[Christian Fox]

Well, he’s 10, and he’s been known to say “Dad, my motor sounds weird.” Honestly, you could probably get by with 89, As Rotax are pretty low compression engines. I like the idea of race gas; consistency, smell (not important, but nice), and doesn’t leave your carb sticky with ethanol residue. I’m sure it’s easier on the motor, too. But we’ve always had much better performance with pump gas, so pump gas it is when we can use it.

[Christian Fox]

Lowest octane you can get away with without knocking; I like 91 pump gas. Lower octane fuel ignites faster (the reason it detonates in high compression motors). MS93 smells better and keeps your carb clean, but Rotax motors love pump gas with ethanol. It’s also much easier to tune with pump gas; the ethanol makes your carb less sensitive to weather, so jetting doesn’t need to be as precise. There is a scientific explanation for this, but I don’t know what it is. If you are going to run at a national event where they mandate MS93, plan to go one jet leaner than you would on pump (no oxygen in race gas).

[Christian Fox]

Mark, the current dellorto vhsb 34 carb doesn’t work in an on/off set-up; it’s too big. Kids have to roll onto the throttle or else they’ll just bog down. Supposedly the new Evo carb can be stomped, at least more so than the current carb.

[Christian Fox]

Clark, that is interesting. Do you know if your friends were doing a before upgrade/after upgrade comparison with a specific Micro, or were they comparing 2 completely different motors (a new Evo Micro vs. an older Max). Because slight motor variation is so magnified in Micro, you really need to do a before/after with one motor.

[Christian Fox]

Rules say 128mm min to 135 max (and that’s for mini-max, I didn’t see anything specified for Micro), but the standard width for most cadet size wheels is 130mm, so that will be fine, and widely available different manufacturers (OTK, Douglas are 2 examples).

[Christian Fox]

I agree with TJ’s initial reaction; this show is an anti-promotion for karting. Let’s see, in the first 20 seconds the first two things they emphasize are A.) how expensive karting is, and B.) how dangerous it is, complete with footage of a flipping kart. Follow that up with clownish loud mouths obnoxiously promoting their kids and you get a lovely picture of our sport. All I can say is I’m glad this show wasn’t around when we decided to make the jump to outdoor karting.

That said, it’s a reality show, which means its purpose is to make the viewers feel better about themselves  because they aren’t part of the freak show on tv. It’s not there to promote its subject material.

 

 

[Christian Fox]

Mark, that’s the big question. According to Rotax, the upgrade will make them equal. Internally, the piston is slightly lighter, the con rod has a new coating, and the crank bearing is slightly different. A couple of engine builders I’ve spoken too think a good, upgraded Micro will still be good relative to an Evo. I suspect a high $$, part-matched Micro franken-motor that kicks ass now will still kick ass when upgraded. The big question is the coil; you don’t get the new one in the Micro upgrade. The timing hasn’t changed, so it’s not a required upgrade, but Rotax claims the throttle response will be better.

[Christian Fox]

I don’t know of anyone with the new parts yet, but the HP is up for every motor in Evo form. Biggest difference will be in Micro (lowest HP, biggest % gain). Micro is going from 6.8 nominal HP to 8.0 HP, an 18% increase. Micro is the only engine class that Rotax claims will have a performance gain (which is strange given Hp is up in all the evo motors). Hope that helps.

[Christian Fox]

Tony is correct; either your float  is stuck or your needle valve is bad. I’ve had a needle spring get sticky before. If that happens, you will either run super rich or spill fuel like your are seeing. If you use pump fuel and the fuel has sat in the carb for a while, the inside of your carb can get green and sticky from the ethanol. Carbs don’t like sticky. It’s pretty easy to strip a rotax carb (they’re huge) and clean it out. Here is a link to a good video if you are unsure about how to do it:

 

[Christian Fox]

Hi Eric, there is a thread in the general discussion section:

https://new.ekartingnews.com/forums/topic/rotax-max-new-upgreads-2015/

I have been surprised by the somewhat muted reaction to all of this. I guess it centers on the uncertainty of the performance of upgraded engines vs. new evos. Until we all see, there isn’t a whole lot to talk about, I guess. I have three motors and will be upgrading all of them, but I don’t see much hope for good re-sale value for the old parts. It seems pretty clear that a non-upgraded max will not be competitive with an evo, so I don’t know how many guys will wants the old parts.

[Christian Fox]

Sebastien, you can plug the GPS directly in to the Mychron 4 and not even use the data hub. The downside to this is you nuke the 9 volt battery in the Mychron very quickly, whereas the data hub method requires you to connect to an outside battery. I’m paranoid about running anything off of my kart’s battery, so I just use the direct plug-in method and carry a bunch of extra 9 volt batteries around in my toolbox. Tony’s example really is the best; the data hub is handy to have and makes downloading data and uploading track maps much easier. This winter I’m going to figure out a way to mount an RC car battery somewhere to power it. Most people claim it’s fine to run off of the kart’s battery, but I’ve had a few battery related issues and don’t want to take a chance.

[Christian Fox]

We will be sticking with Rotax for 2015. My son will be in micro for one more year, and this past season we had a very good, competitive group of kids. We were getting between 10 and 15 kids for club races at OVRP, and the same for the Northeast Rotax regional series. Between 12 club races, 12 regionals, nationals, and 1 or 2 FWT races, we will have all the racing our schedule can handle next year. I’ve been getting poked and prodded to buy a Mini Rok, but honestly I don’t have the time or interest to deal with another package. As long as the EVO stuff doesn’t scare people off (it shouldn’t), I don’t see any reason why we shouldn’t have a good crop of micros for 2015.

[Christian Fox]

whoops, sorry, that didn’t come so good…

prices:

Micro $177

Mini $ 170

Junior $ 388

Senior $470

DD2 $473

[Christian Fox]

It’s pointless to wonder/argue about the performance of a non-upgraded Max vs. an Evo. The Evo will be faster. The only thing to wonder is whether an upgraded Max will compete with an Evo. I suspect it will. The following are the prices for upgrade kits. You get to buy one per serial number. Prices are pretty good:

 

<span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”>$176.67 – Micro MAX, consists of VHSB34 XS carburetor, exhaust socket and ring, and perforated tube;</span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”> </span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”>$169.46 – Mini MAX, consists of VHSB34 XS carburetor, exhaust socket and ring;</span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”> </span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”>$387.82 – Junior MAX, consists of VHSB34 XS carburetor, ignition upgrade kit 1 & 2, Junior MAX E-box;</span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”> </span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”>$470.19 – Senior/Masters MAX, consists of VHSB34 XS carburetor, ignition upgrade kit 1 & 2, MAX E-box, E-Power valve;</span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”> </span><br style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;” /><span style=”color: #505050; font-family: Arial; font-size: 14px; line-height: 21px;”>$473.62 – DD2/DD2 Masters, consists of VHSB34 XS carburetor, ignition upgrade kit 1 & 2, MAX E-box, E-Power valve.</span>

 

[Christian Fox]

The big question is whether an upgraded Max will keep up with an Evo. I suspect if you have a Max with a good crank and barrel, it will be fine. The guys hurt by this are the guys that spent a ton of $$ to find the magic coil and/or carb for their Max. They are back to square one with the new parts coming on line if they plan to run with Evos.

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