Rebuilds. X30 is basically top end around 5-10 hrs run time. And 10 is too long.
TJ apparently ran a full season KA no rebuilds
I don’t really have hard numbers on it, but plugs and carb kits are fairly similar between the two engines. Every couple races for us maybe on the carb kit and a new plug to start the weekend, although some of that stuff could go longer and be fine.
Top end rebuilds are more often in the X30. We could do a whole national/regional season on a KA without doing a top-end. The X30 is maybe every 2 weekends at that level.
Of course these numbers can vary and some parts can go much longer if you’re doing club racing or regional racing and don’t push the engines quite as hard.
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Even as club guy… I can feel it after 3 race weekends. Power drops.
It’s a rooting tooting fun engine. But I am sorta jealous of my rotax competitors as it seems they have it easier on the maintenance front (in the $ sense).
I assume that there’s other aspects that make the trade off worth it to some.
Politics is politics. It’s really down to a lower-headcount in my region, combined with us having too many engine packages in TAG together as it is.
It’s a discussion for another thread, but we don’t do a good job getting new racers into the sport, and so all of our activities just canniablize against the ones that we already have.
I’d love to have 100cc class, so I had a less expensive two stroke to run regularly. Like someone said above, keeping the X30 maintained at it’s peak performance can be expensive, and since I run in a class against X125s, Rok GPs and PRD Galaxies, I need all of the poinies I could get.
I’d move to a KA100 in a heartbeat, if we could get out of own way up here. 
Trust me, as the KA engine package matures, fields grow and become more competitive, people with the budget will start rebuilding them more frequently. Then everyone will be saying KA’s need a top-end every 5 hrs when they get killed by a front-runner that puts in a new piston every other weekend. That’s just what happens as a base grows in any particular engine package.
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I suspect Christian is correct that as the class grows it will breed more people looking for an edge via a refresh. That said, there is still a real cost savings on tires. Almost every series is running the KA on one set of tires for the weekend. The other thing I like about KA is the racing(sorry for the tangent). The low HP and hard tires means draft, strategy and driver really matter. I love watching the KA races. The last 3 laps almost always decide the race. Don’t get me wrong, I love the X30 too, but I’ve come to find that it’s much more technical (setup and engine). Maybe the KA turns more technical too…but for now it’s not that way…and it’s lots of fun to watch racing. I guess I’m just a 100cc fan boy.
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Using SKUSA and RoK’s Vegas events as an example, think it’s pretty competitive as it stands such that we can make a reasonable judgement on rebuild intervals as they pertain to performance. Yes it’s relatively new, but by no means a complete unknown.
You can’t stop people spending money.
You can manage\reduce the impact that silly spending has.
But then you also can’t stop people making excuses either. Convincing themselves they have to own, rent, spend xxx because Johnny McPolesitter has.
So, from what I’ve seen from my experiences in KA, the motor is a rock solid package and I have no complaints yet after a year and a half of running it. We do a top end rebuild about every 8 hours but that’s more down to preference than necessity. The decision for me to do it at 8 hours was that I was only just as competitive as a driver that had a fresh rebuild at a race right before a major weekend, and I knew with a fresh motor I would be faster than him but even at 8 hours I was just as quick as he was.
I would say for a club driver you could probably do 15 hours without a top end. I did a full rebuild over the winter but I also ran the motor every weekend during the season with no problems.
The only mechanical issue I’ve had was a clutch going out after a race in the rain at my past weekend, but that’s more on us not checking it than anything, since the clutch lasted a whole season and a half before giving out. (Quick edit: just talked to my engine builder, apparently a bearing in the clutch blew out which subsequently cracked two shoes in the clutch as well. He said that’s the second time he’s ever seen a bearing go, which considering how many engines he’s built in the last 2.5 years since the KA was introduced I would say that’s just bad luck at this point.)
@DavinRS what happened here was one club guy got a KA100, and he let others drive it. Soon, everyone wanted a KA. Admittedly this was compared to a Yamaha and not a TaG, but if you get one and show people what it’s like they may follow, especially if you can show them cost difference between the two motors.
why not bring this up.
I lost 35 lbs last off-season to make myself competative in the local KT100 masters class. Worked out for me so pretty happy I put in the effort. Trying to figure out how much more I need to lose to race KA without a weight disadvantage.
Locally there won’t be a KA class other than Sr. and wanting to dip my toes in the KA water next year.
Does anyone know how much the battery / wiring harness and starter weigh on the KA? 5 lbs ? 8 lbs ? My understanding is that at least at the club level you don’t need those components installed and can run them utilizing an external starter correct?
Thanks in advance.
The KA package as a whole is pretty heavy. The engine is big, but you can remove some of the starter components to save some weight. I can’t remember the exact weights, but definitely heavier than a KT.
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TJ what does your otk ka kart weight without any extra lead? Trying to see where I would end up weight wise. Only thing I could find was the total engine package is around 44 pounds. So I’m guessing 170-175 pounds.
Not to speak for TJ but I asked a racer at the track last weekend the same question and his OTK KA100 kart was right at 180 he said with enough fuel to race.
That’s why I’m trying to find out how much without the battery and starter because with the fully loaded KA kart at 180 I have to lose another 15 lbs…10 sure would be easier. Currently at 195 lbs myself…I don’t think I’ve been 180 since like the 5th grade (Yes I was a portly young man)
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Thanks Andy, that is heavier than I thought it would be. I would be 370-375 as I sit. Already lost 20 pounds over the last 2 months to get below our 206 min weight. My goal is to drop another 8 to get down to 180. That would put me at 187 fully geared up and ready to roll. I need to find a lighter suit as the alpinestar I use is heavy.
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same…my OTK kart with a yamaha KT100 is like 162 with min race fuel so the KA is quite heavy in comparison when fully loaded with battery and starter.
I can’t remember what the kart is un-weighted, Chris is probably pretty close. Mine’s never had no weight on…
I know one of our guys is about 190-195 and he ran KA earlier in the year with no battery/starter/small fuel tank and he was about 7 pounds over. You could get a couple more pounds out of it if you went without a decal kit, but 7 over is pretty good.
Thanks TJ. If I could get to 5 or so pounds over I would be fine with that.
Just seeing this now. Usually I’d agree here – for example, the more big Briggs 206 events hosted around the country, the trickle down / ripple effect of that knowledge and extra tenths of HP end up at the clubs and the cost to be competitive goes up.
But I raced TJ in that season in KA. And when we went to New Castle, he ran down the leaders on his own on that engine at the end of one of the Finals. I did a top end rebuild halfway through the season and I honestly don’t think I needed to looking back.
With as similar as the VLR is, I’m sure the life and longevity will be the same. 100cc racing fueled karting for 30+ years with the Yamaha, and now with new technology of both a pretty rugged onboard starter and a hassle-free clutch, I can easily see it revitalizing the sport – it already has passed regional and local tag numbers from the 2010-2012 era in most places.
With me gear I’m about 215, and I on average come across scales around 385. So that makes my otk kart with ka about 170 lbs. I do have the ultra light battery, barley over a pound and minimum fuel. Also 3rd bearing removed.
Frankly i dont believe removing a decal kit is worth even a pound, now thats chasing hairs.
Go grab a full factory decal kit and weigh it, you’d be surprised. It’s been done for years for heavier drivers desperate to save weight. It’s a lot of thick material.