IAME KA100: The Future for Grassroots 2-Cycle Karting?

Three-year-old engine ready to make debut in United States during 2017 season


The saying goes like this…‘speed costs money’. The more money you spend, the faster you can go. Karting is no different, as a wide range of speeds and costs are available when you want to hit the race track. The sport provides an incredible option for people searching to fill that need for the adrenaline rush you can only find when you drop down the visor and hit the gas pedal. When karting first began in 1956, racers built their karts from the ground up, machining and welding together their frames while utilizing chainsaw engines and other small powerplants to push their four-wheel machines around local parking lots and parks. Fast forward 60 years and there numerous chassis manufacturers and engine producers around the world, all dedicated to the sport of karting.

The introduction of the Yamaha engine began a craze that motivated many different manufacturers to create a 100cc piston port engine of their own. Among them was the joint effort between Italian American Motori Engineering (IAME) head engineer Renato Azzolini and IAME USA importer Lynn Haddock. Their creation was the Komet K71 powerplant, introduced in the mid-1980s, which found success quickly in the United States and was adopted in Europe by the CIK for its international junior racing class.

The engine took on its new look in 1996 when California’s Horstman Manufacturing Company utilized the K71 as part of their ‘spec racing kit’ – the Horstman Piston Valve (HPV) engine – which featured a Horstman-manufactured low engagement centrifugal dry clutch and a spec exhaust produced by RLV. It was one of the first spec packages introduced in the karting market. The HPV engine was successful coast-to-coast as both the IKF and WKA adopted the engine, utilizing it in all of their class age groups. Eventually, the TaG craze took dominance over the US market, and eventually IAME and Horstman ended their relationship in the late 2000s before Haddock Limited retained the rights to the now KPV-branded engine. WKA has dropped the HPV/KPV engine platform from its national class roster, although the IKF still recognizes the engine at its events. Clubs and tracks across the country still provide a place for the 100cc Piston Port powerplant to come and play.

Prior to the 2015 season, the IAME KA100 ReedJet engine was introduced for the Australian karting market with the support of the country’s sanctioning body, Karting Australia. The Yamaha engine was utilized in Australia, dating back to 1986, and remains an eligible powerplant at the club level alongside the KA100. Direct drive was the popular choice for the Yamaha divisions, something that went away here in the United States well over a decade ago.

Two reasons played into the development of the IAME KA100 – parity and cost. On-track performance was a major issue, as engines that were nearly 30-years-old were selling for up to 10 times the retail value of a new engine. Many of these ‘special’ engines would only run at major events and were shared between families and teams. This type of parity fueled a rise in the cost of Yamaha racing. Racers would invest thousands of dollars to find and develop a fast Yamaha engine.

“We decided that we needed an out-of-the-box solution that provided good parity and at a reasonable cost that was not increased by the need to blueprint the engine and re-engineer it to get the performance out of it,” added Kelvin O’Reilly, Chief Executive Officer for Karting Australia. “The decision to replace the Yamaha was not one that was taken lightly. The research was conducted for several years by both the former and the current administrations of the sport in Australia to ensure the correct plan was put in place for the long-term future of the sport.”

KA100 action in Australia (Photo: karting.net.au)

Everyone in the United States is familiar with the success of multi-time Australian David Sera, who has won stateside as well. We asked his viewpoint on the introduction of the KA100 to Australian karting; “The engine parity stands out for me. No longer are newcomers in the sport having to search for these proven engines, they’re now able to concentrate on driving, knowing the engines are all very similar.”

Looking at the KA100 engine, there are five things that stand out when comparing it to the Yamaha KT-100 – solid exhaust, clutch, inlet, starter, and overall power. The KA100 kit comes with a full length solid exhaust, similar to that of the Mini Swift engine. This eliminates the loud can muffler that the Yamaha utilizes. The clutch on the KA100 is the same on the IAME X30 engine. There are no adjustments needed for this clutch, which is the complete opposite of the Yamaha clutch. Either wet or dry, friction disks and springs make clutch maintenance a must in order to ensure your Yamaha engine is performing at its best.

Of course, the inlet system is completely different for the KA100 to the Yamaha. The KA100 is a reed valve engine, similar to its larger IAME TaG engines, while the Yamaha is a piston port engine. The carburetor is a Tillotson HW 33A – designed just for the KA100 engine – moving away from the Walboro WB-3A on a Yamaha. Another different component is the standard IAME airbox, something that comes with the KA100 kit, while with the Yamaha, is an added expense.

The biggest difference, and what could be the greatest selling point, is the onboard starter. The Yamaha has always utilized the external starter, making it impossible for the average racer to just jump in and go like the TaG karts. The KA100 comes with the electronic onboard starter – similar to that of the IAME TaG engines.

