in engines by default, so, I put that in the engine. Then, a few days later, I looked in the Haynes Techbook for small engines up the 5 HP, and it says to put in :"30-weight, 10W30 or 10W40/SC, SD, SE or SF".
Two questions:
Is there ANY chance that the Mobil 1 5W-30 Synthetic would work?
By 30-weight, would Castrol 30 work?

 

[itsid]

5w-30 full synth is perfectly fine!
overkill maybe but it'll certainly can stay where it is until the next oil change,
then you might want to get a higher viscosity or lower as you prefer.

And yes I meant roots type blowers (they're NOT superchargers!!)
they are positive displacement pumps (blowers)
and can be used as superchargers, but they're not originally

'sid

 

[JTSpeedDemon]

Ooh!ooh! Idea! I want to disable the governor, upgrade the internals(con rod, piston, maybe crank and cam, and definitely valve springs) and put on a billet aluminum flywheel! Rev it up!

 

[JTSpeedDemon]

YAY! Finally put in the welch plug on the carburetor! It's on the end of the carburetor "L", and I made sure to put Permatex No. 2 non hardening around it according to my Haynes manual.

 

[Texan]

Wow, you're 12...not many kids around like you. I don't remember when the last time I saw a kid wrenching away. Keep up the good work

 

[JTSpeedDemon]

Yeah, I'm also into amateur(ham) radio and it's the same situation with not very many kids, probably 'cause other kids just wanna play Call of Duty, and Halo, and other first person shooter games. Then they wonder why no one wants to hire them when they apply for a job. Part of the reason I'm so into karts is because I work on the family cars a lot with my dad. The cars I KNOW I've worked on are: a 1996 Toyota Camry, a 1995 Toyota Camry, a 2012 Kia Sedona minivan, and a 1981 Mercedes 240D diesel with 4-spd manual transmission. I just wish everyone could drive go karts instead of cars! There would be SO many benefits! For one, think of how easy being a mechanic would be! Also how cheap maintaining one would be! Now it's not necessarily a perfect system, but I can dream, can't I?

 

[JTSpeedDemon]

Quick update: Got to work sanding/filing the rust off and made decent progress, but haven't made an progress since then. Reason being that I somehow bruised my foot very badly in a way that seems like it's fractured, but the doctor says it's not. As such, he wants me to rest my foot, so I can't go out on the back porch and work on it.

P.S-I'm going to need new front tires, as the current ones are rotten and the wheels a bit rusty, so where would be the best place to get new 4.10x3.50-5 tires. Can be tubed or tubeless like my back ones. Would like new wheels so I don't have to reuse the old ones. Could probably make do.

 

[JTSpeedDemon]

Update: Assembled the air cleaner, put in the fuel filter, finally managed to get the chain off, thus also got the wheel with the bad bearing off, found out that it's a 12 tooth clutch and 66 tooth sprocket (expected 25 mph from the calculator), found out why it was so hard to try to put the starter together (a little plastic anchor thingy broke off the starter pulley, making it just about impossible to anchor the spring) and thus ordered a new starter pulley off Ebay. Things are going well!

P.S - I am working on a website and Youtube Channel under the name Kartssource, keep an eye out for when I publish the finished website and post the first video!

 

[JTSpeedDemon]

You might not know this, but I am an amateur radio operator. As such, I went to the Irving Hamfest 2019(an amateur radio convention/swapmeet). While I was there, I picked up this air blower for $2!
Yes, this is related to my go kart.
It is brushless, and draws 2.94 amps at 12 volts DC.
My plans:
I will build a box around the carburetor and connect this blower to it to make an ELECTRIC SUPERCHARGER(Although strictly speaking it's a blower).
I'd like to know if ANYONE has ever heard of that!
I plan to also have a system so I can switch from blown to naturally aspirated and vice versa.
I have two 12 volt, 9 amp hour batteries, so I hooked one up to the blower, and boy does that thing scream! It would make a wonderful chorus along with the sound of a Briggs with a header!

 

[JTSpeedDemon]

Update:
Got the frame painted today with flat black Krylon primer+paint after doing a little more sanding. Right around my first sanding session on the frame, I sanded the steering tie rods to a kind of spun aluminum look, so I'm leaving that 'cause I think it looks slick like chrome. The front part of the red gas tank bracket has been painted black, but not the bottom and back. I will post pics another time as it's dark now.
I need name ideas! Preferably starting with 'Black _____'
Maybe Black Briggs...

 

[itsid]

well adding an electric blower will COST you power.. and LOTS thereof!

you cannot build a positive pressure difference with that tiny motor,
quite the contrary you will create another bottleneck
(increase air drag and speed loss due to the air having to push the blades)
and thus lose power.

I know you don't care.. but do not dare to call it supercharger when it's doing the exact opposite

'sid

 

[Tpdingo]

Update:
Got the frame painted today with flat black Krylon primer+paint after doing a little more sanding. Right around my first sanding session on the frame, I sanded the steering tie rods to a kind of spun aluminum look, so I'm leaving that 'cause I think it looks slick like chrome. The front part of the red gas tank bracket has been painted black, but not the bottom and back. I will post pics another time as it's dark now.
I need name ideas! Preferably starting with 'Black _____'
Maybe Black Briggs...

Black Raven.

Make sure not to tell IBM or they're going to sue you .