[Rob Kozakowski]

Aaron, where does it say that?

All I can find is:

Mini and Micro Appendix:

6.9 j) OLD CARB – “Main jet is free but limited to those supplied in the Rotax Micro MAX jet package (ROTAX part 281476, which includes main jets: 115-118-120-122-125-128-130).”

Right below, it says for the NEW CARB “Regulation for XS carburetor: Section 6.8 fo the 2015 RMC Technical Regulations apply.”

In the RMC Tech Regs:

6.8 talks about the intake silencer, so I’ll assume that it should be 6.9…

At 6.9 there is nothing that talks about main jets.

So, it looks to me that:

1) NEW CARB – main jet is open.

2) OLD CARBS – main jet is restricted in MicroMax only.

[Rob Kozakowski]

Michael – I think one thing you need to consider are the forces in the static vs. the on-track situation.

With the kart sitting still on the ground, no matter how much caster, ackerman, etc. you have, when you turn the wheels, it won’t roll as freely as it will in a straight line.  I think the only point the “books / setup documents” are saying is that a kart naturally wants to drive straight ahead.

Yes, if you take a lot of the geometry out of the front end, it will roll “easier” under no load with the wheels turned than with lots of geometry (apply a simulated load and results may change)… but still not as easily as with the wheels pointed straight ahead… the kart naturally wants to move in a straight line… push it with the wheels turned, and the wheels will straighten themselves out very quickly!

What this little demonstration isn’t doing is telling you about the impact of adjusting caster, ackerman, toe, front track width – those things really come into play when a kart is moving.  That’s where the points that TJ and Larry, etc. are making become relevant.

As to where does the “freeness” of the kart derive from?  I’d say it’s a balance between a LOT of factors… part of it is the front end, part is the rear, part is the overall balance / seat placement, part of it is grip levels – in the track, the tires, the frame, etc.

Yes, you want to lift the inside rear… but (a) there are many ways to do it… and (b) some will make you faster, while some will make you slower.

[Rob Kozakowski]

There are really 2 versions of the Extreme Kart, as far as I can tell…

There’s the World Formula – non-homologated; and the Viper – homologated.  The Viper carries a higher price tag.

Homologation really doesn’t have to mean a lot, but generally non-homologated Euro karts are either older (expired homologation) designs that they continue to manufacture and often sell with basic componentry to offer an affordable kart, or they are designed as 4-cycle / World Formula karts, that don’t require homologation, and being designed for 4-cycle, may not be best suited for higher HP.

I agree with Finch that if I was looking at a budget of $2000-3000 for a chassis for TAG, you’re probably better off going with a 5-10 race old, “big-name”, well proven model.

And if you decide to quit racing after a season, your 15 race old Tony / CRG / etc. will be worth a lot more than your 10 race old Extreme… something that the less serious racer might want to consider.

[Rob Kozakowski]

My impression is that as far as Rotax goes, given the number of Canadians supporting the US-based International Rotax events (the 2 big Rotax winter series – FWT, COA; and the Pan-Am; and there’s also the Northwestern Can-Am series that crosses borders), it’s finally dawning on people that it only makes sense to get rid of the differences between the Canada and US rules.

It seems that Maxspeed (US) and SRA (Canada) are working closer together all the time to ensure that this happens.

[Rob Kozakowski]

I believe that the less expensive versions of the RR Extreme Kart line are a non-homologated chassis, designed on a “global” scale for the World Formula / 4-cycle concept.

I know that Mac Minarelli had a (assumed to be identical, just re-badged with a different decal kit, given that RR builds karts for Mac Minarelli) kart that a few people in Canada were running with the LO206.

They’re a pretty basic kart, base components, aluminum wheels, etc., but there isn’t really anything wrong with that in 4-cycle.  But they do have some adjustability, and yes, they do have a front torsion bar – I think most of the pictures in the ads are of a different Extreme Kart frame!

