Typically what is the maintenance with l0206? When they need a rebuild, can the be re-sealed and updated, similar to a Rotax motor? Whats the cost for a rebuild?
Change the oil, check the carb float every few races, and clean the air filter. If the bottom end is worn out you can build a Animal or remove the head and install it on a new sealed short block from Briggs and run the Lo206 class.
The bottom end can not be resealed, but that shouldn't be a concern. I would bet that my Sons 206 had close to 2k laps on it before I had new springs put in it at the end of this year. He races at Road America and Shawano, so it gets a decent workout. I use Briggs Amsoil and change it out every 3 races. Like mentioned above, keep the filter and carb clean and you will be fine for a long time. If you are looking for an answer in hours its many, many, more than a lot!
The best "when it needs maintance" tool so far has been the LEAKDOWN tester. We are now going on the 3rd year of road racing on the LO206 and she is faster than ever. Leakdown is staying at 3% when it starts to go up check the valve sealing and relap. SOME oils seal up the rings better than others (;-) Meow.

On springs run it untill you start getting the Flutter below 6050 rpm that is the Rev limiter setting. IF you see flutter blow that then time to change the spring or springs that are floating.

Just a thought, or 2 (;-)TP
You may freshen, or change parts in/on the head, and carb at your discretion. This assumes the replacement of any parts, with equally legal, stock parts.
The SHORT block, cannot be entered or altered in any way.
The SHORT block is sealed. The head and carb are not.

The short block cannot be rebuilt or opened up and then re-sealed or returned for legal stock LO206 use.
In the highly unlikely event that the short block NEEDs work, it must be replaced by another, factory sealed short block. ($300.)
Keep oil in it, and the short block will last several seasons.
On the few that we've had come in for rebuilds, you're looking around $45 for parts AND labor -- total out the door price. That includes a new head gasket, spark plug, and valve springs. Cut/lap the valves and seats, thorough cleaning of everything while it is apart, and reset the carb. Valve spring life depends alot on your maintenance. Be sure to roll the engine over to top dead center after you shut the engine off (to let the springs cool at their most relaxed state.)

I have to agree with Terry (VMax) and others -- these engine get better and better the more they loosen up. Keep clean oil and air filters on them, and they last and last.

What's not to like about the LO206?!

Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
At this point the only thing that I do not like about Lo206 is that nobody else is currently running it at the track and the track decided to get rid of clone. So far nobody supports L0206 at the track currently (it may or may not change) So my choice is to take a risk with the l0206 or run Kt100 Pipe, which should have a decent amount of drivers. I think what would most help build up 206 would to have a exchange program for clones.
What does a KT 100 with a pipe and everything else cost?
What does a LO 206 package cost? Go here: http://www.fastermotors.net/LO206ENGINEPACKAGES.html
What does it cost to refresh a KT 100 and how often does it need to be done?
What does it cost to refresh a LO 206? See above
How often does a KT100 break?
How often does a LO206 break. Haven't seen one yet. That's 5 years or more for me.
If you are comfortable with the KT100 package and the class is strong go for that. Maybe at a later stage get an LO206 to try and build a class at your track. Sure the 206 will be cheaper to run, but thats irrelevant if there's no sign of others taking it up at your track.
No kart shop in the USA has a larger or more diverse inventory of KT100 parts than the shop I work at. I sell parts and make sure our in house builder has what he needs to have quick turn around on the plethora of Yamahas that go out our door.

That being said, the LO-206 is the absolute best value in karting at the moment.

It sometimes takes people a while to see the light, but eventually a good concept catches on.

