4 stroke basics? (A 206 Primer)

Our track is mostly a 2 stroke track so I have little information on 4 strokes. Can someone educate me on the differences between the common Brigg’s engines available for karting? What if any tuning is done on these engines? How long does a 4 stroke last before needing work? I understand there is a factory “seal” on these motors what happens when the case needs to be split?

Thanks for the input

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so the most common cheapest and most competitive engine made by briggs is the lo206
i wuld recoment getting it tuned by a professional if its in the buget but its not required we normally do 40 hours between rebuild

Bob. To my knowledge lo prepped is about 800 dollars. There are no rebuilds per se but from what I’ve read oil change after each race weekend. My understanding is when they get older you just go buy a new one since they are pretty cheap. But, I have not driven mine much so I’m not very wise.

When they have been rebuilt are they still legal for racing in the same class?

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206 “Rebuild” = head and carb. We call them “refreshes”. Yes, they are still legal afterwards.

If you have an issue with the short block, it can be replaced. They are about $300 MSRP (~$500 parts and labor through us).

We go about 10 hours before top end refreshes (~$175 parts and labor) and 2-3 seasons before even thinking about a short block.

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ya that’s pretty much what everyone does

So what is the difference between:

World Formula

I think wf or animal is more like 15hp.

Also, the dirt fellas take the non sealed engines and tired LOs and make em into 30 HP monsters.

Animal is the “base” product from Briggs Racing, derived from the Intek line from Briggs and Stratton. 206cc OHV engine. It’s kind of an umbrella for the karting product. It can be anything from a Briggs 206 to something making 20HP on methanol.

Briggs 206 is a sealed at the factory, stock Animal. 8HP. 6200RPM limiter. Spec series with a controlled rule set. By far the most common engine raced right now in the US on pavement. Well over 3000.

World formula started as a CIK four stroke class in Europe, but really only Briggs made an engine for it for a period of time. It’s based on the Animal/Intek with quite a few changes. Cam, carb, 7100RPM limiter. Non sealed, 15HP, rules are more liberal on modifications. Not very common these days. It sees good showings on east coast (Boston/NH area), a little in MN and (possibly) Arizona. I’d say less than 200 being raced nationwide right now.


Thank you for the information James.

I’m still at a loss on the difference, if any, between LO206 and Animal. A nearby track lists both classes. However, there are some differences in tires, weight and fuel. Would it be the same motor for both classes?

You mention a stock 206 is about 8hp, what would a “blueprinted” version such as Comet be?

Only the track can answer this really. It’s an ambiguous term that cover many variants.

“Blueprinted” would also be 8hp. You’ll see stories vary all over the place from folks saying they had great performances out of the box and others saying they insist on running “blueprinted” engines. At the least, it’s gone over to ensure the floats are at the correct height, carb is properly aligned with the flange, valve lash checked, etc etc. A lot of it is piece of mind and there’s nothing wrong with having that!

It’s stock from the perspective that it’s built to the “stock” parts list and specs Animal\Intek by Briggs. The 206 is a stock Animal, sealed by Briggs.

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What track? Maybe someone knows the track and can help.

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I will inquire with the track. I was trying to understand the nuances first.

where are you based from i can check out if i know any tracks near you?

So some more noob questions:

I see there are several options for clutches as far as brands (any differences?) as well as inboard and outboard (I assume this is where the sprocket is, why would you choose one over another?)

ON a LO206 what can or needs to be done. I have read setting the valves which I assume is like a pushrod V8 (valve lash) and the float height set on the carb (is there a tool for this?) Anything else that needs to be done or is done in the process of making a box stock motor track ready?

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I’ll do my best to answer.

First clutches: There are many options, but most folks run either the Premier Stinger or the Hilliard Flame. You can find internet discussions and FB threads in the 100’s of comments around which is better. I think at this point, I would just say it is personal preference. We use the Flame for its simplicity. It seems to be the most popular (maybe 60-ish % of the market). Inboard vs outboard has to do with the which way you mount your clutch. Inboard has the drive gear against the engine. Outboard has the drive gear furthest out on the crank. You pick which one allows the best clearance for your engine/mount/chassis/chain/gear combination. Again, there are arguments all over the internet about which one is better (outboard gives more clearance vs inboard causes less stress on crank). I have run both with success.

Now, for the fun stuff. The 206:

A 206 in a box will need quite a bit of assembly. Theoretically, it is as simple as exhaust and fuel lines and let her rip. Set the float height, set the lash and you are optimized, right? There are some more nuances to it. This is why folks pay “builders” to do the work. Let me give you an example. Do you know how far on to put the muffler onto the pipe to give you the most power? Do you know what coil gap or ignition timing gives you the most power? Or do either one of those really even matter?

You will get a ton of answers. Many people will say: I took it out of the box and won with it (and i have seen this done). Many people will say “You have to run this guy’s $1400 engine and its worth 10% more power” (and i have seen these people win, as well).

I try to give newbies this answer. How much do you want to learn and how much peace of mind do you want? Do you want to learn some DIY stuff and just hone your racecraft? Buy one in a box and tune it yourself. Do you want the peace of mind knowing your stuff is as good as anyone elses and jsut want to pull the string and go? Then find a “builder” you trust and support them.

Even though I sell race ready and dyno tuned 206s, I think you can have “success” (this is different to different people) either way.


You make some good points. I am noticing that engines are not being stocked but have to be ordered and there is a leed time. whats going on with that?

I ran kt100 for a few seasons and the clutch was a weak spot. Now running KA100 we almost don’t even think about the clutch as there is nothing to adjust and they are very reliable. Where does the 206 clutches fall on that spectrum?

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Clutches are IMHO way more work then even KT on some tracks and complete afterthoughts on others…

206 clutches are very set it and forget it. Get clutch, put your choice of springs in it (if different than what comes with it), and clean it every once in a while.

Engine supply: Crayola Virus has cause supply issues I’m every industry, karting is no exception.

Yeah, I had to wait a month an a half for my engine to get here. They are in short supply, and high demand right now. Manufacturers in ALL industries are still coming up to speed after Covid shutdowns.