The kart  could also probably be just fine with a Yamaha can or some other lower powered 2-cycle classes.

It wouldn’t be my chassis of choice if I was going TAG racing though.

[Rob Kozakowski]

Mark,

The Canadian summary sheet (link above) makes it pretty clear (it’s even underlined) in the “Questions and Answers” section…

Last sentence of #2. “For Micro and Mini, if you upgrade your old engine to EVO, you must use a cylinder marked with a lettered production”.

Given that US and Canada specs appear to be the same, I’d say it’s pretty clear what the intent is.

At official RMax events, the kids have to run the newer cylinders, if they want to run EVO kits.

[Rob Kozakowski]

The joys of figuring out which rules apply to your series!

[Rob Kozakowski]

US Mini and Micro appendix… 1.7 and 2.6 on the cylinders…

http://www.gorotax.com/images/downloads/USRMC_2015_Technical_Appendix_Micro_Mini_March16.pdf

[Rob Kozakowski]

It looks like US and Canada are identical… including the requirement for Micro and Mini to have “lettered” cylinders to go EVO, effective immediately… Junior, Senior and DD2 have until 2016 to go with “lettered” cylinders if they want to go EVO.

 

 

[Rob Kozakowski]

Everybody’s advice might be right.

First time in a shifter will make it very difficult to diagnose, if you ‘re still in over your head a bit.

At this point, I’d definitely let someone with a few laps in a shifter try it and give you some feedback.  It could just be the way you’re driving it.  Or it could be an actual problem with the kart / engine.

[Rob Kozakowski]

As TJ says, it absolutely depends on the chassis.

In my Italkart, “in general” the softer axle frees up the rear of the kart, harder axle gives more grip.  That’s the opposite of OTK karts.

More often than not, most of us are best off sticking with the “baseline” axle, which is normally a medium stiffness axle on most karts, and looking to your driving or other smaller adjustments, unless you’re running in a big event on a very “rubbered in” / grippy track, or a very “green” / slick track.

[Rob Kozakowski]

I’ve had confirmation from Italian Motors that they recommend the Rapido V for 4-stroke applications.  If you go to their website, they often have used 4-cycle packages advertised on the Rapido frames.

No need to do any cutting of anything (maybe if you have a mid-00’s Rapido, but not a 2013).  Run a soft axle in the rear.

[Rob Kozakowski]

Walt, don’t go… we appreciate your advice, but I agree 100% with Gary and the others.

I too can remember back to the days when we had to have something (a circlip, etc) at the end of the axle, outside of the rear hubs.

Was that safe?  Absolutely.

Was it overkill?  Absolutely.

The fact is that in all those years, I never saw a tightened hub slide out and off the end of the axle… I only ever witnessed them slide inwards… and when you think about the forces acting on the axle and the hubs when a kart corners, it only makes sense.  We 3-wheel these things on the outside rear, which is “pushing” the axle further “into” the hub.

Now, if you don’t tighten the hub down, anything can happen, but that would be the case no matter where on the axle the hub was located.

[Rob Kozakowski]

Over-complicated.  Too expensive.  While it arguably “solves” one problem, it creates two new problems.  Etc…

The reality is that “some” amount of contact has always existed in kart racing.  And that contact can probably best be classified as either “incidental” = the innocent bump when a driver in front makes a mistake and bogs out of a corner and the guy behind has nowhere to go, or the unintended contact that simply results from close racing like we see in karts = it is accepted, no harm, no foul; or “intentional” = the guy from behind attempting the divebomb pass or just ramming the guy in front out of the way = the stuff that should be punished.

In the old days, pre-bodywork, it was pretty easy to differentiate between “incidental” and “intentional” contact.  And it was rare to see the “intentional” contact because you were likely to get yourself hurt if you initiated it.

As we’ve added more and more plastic, it’s become more difficult to differentiate between the “incidental” and the “intentional” contact, with a further problem being that the initiator of the “intentional” contact was no longer afraid of the consequences of doing so.

