Why didn't Rotary ever catch on?

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Hey all. As many o you know I am new, again, to Karting. After a break of 7 years I am back and racing Rotax Sr.

The Rotary has always intrigued me, especially when there was the Rotary kart motor. It seemed so promising with its consistent powerband, low end torque, and low operating costs (almost no rebuilds!). So why didn't this ever catch on? Seems to me it would be a great TaG motor. Instead we keep going for these high reving, high maintenance kart motors which just makes the karting industry more and more expensive! Looking at it from the motorcycle world, karting has always been expensive!

I would appreciate any more experienced insight to this question.

Thanks all,
Justin

John Matthews · Posted: Sun Oct 28, 2012 1:25 pm Post subject:

The Aixro is a very cool motor but makes Rotax look cheap. Also, way too much power for all but the best drivers and they're mostly running shifters. The running costs might be lower but the rebuilds sure aren't and you don't want to know what happens when you break it Crying or Very sad

There are a few of them running competitively in UAS though.

Cheers,
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Heartbeat Power, LLC.

Brian G. Wilson · Posted: Sun Oct 28, 2012 2:22 pm Post subject:

I have to disagree with John as I run an Aixro rotary. Just out of curiousity, and this is a serious question as I honestly don't know, how much does a new Rotax cost? On the Rotax, I'm guessing if you bought the motor, carb and pipe as a package you are going to be in the $5K range? The Aixro comes complete with the motor, carb, pipe and motor mount for under $6,500.

I have put tons of hours on my Aixro without a single motor related issue. The carb comes from the factory set the way you need it, I have never changed jets no matter what kind of heat/humidity/cold I have run in. Between runs, I literally lube the chain as soon as I come in and refuel if necessary and just let it sit there until the next run. Last time I went to the track and they were running us 10 minutes on and then 10 minutes off while the rentals ran, my friend and I rotated 10 minute sessions from 9 AM until after 2 PM and never missed a 10 minute session. I would come in, he would lube the chain and top off the fuel while I cooled down and then he would suit up and go for the next session and vice versa all day......couple of guys made the comment they wish they could do that with their karts. Kart never skipped a beat and we were both beat at the end of the day. Read the manual and operate it as they dictate (within the rpm's, bearing & water temps they suggest) and you should have no problem.

As far as the rebuild go, they suggest every 100 hours to open it up and replace a few small items. My rebuild at 100 hours cost me less than $200, including labor. At 300 hours, they suggest putting in new main bearing, but the total with labor should still be less than $4-500.

I think if you ran a Rotax, shifter (take your choice of stock moto or ICC) and an Aixro side by side for a season or two, the Aixro would come out ahead as far as maintenance time or cost involved. There are a couple of guys that I know of that run them and we've all had the same experience.
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TJ Koyen · Joined: 03 Oct 2004 Posts: 1425

Leopard package, 3k. Aixro 6.5k. Maybe over time it evens out with maintenance costs, but it's hard to plop down that much cash for most people.

I'd love for them to be the class of choice, it seems like an awesome package. But so expensive initially.
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Brian G. Wilson · Posted: Sun Oct 28, 2012 3:29 pm Post subject:

I will say the Aixro is not the perfect, end all, be all package. At some smaller, tighter tracks, the Rotax is faster, then again, they're also faster than the shifters. They have a series that runs them in the UK and it is gaining popularity by leaps and bounds and they grid 10+ Aixro's each race and run MG Red's as the spec tire. The Aixro is also not good on long road courses with huge straights as it can't be held at WOT for more than 10-12 seconds at a time. Not a problem for me as I don't think I've ever had the occasion on any course less than 2 miles in length to hold it at WOT for more than 5-6 seconds before the next corner came up.

Ok, so the Leopard is $3k, is that the same as the Rotax? I keep hearing about this passport thing with the Rotax which sounds like you can't do the rebuilds yourself. Anyways, how many hours or seasons do you get out of a Leopard or Rotax before you buy a new engine? What is the resale value on them? How many total hours do you put on your engine a year, between track days, practice and racing?

Unfortunately, the Aixro is regarded as an illegal engine by the WKA. Therefore, any event that is sanctioned by the WKA won't allow you to run it and until that changes, they don't have much of a chance of becoming popular where the WKA is the dominant sanctioning body.
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Paul Makarucha · Posted: Sun Oct 28, 2012 4:25 pm Post subject:

Are the apex seals on the Aixro on the rotor itself?
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Brian G. Wilson · Posted: Sun Oct 28, 2012 4:42 pm Post subject:

Yes, I believe they are on the rotors, but I can't confirm that as I am not a mechanic and haven't personally opened mine up.
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Justin Martin · Joined: 27 Mar 2012 Posts: 328

Chris Hurst · Posted: Sun Oct 28, 2012 7:03 pm Post subject:

Can anyone explain to me how you can put apex seals on anything but the rotor itself? Never heard of that before.

Brian Degulis · Posted: Sun Oct 28, 2012 7:20 pm Post subject:

Justin I had the same question as you when I read about it. Then I drove one and for the life of me I don't see why they haven't taken off in the US. On most tracks they'll compete with a shifter. An icredible power band almost no specific power band at all. They claim 50 hours between rebuilds you would think it would be looked at as the answer. I came very close to buying one there just isn't anyone racing them in my area.

Brian

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Brian Degulis · Posted: Mon Oct 29, 2012 4:55 am Post subject:

A lot of it doesn't make sense to me. Rotax runs a while between rebulds but you can't do the work yourself. Box stock is now a chinese copy of a Honda that needs to be built before it's competitive. It should be a Honda GX200 with the governer removed bolted on to a kart but it's not. Kid karts run Comer's can anyone explain to me why a kart for the 5-7 year old range needs a $1000 2 stroke engine? Why not a simple cheap 4 stroke?

It seems like the governing bodies have paid more attention to the manufactures and dealers than the end user. It's much more complex and expensive than it needs to be.

Brian

John Matthews · Posted: Mon Oct 29, 2012 7:06 am Post subject:

The question I was trying to answer was why didn't it catch on.

I had the good fortune to check them out when first introduced and it looked like a great thing. Although we were an early dealer it was a hard sell at the price point and we couldn't move any of them at that time, especially with the clutch issues. Sounds like they've gotten the early challenges straightened out but I still think it's too much power for most kart racers.

But if you really want to know why some things hit and others don't just follow the money going to national organizations, how many pipes are there for KT100 now? Laughing

Cheers,
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John Matthews
Heartbeat Power, LLC.

Brian G. Wilson · Posted: Mon Oct 29, 2012 7:29 am Post subject:

Maybe the Aixro will gain a little more popularity in the US with the introduction of the new motor, the XR30. As I understand it, it is the XR50 that has been fitted with a smaller carb w/restrictor plate and rev limited to 10,000 rpm. It still has the same power curve, but only at 30 hp. The 30 hp XR30 can be turned into the 50 hp XR50 by installing the proper size carb, removing the restrictor plate and 10,000 rpm rev limiter. You say the XR50 has too much hp, buy the XR30 and convert it to the XR50 in the future if you'd like more hp.
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TJ Koyen · Joined: 03 Oct 2004 Posts: 1425

It's an awesome idea for an engine, but like I said, shelling out almost 7k for a go-kart engine all at once is pretty tough for most.

When KF came out, everyone said it was too expensive at 5k for the engine too. That's a big reason it never caught on here.

I think at most you are looking at 3.5k for a new engine package, as a price point that karters would be willing to spend. That's what Rotax is and obviously it's quite successful.
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