Below are some specifications related to each engine:

model Reedjet KA100 – Clubman Yamaha KT-100
description Single cylinder – 2 stroke Single cylinder – 2 stroke
weight 48 lbs 21 lbs
bore Ø 48.20mm Ø 52.00mm
max bore Ø 48.53mm Ø 52.90mm
stroke 54.00mm 46.12mm
displacement 98.53cc 97.9cc
ports 2 2
inlet system Reed Valve Piston Port
lubrication Oil mixture Oil mixture
ignition system Analogic with adjustable timing TCI
transmission Centrifugal Dry Clutch Centrifugal Clutch (wet or dry)
cooling system Air Air
starter Electric External
carb. model Tillston HW 33A Walboro WB-3A
max power 22 Hp 17 Hp
max torque 15 Nm 9 Nm

Taking all the different factors between the two engines, let’s look at the bottom line – cost – using the CometKartSales.com online store as our guide for the different costs. The KA100 is available now for $1695 (promo price). IAME has stated the retail price will be $2,295. The engine kit includes the carb, clutch, exhaust, and airbox. A Yamaha engine at retail is $750 and includes the carburator. Add in a clutch ($315), exhaust muffler ($79) and an airbox ($30), and the difference shrinks down to about $520.

When you look at the cost ladder for engine packages in karting currently, the KA100 falls in between the Briggs LO206 ($945 / includes everything to mount to kart), a TaG ($3,195 for IAME X30) and a shifter engine ($5,550 from MRC for Honda CR125).

For 2017, the United States Pro Kart Series has elected to introduce the KA100 engine as a replacement to the Yamaha in the Senior Pro class. Last year’s numbers in the Yamaha Pro went from 17 at the opener to five at the finale. The racing can be incredibly tight, but weekend after weekend it continued to be the same three or four in the hunt for the victory. Now, the KA100 is set to be the headline 100cc category for the series entering its fifth season.

“From the very beginning, the USPKS has set out to be an industry leader, and a pioneer in the sport,” stated USPKS owner Mark Coats. “The KA100 is a major step forward in 100cc racing, but it’s a new package to the American karter.”

The new engine has brought veteran racer TJ Koyen out of retirement, albeit a six-week one at that, who is one of the first drivers to commit to the KA100 class at the USPKS championship. “I think the engine addresses some of the shortcomings of the Yamaha package that racers have been complaining about. It’s faster, hopefully more reliable, and offers a nice in-between for drivers not ready to commit to the cost and complexity of full-on 125cc TaG racing. It reminds me of KPV, which was my favorite class to race in. And with the harder MG Red tire that the USPKS is running on, I think the whole formula for the class is spot-on and should provide a ton of fun.”

Koyen’s point about the ‘in-between for drivers not ready for TaG’ is exactly why I think this engine will be great at all levels of the sport – club, regional and club. Right now, we have a great engine package ladder system based on speed, maintenance, and cost – Briggs LO206, Yamaha/KA100, TaG, and Shifter.

We are seeing a number of new racers at the adult age group entering the sport for the first time, or returning, thanks to the simplicity and ‘out of the box’ parity of the Briggs 206. Eventually, racers look for the next step up, and speed-wise, that would be the Yamaha engine. Many feel the Yamaha platform is based around the engine builder, and not the driver/kart combination we see in 206 racing. We are seeing it more now in the TaG world, even with Rotax looking for engine parity moving into the 2017 season.

Many feel that the KA100 is just the next fad that will eventually go away, as the Yamaha remains the lead 2-cycle engine for grassroots karting. The Yamaha is still standing strong compared to its other piston port 100cc engines. There are still thousands of them around the country, with parts still readily available, and new powerplants still being manufactured. Time will tell, and we’ll be watching closely, as the KA100 makes its United States debut in April at the GoPro Motorplex.

10 thoughts on “IAME KA100: The Future for Grassroots 2-Cycle Karting?

  1. I still have a few reservations. Though engine prices are low now, they will increase a significant amount if they reach parity with Australian prices, save for the exchange rate. Kracer.com.au has a price of $2,990, that’s almost $2,300 in USD, a 30% increase from the current listing. Of course, parts are more expensive than the KT100, and so we have to hope that rebuild times are as infrequent as have been estimated.
    However, our industry has a habit of being overly optimistic about those times. Then there’s the added weight. I can’t speak for other clubs/series, but Yamaha Sr. drivers already put large amounts of lead on the kart. USPKS has published a weight of 360#, which I believe is a 10# increase from the Yamaha Sr at USPKS in 2016. One of the selling points of the Yamaha was the light weight, so that the kart would feel like a kart should. Regional and club races will typically add weight from the national level.
    I don’t know about the general consensus regarding onboard starters, but I don’t get the attraction. You still have to prepared for it to fail at any moment, so you still need to shell out for the external starter. So all it does it add weight to the kart with its starter motor and battery.
    They’ve got me with the clutch, though. I’ve been a proponent for doing that to the Yamaha for a long, long time.
    If the engine price stays down, and the weight drops 5-10#, I would be a lot happier. Ditch the onboard starter, and it would be near perfect.