If commons sense dictated our actions, the nasty habit of smoking and tobacco use would disappear, cancer rates would drop, and the world would be a better place ;)

The only thing I see that noboby noted was keep an extra float kit and a inlet needle or two along with a few spare bowl gaskets. The every day pump gases being sold are getting nastier all the time, and these three items are really the only high rate consumables we see lately.
Yea but they sound terrible and smoke a lot.
A TV add comes to mind about motorcycle insurance and a guy with a weed eater.
Yamaha Average Numbers

Complete Bolt On SuperCan Package $2211.70
Complete Rebuild with Break In and Dyno $607.00
Top End Rebuild (no break in or dyno) $267.00
Clutch Rebuild $195.00

Comparable LO-206 Kit with mount, chain, and sprocket (everything to drop on un-accessorized kart) $873.80

Fourteen Race season, a Yamaha Can engine should see a rebuild around race #7
The engine should be completely rebuilt during off season.
Typical Dry Clutch (I used two disk L&T as example) should be rebult about midway through a typical 14 race season.

A properly maintained KT-100 will have the exact same possibility of breakage as an LO-206 or any other properly maintained racing engine.

A KT100, just like an LO-206, requires the owner to use good quality fuel and oil, and maintain the incoming air through a proper air filter maintainance regimine.

If you drove a 100cc air cooled rotary direct drive with a Vevey pipe, you would never want to drive anything else ;)

But those days are gone. I, like the rest of the few with 30 plus years of karting background, are relegated to running whatever classes the local tracks put into their daily program.

My sons JR LO-206 has been the easiest engine to operate in my entire life. I can't wait to pop a 6100 rpm coil on it, change the slide, and race it myself next season.
I think what we're seeing is the "cheap" buy-in price of used Yamis and flatheads right now. Oval 2 cycle racing all but died 10+ years ago, yet now it's seeing a "bit" of a recovery as the engines are being sold "dirt cheap", for a couple hundred dollars used (ebay, craigslist, etc.) While these engines might run, they certainly aren't top of the line like a new one that Kent or any other builder would produce. I'm selling more fresh/used flatheads today than anything else we offer. Most are two disgruntled clone racers who are coming back to the flatheads to avoid the constant rules changes, updates, etc that they see going on with the clones right now. I see the 2 cycle resurrgence (if it really is that) kind of like the clone deal started out -- great introductory price that brought some older karts out of dry storage, then it got pricey real quick. All it takes is one guy in the class with deeper pockets than the rest, and he'll have a pro-built engine (no matter what class) that will outperform his competitors.

Ol Jimbo and I have been preaching the benefits of the LO206 for several years now. While it has taken a bit of a foothold at a few tracks, it's not been as widely embraced as we hoped or expected. What we've seen from sales is scattered (sporadically) across the country...then you get the problem of getting 3 or 4 of these guys together at the same track. While we field calls, emails, etc daily with questions about the LO206, performance, durability, pricing, etc, there's obviously a lot of interest -- but the hesitation comes in with, "I don't see a class listed for this engine at our local track", or "Will there be enough to make a class?" All I can say is to be bold! Be the first to bring an LO206 to your local track. As others see what this engine platform offers, it will grow. If everyone stays on the fence and watches, it'll never grow. Everyone that has run these engines, loves them. As you consider freshening/updating your clone (Yami, flathead, any other engine) this winter, consider the cost to change over to the LO206. Add up the benefits, maintenance, rules changes, etc and come to an honest conclusion about which engine package makes more sense.
Glad to hear you're on board with the 206 package, Mike -- keep in mind this is coming from one of the top 2cycle shops in the country folks.
Like, Mike, we ran the JrLO206 engine over 2 years on our kid kart -- I'm an engine builder as well, and I absolutely LOVE that I can just pull the rope each week and let my driver concentrate on wheeling the kart. We change oil once per race day, and checked the valve lash once during those 2 years of running. Didn't cost us a dime for rebuilds, etc over those 2 years. Now we've got an engine that he can grow with (unlike the Comer 50). Upgrade to the 6100 coil and install a long slide for jr class racing, or build it up as a blueprinted purple plate animal. This engine is as strong now as ever. What's not to like about that?

Definitely keep a spare inlet needle and fuel pump -- that's about the only problems I have seen on any of the 206's we've sold and seen at the track. :)