While this new front bumper will punish the “intentional” contact, it’s also now punishing the “incidental” contact, as well as punishing the innocent guy who gets intentionally break-checked.

It encourages the lead driver to drive a very “defensive” line (to block) because any contact will automatically result in a penalty to the driver behind if his bumper becomes dislodged.

It discourages legitimate passing attempts from being made in the fear that the guy in front will chop down on you and penalize you for having a dislodged bumper.

At the “real” top levels (Lammers, Fore, Lennox, etc.) the guys race so clean that when the “intentional” contact occurs, it is easy to spot, and the real solution would simply be to punish that as it happens.

Unfortunately, this new front bumper might solve a problem that exists at the mid-pack and less-than-elite level, while creating a problem where none existed before at the elite level.

If you can’t see the issues with this “solution”, I don’t know if you really understand kart racing.

[Rob Kozakowski]

Raw hp numbers mean nothing.  All that really matters is the comparison on the same dyno.

What a lot of people really want to see is 1) Prevo; 2) Prevo from #1 with Evo kit; 3) Evo.  Curtis did 2/3’s of this in his test.

And even then, to really get an idea of the differences, you’d probably have to do it with a few Prevo’s and a few Evo’s… we all know that differences exist in the Prevo’s, and so it’s probably reasonable to assume the same will happen amongst the Evo’s.

One thing that many of us are interested in is whether the gap between a “strong” and an “average” Prevo will be reduced with the Evo kit.

[Rob Kozakowski]

I said the top drivers in the world… you know, the guys who don’t use the chrome horn…

Anyone who saw Lammers, Fore, Lennox, etc. (i.e. some of the top guys in the world – all 3 of whom that had nothing good to say about all the bodywork, and especially the new front bumpers) at the Supernats knows that those guys race real hard, but clean.  The only real incident I saw at this past year’s Supernats in the KZ class (towards the front of the grid) was when Myers bumped Carlton out of the way in the pre-final… needless to say, Carlton went right back at him and had words for him afterwards… because that’s not the way it’s done at that level.

[Rob Kozakowski]

How about the new MXJ wheels?

[Rob Kozakowski]

After the first experience with the new front bumpers on the KZ karts at the Winter Cup in Lonato this weekend, it seems that the fears are being realized.  When many of the world’s top kart racers think it’s crap, it’s probably crap.

[Rob Kozakowski]

Limited to Jr, Sr and DD2, it looks like:

1) carb might give small gains over current “good” carbs in all classes, so probably a decent improvement for the “average” current carb

2) Jr Max ignition system is a big improvement

3) Sr / DD2 get a decent improvement from the electronic power valve

4) new exhaust is just more quiet

5) EVO comes out of the box “ready to race”, where the current engine needs some “running in” time before it gets faster

[Rob Kozakowski]

Interesting…

http://www.kart.co.za/index.php?option=com_content&view=article&id=650:good-news-emerges-from-cape-town-testing-of-new-rotax-evo-engines-and-upgrades-on-existing-rotax-engines&catid=49&Itemid=101

 

[Rob Kozakowski]

Ryan, unfortunately the answer is it depends…

1. One engine may have a performance advantage at one track, while another may have an advantage elsewhere.

2. Rebuild schedules?  How hard to plan to push it?  The Rotax is lower revving, so it should be able to last a bit longer.

3. Costs of rebuilds?  Rotax has to go through a Rotax authorized dealer, and has to be sealed, so it’s more expensive.

4. Ease of tuning?  Really depends on how you define “ease”.  The Max is “easy” to get running, but in order to get maximum performance, you have to test to find what jet to run in what conditions, and constantly monitor air conditions.  The IAME’s are also easy to get running, but are adjustable on the fly – this can be good or bad.  The good is you can dial in your performance on the track.  The bad is you can go too far and possibly seize an engine from going too lean.