    • Thanks for the comments Peter. Right now, the promo price is certainly a deal. In the long term, I could see this engine growing popularity. If, like the 206, you can take it out of the box and race it, that helps the kart shops looking to grab a new person to the sport. Let’s face it, if your 35-years-old and want to start karting, and the LO206 is too slow for you, what options do you have? Yamaha KT-100 is it – and that’s not ‘Out of the box’ style engine. This really seems like it is, but time will tell.

  2. Peter I agree with your comments except the one about weight. I know that 2 of the top 5 at Route66 (both have committed to USPKS for 2017) last year had no weight bolted on. With this motor weighing 27lbs more and the class weight only being increased by 10lbs… Seems like a few racers will be at a major 17lb disadvantage before hitting the track.

    • As a 200lbs driver, I have had to add weight to a kart to make the Yamaha weights when doing the EKN On-Track tests in 2015. You look up and down the grid, some karts have 50lbs of lead bolted to the kart to make the weight. The 27lbs. difference may be a factor, however, like many other classes the minimum weight can be change. Again, we have to wait and see what happens once we get this engine on the track.

    • Peter,
      The IAME promotional price at participating IAME dealers is $1595.00. That is a awesome price. I’ve seen this engine and it has so much potential. It would be a great Masters Engine Package & a great option for regional racing vs. a X-30 or other TAG Engine Packages. As the USPKS becomes an IAME Series in 2018, this engine will also be in the junior class. We are getting a lot of demand for this in the Route 66 Sprint Series, but I don’t see how that can happen this season.

  3. I have been watching this motor in Australia and I have been hoping they would bring this motor to the US market. My son is a Jr 2 driver 13 and going on 14 this year. We have been racing the Lo206 package for the last 2 years and will be racing it again this year. We are wanting to move him into 2 cycle for the 2017 season when he will turn 15. After seeing the speeds of the Tag Jr’s on the restricted X-30, I as a parent am not ready for him to make such a huge leap from the speeds in the 4-cycle classes. Our Jr. drivers need a ladder system so the increase in speeds from one age group to the others is more gradual. I have been wanting a strong 100cc package to come to the market, with out all of the issues of the Yamaha and KPV. I also drive and occasionally race in the Lo206 adult class. A few years ago I had a Leopard package and raced in the Masters Tag class at my local club. The motor was a blast to drive but at some levels, the power and hard braking is a bit much on the body of us racers who are getting on in age. I will be 55 this year. But we still want to go faster and have a bit more throttle response than the 4-cycles provide. This is where the Kt 100 and HPV’s used to fill that position and I think the KA 100 will help our sport in the US . A motor designed for the current racing market, with better manufacturing and parity. It gives us that package in between the grass roots 4-cycles and the screaming fast 125cc tag motors at a reasonable price. I will say right now I hope Tom K from SKUSA will promote this motor in 2017 and beyond and provide incentive packages like the USPKS is doing now for the KA 100 and Tom has done for the X-30. I think the West Coast will embrace this motor and make it a mainstay in US Karting! We are on board and just waiting for our chance to buy into this concept for myself and my Jr. driver!

  4. i think the weight is including the clutch, battery/starter and the little cover. thats easilly 10 lbs right there id assume. Those things blow all other piston ports out of the water, we had a few up at NHMS this year and they lapped us in a 15 minute race lmao

  5. Ba Humbug…..
    How is this supposed to be good for karting?
    Costs over tice what a Yamaha does.
    Probably the same on service parts.
    Oh, I get it….
    Too many KT100 in the country. Too easy, and inexpensive for someone to start off with a KT100, that they maybe pay $350 for.
    Need to milk kart racers for all they are worth, lets change the rules, make anything common illegal, so they can buy all new stuff.
    Yup, that’s good for the sport….

    • No one is saying to get rid of the KT100. The issue is the perception of the engine at the national level is that you must have a ‘unicorn’ engine in order to be fast. I don’t believe it, but numbers are showing with less drivers racing the category. I think at the local level, Yamaha can continue to run as racers there are not sending engines off to get rebuilt every weekend. The KA100 can be run right out of the box. Sure, it may need work after some time, but I don’t think it requires as much work done to keep it as competitive as the Yamaha does at the national level.

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