B&S I/C Flatty

[Rat]

I'd appreciate any info and specs... the most I can come up with is it was originally attached to a water pump of some kind (warning decal on the side of the shroud) and after measuring the bore and stroke its a 198cc.

I've cleaned it up and out. Fuel tank is a total loss because it was half full of water but after cleaning the rust out it was Swiss cheese... so full of pinholes and soft on the bottom.

I gutted all the Gov'nor crap, plugged the case, and cleared the ports of their atrocious casting flaws (nearly doubled the valve pot sizes by just smoothing and removing ridges) this thing should really scream when I get it back to the kart I peeled it off of.

I do not know:
The output power rating
Age (if the method is true its a 1987)

I DO KNOW that nearly all it's parts are still very available but also very expensive.

MODEL TYPE CODE
132232 0324-01 87051107

 

[Denny]

Probably going to buy a gas tank and carb. I think there is a site with all the Briggs info on it. But don’t remember where.

 

[karl]

13ci, 5hp. Dual ball bearing crank. Manufactured May 11, 1987

Replacement fuel tank #694315 , List price $143.80 so Id look for a used tank or donor.

 

[Rat]

13ci, 5hp. Dual ball bearing crank. Manufactured May 11, 1987

Replacement fuel tank #694315 , List price $143.80 so Id look for a used tank or donor.

Good to info, I'm not interested in keeping it original though.
I don't like how close the intake is to the muffler or the muffler was to the top of the tank.

I intend to put a straight pipe on it.

 

[Denny]

Karl is a B&S god! He can and will answer all your questions!

 

[Rat]

Karl is a B&S god! He can and will answer all your questions!

Have to tag him in I guess.

I'm not particularly looking at making it a power house with hop up parts, just make it run better and stronger than stock and either sell it or maybe slap it back on the disgusting little Kart in was on after a bit of work on it and sell the whole shebang.

It's definitely a store bought thing for 4' to 5'6" riders (kids) possibly antique.

 

[karl]

Are you looking for an off the shelf solution, or do you want to fabricate?

 

[Rat]

Are you looking for an off the shelf solution, or do you want to fabricate?

Depends on the fabrication complexity and cost.

I am severely and painfully reactive to fiberglass and avoid that stuff in any form at all cost possible.

I do have a half decent wire feed that can be retrofit as a full on mig, but that's an additional material cost I'd much rather avoid for now.

Ultimately I'm open to any and all suggestions, and intend to probably go for the one that falls in line with being both cost effective, and reasobly within my skillset.
I will say that my skills and knowledge are a very broad range and always expanding because I'm not too chicken$hit to make mistakes and learn the hard way even though I prefer to learn from the mistakes of others and take calculated risks to avoid them.

 

[karl]

cleared the ports of their atrocious casting flaws (nearly doubled the valve pot sizes by just smoothing

Hope you did not enlarge the exhaust port or remove the threads, the exhaust port is already way oversized.
Kart racers fill in the threads to reduce the size of the port ( sometimes filled with grease that hardens)

Also the bump on the right side of the intake port is important to keep.

Anyway Ive never heard of a fiberglass intake manifold.

Here is a great off the shelf solution

https://www.eccarburetors.com/vm20-slide-flathead-gas-carburetor-kit

Ill throw in two examples I made from scrap steel I had in the garage,
one a small block honda clone carb (not meant for performance), other gx390 carb

 

[Rat]

Hope you did not enlarge the exhaust port or remove the threads, the exhaust port is already way oversized.
Kart racers fill in the threads to reduce the size of the port ( sometimes filled with grease that hardens)

I did not, I had planed to use a 12" section of threaded black iron pipe for an exhaust header at least.

Also the bump on the right side of the intake port is important to keep.

Not sure about that, probably gone. There was so much casting flash and sharp edges that I smoothed it all out for maximum velocity... I did notice a flattish section down the right (outer edge farthest from exhaust port) of the intake and mostly just blended what I did into that.

I did not do anything to either port at the manifold faces, just cleared the trash from where the seats meet the ports leading to the manifolds.

Anyway Ive never heard of a fiberglass intake manifold.

In all fairness you weren't exactly specific what you were saying to fabricate... what was left of the OE stock tank went to the dump with the trash today, but having the top seat where the carb mounts I could totally make a fiberglass fuel tank if I wanted to suffer the consequences of that choice for the next month or two as well as burn any clothing worn during the process.

