B&S 5HP modifications and questions

[Mr.Green]

B&S 5HP modifications and questions with Pictures

Hi newbie here. I just got an old worn out minibike and of course I cant leave it alone. I tore it apart, painted it, cleaned and rebuilt the carb, removed the governor, pulled the head, going to grind down the eye brows and grind down the slag in the intake and exhaust ports, removed the exhaust with the intent of making a header.

Here are the motor specs.

5HP Briggs and Stratton
Model# 132232
Type 4036 01
Code 30092827

Questions:
1: How should I do the throttle linkage?
2: Will I need to rejet the carb? If so, how do I get the jet out? I couldnt figure it out..
3: Do I need to worry about the steel flywheel breaking apart?
4: Do I need a tach?
5: How should I do the header / straight exhaust?

I am sure the answers are on this board somewhere, I just figured I would ask. I havent counted the teeth on the gears yet.

Looking forward to riding this thing. Well its for the kids anyway. :rolleyes3:

Thanks for any help!!

 

[Mr.Green]

Nothing huh? :krickets:

 

[r_chez_08]

Welcome
If you could post some pics we can help you with the throttle.
Same for the carb rejet.

As for flywheel explosions, what rpm are you planning on?
Everybody has their own opinions about what rpm billet is required and if it is really required at all.
Personally I do not want to die at 15, so I would say 6.5k tops with the stock flywheel. If you dont know the history of the engine, probably 6k.
However I would replace the connecting rod over 5.5k, or if you were to change out valvesprings.

You do not require a tach, but it is useful if you wish to know your engine limits etc. It is not essential.

The header wants to be at least 18" (I am a hypocrite- mine is about 12")
If you have a flange exhaust mounting system you need to make a flange or cut one of an old exhaust. Then use pipe with an internal diameter just over the internal diameter of the port.
You can attach/ make mufflers etc if you want.

If your exhaust has a screw type port then just buy some pipe with threads the correct size and thread it in!

 

[Bluethunder3320]

pushing an engine past the governed RPM will reduce its life span and of course wear out internals faster.

if you want to be 100% safe, dump $160-180 in for a billet rod and flywheel. however, i feel that with a STOCK valve train, you will be fine, because the valves will float before engine destruction happens.

not saying that it WONT blow up if you hold it wide open with no load for a long time...

the governor allows more throttle on demand when needed to reach 3600rpm, and once it gets there, it keeps the throttle constant. when more load gets applied, more throttle is added to compensate the drop in rpm.

removing the governor will let you keep it wide open all the time when your foot is floored, and the engine will not slow itself down once it reaches 3600. it will continue to gain speed until the valves float at around 5,500rpm.

a tach is just getting fancy on a go kart, IMO.

try your current setup before rejetting. it might be fine.

simplest way to make a straight pipe is to buy a threaded pipe and just screw it into the exhaust port, get this at a hardware store...

flywheel explosion is a myth but will happen at some RPM. (is this 6k, or 15k?) no one knows.

if you are removing governor as i assume. wire the throttle directly to the carb butterfly. all setups are different. search the web for some (and this forum).

welcome to the forums and good luck!

 

[Mr.Green]

Here are some pics. This is for a mini bike.

 

[Mr.Green]

What about running the engine shrouding? Will I get better cooling with or with out them? Will the fly wheel fan and engine shrouding cool better than no shrouds (exposed fins) running down the road at speed? I have lots more questions.

 

[jeremybentham]

Keep the fins on. They are what cools your motor. They're there for a reason. They keep the air generated by the flywheel in close proximity to the motor for cooling purposes.

As for your carb, you've got yourself a 'fixed-jet' carb. It takes A LOT of work, tiny drill bits, and patience to get any more out of them. Do-able, but not worth it, IMO.

Get yourself a 'flip' type choke carb or failing that, a slide choke carb and go to town. Ream it out a hair, make the bore and all the angles and ledges and so forth as smooth as possible.

 

[Mr.Green]

Where to get a better carb? Search or does someone sell aftermarket ones? I think I might just try and make a throttle linkage for this one for now. Not sure.

 

[Enduro Karter]

If you need one of the older pull style choke carbs, I have several that I could sell you for cheap. Also, if you need other performance parts for this engine, I still have a whole box of Briggs parts from when I ran the Flatheads on a dirt kart years ago. Think I have like 5 or 6 carbs, and about 20 camshafts.

 

[Mr.Green]

If you need one of the older pull style choke carbs, I have several that I could sell you for cheap. Also, if you need other performance parts for this engine, I still have a whole box of Briggs parts from when I ran the Flatheads on a dirt kart years ago. Think I have like 5 or 6 carbs, and about 20 camshafts.

Sounds good. I will shoot you a PM.