5. Other factors:

a) The IAME’s perform more like a “real” kart engine.  Most people find them more fun to drive.

b) Most importantly – who do you deal with (kart shop)?  Unless you’re dead set on one engine over the other, your best bet is probably to go with whatever product you can get support for.

[Rob Kozakowski]

Jim – I’d also disagree with you about this being economically irrelevant.

At the grassroots level, I’d agree nobody would care much who’s making the money.

But at the top levels, it’s surprising how many drivers are loyal to (and dependent on) the shops.  If the shop says we’re not going here and we’re going there instead, their customers often follow suit.

[Rob Kozakowski]

Jim – Is it really Rotax vs. IAME, or is it the shops vs. SKUSA, where Rotax benefits from having an existing program?

My guess is that on the TAG side, many of the shops who pushed for this feel they can make more money, and are thus happier, with the Rotax and Mojo deal than with the new SKUSA/IAME/MG deal.  On the Stock Honda side of things, this also benefits the shops with “Shop MG” tires vs. SKUSA MG tires.

SKUSA has always done a great job running events.  But they’ve now taken a lot of potential profit in the form of tires and engines from their biggest customers  – the shops (remember there are very few privateers running out of their own trailer at the SKUSA events).  The question that will eventually be answered is whether SKUSA has gone too far?

[Rob Kozakowski]

I think the cost is high.  That said, I also thinks it’s justified.

All I can say is get involved on a club’s executive, and you’ll quickly see that the costs charged to the competitors are not all that out of line with where they should/need to be to keep the clubs running.  And the costs for some clubs are higher than others for a reason too.

One thing that allows club events to be cheaper for the entrants is that they are generally run predominantly on a volunteer basis.  While most clubs are fortunate to have these volunteers who rarely get the thanks they deserve, as the saying goes, you do get what you pay for.

At a National event, you want quality and consistency out of your officials – race director, tech personnel, all the way down to registration, etc.  This means to keep the same crew, you are flying people around the country, putting them up in hotels, feeding them, and paying them for their time.  It’s also only fair to the host club or track-owner that they get something for shutting down their facility to regular use.  Some bigger events will beef up the amount of paid medical personnel on site.  Etc… more costs to hold the event, meaning higher entry fees.

Karting just doesn’t bring in outside sponsorship money at the same level as other sports, which means that a higher portion of the costs have to be paid by the entrants.

[Rob Kozakowski]

I’m no czar.  I have ideas, but I can’t sell them.

Part of the reason we have the mess we do is because we’ve allowed each group at the bottom to push things up… in about 100 different directions.  It’s probably great for the tuners out there, who can be kept busier than ever with all the competing “top level” series’ events we have today, and it’s great for guys with real deep pockets who can afford to race different series almost every weekend.  It’s not great for the great drivers with minimal funds, who don’t get much recognition anymore because they have to choose only one of the many now-diluted series out there.  It’s also not great for the average-joe karters, who might occasionally want to venture to another track once or twice a year, but can’t anymore because their’s no class or nobody to race against for them at the other track.  We’re benefitting the few, at the expense of the many.

I currently race Rotax, but admit to having no love for it.  That said, in Canada, where our ASN is pretty strong, we have a lot of consistency across most of the country, with Rotax and L206 (I also race the L206 and love it) being the standard for 2 and 4 cycle racing, respectively.  Although clubs have the ability to add additional classes locally (shifters, Honda 4 cycles), the clubs are based around these 2 engine packages, which can be raced anywhere, from the club up to the National level.  Again, while I don’t love the choice of Rotax, at least it’s clear what you need if you want to race, with consistent rules everywhere you go.

In Canada, “overall”, I think the top down approach has been beneficial, with much less fragmentation than in the USA.  We actually have National Champions!  In my opinion, we’d be better off in Canada if we had a better option than Rotax for 2-cycle, but what that better option would be is far from obvious right now, especially when Rotax is so prevalent and everyone has so much invested in it.

[Author]

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