Ill throw in two examples I made from scrap steel I had in the garage,
one a small block honda clone carb (not meant for performance), other gx390 carb

I made the manifold for my 208 to put the PWK 24 on it so I'm aware of the various carb mounting options, and just need to check the stud spacing before I decide anything too much

 

[karl]

top seat where the carb mounts I could totally make a fiberglass fuel tank if I wanted to suffer the consequences of that choice for the next month or two as well as burn any clothing worn during the process.

lol a fiberglass fuel tank sounds like a terrible idea. No idea why that was brought up.

You said you did not like the factory carb/ tank setup, so I provided other options.

Bigger carb is not always better. If you are serious about these engines, id recommend this book

Go Kart Racing Engine Builders Book Guide for Briggs and Stratton 5 hp Flathead 5800077009709 | eBay

Find many great new & used options and get the best deals for Go Kart Racing Engine Builders Book Guide for Briggs and Stratton 5 hp Flathead at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Rat]

lol a fiberglass fuel tank sounds like a terrible idea. No idea why that was brought up.

You said you did not like the factory carb/ tank setup, so I provided other options.

Bigger carb is not always better. If you are serious about these engines, id recommend this book

Go Kart Racing Engine Builders Book Guide for Briggs and Stratton 5 hp Flathead 5800077009709 | eBay

Find many great new & used options and get the best deals for Go Kart Racing Engine Builders Book Guide for Briggs and Stratton 5 hp Flathead at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Definitely had no intention of putting a massive carb on it, maybe a PZ19 at most a PZ20 (the carb you are most likely to find on a CRF70 or any one of a fistful of CRF50/70/90 clones

 

[karl]

Definitely had no intention of putting a massive carb on it, maybe a PZ19 at most a PZ20 (the carb you are most likely to find on a CRF70 or any one of a fistful of CRF50/70/90 clones

That will do! Thats why id recommended the 20mm mikuni, not larger.

 

[Rat]

That will do! Thats why id recommended the 20mm mikuni, not larger.

I happen to have a PZ19 on hand from a CRF70 clone (Baja Motorsports DR70) I worked on. It was more efficient to replace the carb with a PZ20 and clean the 19 later as a junk take off left behind by the machines owner

 

[Rat]

That will do! Thats why id recommended the 20mm mikuni, not larger.

What do we think of sidedraft?

Usually that tipped angle isn't an issue, but I should drop the bowl and double check where the float hinge is.

 

[karl]

That should the trick.

Just check the oil level for a bit, if the carb leaks the fuel will run down the valve guide and flood the crankcase.
An inline shutoff valve is cheap insurance.

 

[Rat]

That should the trick.

Just check the oil level for a bit, if the carb leaks the fuel will run down the valve guide and flood the crankcase.
An inline shutoff valve is cheap insurance.

Yeah I'm definitely planning an inline shut off, stock Hemi 212 tank doesn't have one because it's on the carb body instead. The carb has been cleaned out and tested so I'm not worried about any leaks with it specifically.

I'm actually a bit more worried about pinhole vacuum leaks in the flange welds, I double pass welded so I'm probably fine there. Like I said I gotta double check the float hinge position, but the faint tilt should be fine

 

[karl]

Yep the angle should be just fine. I just take a flashlight and shine it on the inside of the welds, and make sure no
light escapes, tac it up as necessary. Any pinhole that won't let light through is no concern, a layer of paint will
take care of it

 

[Rat]

Yep the angle should be just fine. I just take a flashlight and shine it on the inside of the welds, and make sure no
light escapes, tac it up as necessary. Any pinhole that won't let light through is no concern, a layer of paint will
take care of it

It's chromed so no paint lol

 

[Rat]

Yep the angle should be just fine. I just take a flashlight and shine it on the inside of the welds, and make sure no
light escapes, tac it up as necessary. Any pinhole that won't let light through is no concern, a layer of paint will
take care of it

I put the stock fart can back on for now so really all that's left is sealing the crankcase cover, slop some oil in it, rig up a temporary hanging fuel supply and yank on it's cord to see what happens.

The clutch is pretty beat up but seems functional enough despite bell cover circlip is busted and I need a shaft end bolt that actually fits the threads. Any idea what size and pitch by chance?