[Eric Alexander]

Typically, CHT is only used on an air-cooled engine (such as a Yamaha KT-100 or Briggs LO206).  If the engine is water-cooled, you want to monitor water temperature.

As for tuning, a temp probe in the exhaust header measuring exhaust gas temps is preferred.

[Eric Alexander]

I posted in that thread.  But when the thread stopped, I thought I’d start one in the proper Rotax forum to gauge what other Rotax drivers were thinking as this moves forward.

Like you mentioned, I too am surprised by the lack of posts.  A lot of the 2015 rules packages and schedules are starting to appear and looks as if many are side-stepping the new Evo engines to see how things turn out – which doesn’t bode well for Rotax in 2015 IMO.  My local track is getting behind the X-30 after being a big Rotax supporter (which isn’t surprising considering they’re spear-heading the IAME-East distribution).  Its just bad timing all around as far as Rotax is concerned and I guess that’s going to factor into where I eventually land.

I wish I’d see more support from the karters, but honestly the lack of it is a bit disconcerting.  Seems the market is speaking – so to speak – and the ball is squarely in Rotax’s court to make this work. Like I said, I’ll be upgrading my motors.  But beyond that, I’m beginning to wonder if at the upgrade price points they’ve release, its still not enough to maintain market share in a what turns out to be pivotal year for brands and alliances.  Time will tell, but If I were Rotax (and MaxSpeed here in the States), I’d be watching, listening, and responding quickly over the next few months.

I’d still like to hear other’s thoughts on this.

[Eric Alexander]

Maybe by 2016 there can be a class for unsealed engines with starters.  Someplace where older Rotax and Leopards can race.  We can call it TaG. ;-)

[Eric Alexander]

I view the EVO to past 125 MAX motors more like the X30 to the Leopard.  Its meant as a replacement and they took the opportunity to make wholesale improvements.

[Eric Alexander]

I’ve been expecting something like this ever since that Rotax survey was circulating last year.  And honestly, I think everything looks pretty good.  With IAME coming on strong and introducing the X30, it was clear Rotax was going to re-engineer the 125 MAX platform.  Its proven to be a good platform for the past 15 years.  But it was time to make some changes to address consistency and drive-ability issues people had with it.  And it looks like that exactly what they’ve addressed.

It would be nice to see some incentives to help existing owners upgrade, but it appears the inventory’s not there to do that just yet.  But it wouldn’t surprise me to see something in the future.

The piston is “no-brainer” –  and will happen for all future rebuilds regardless.

The carb to me is a must have, as it has always been the source of the jetting issues.

The electronic power valve is a nice feature, but is not that critical as to need it anytime soon on an existing engine (so long as you’re the type that maintains your RAVE valve on a regular basis).  So that removes it, and the new ignition coil and box, from the must-have upgrades list.

Same for the exhaust.

All that’s left is the crank and con-rod.  That might bite a bit in the rebuild charge, but that’s the biggest chunck of change IMO (and probably a significant portion of the power gains).

Still, the Rotax market is going to be a bit crazy for the next year.  The bottom’s going to fall out for alot of spare parts.

[Eric Alexander]

Maybe: http://strosin-larkin-and-sipes4012.myshopify.com/products/kart-chassis-setup-theory-and-practical-guide

Looks like a good read.

[Eric Alexander]

New update: http://www.racer.com/imsa/item/110949-memo-gidley-update-two-more-surgeries-all-going-in-the-right-direction-throttle-down

Also the Robin Miller interview from the Indycar race at Sonoma.  So good to hear of his continued progress.

[Eric Alexander]

The only difference is the RAVE power valve. But to add that you need a Senior cylinder block. New, the items run about $900 in parts. Now you can find these used. RAVE assemblies run between $75 and $150. Cylinder blocks anywhere from $150 to $400. I’ve recently heard that Rotax has relaxed the cylinder block casting serial number rules, so you should be able to use any year.

Now add to this labor and resealing costs. Thats going to run you another hundred or two. At this point you might consider a top-end rebuild just to match a new cylinder to the new block I.D. That will probably only cost you a hundred more.

[Eric Alexander]

I set one of my karts up for a friend. We fit a Tillett T10 XXL seat and so we needed to expand the struts a good bit.  I did fit an old axle over the right side strut and bend it outward a bit.  Mind you, on this CRG frame it was a bit difficult to move it as to the way the strut is fitted to the frame.  But we did end up getting just under an inch of rightward expansion.  We scaled the kart and still had more weight left than right, so it was the right thing to do. With a driver of his size you’re already over weight minimums, so no chance to add weight and re-balance without that weight penalizing you’re laptime.

Best of luck.

[Eric Alexander]

I’d be on the fence about the frame.  The price point is good considering its a 2013 kart, but that frame has been raced hard to get that amount of flat-spotting in a single season.  If it were me, that amount of flat spotting would bother me.  But again, a 2013 Tony Kart is going carry some value regardless.  In the end its up to you, But I think you can find an older kart in much better shape for the same – if not less money.  $2500 to $3000 can buy a nice used kart if you’re patient and look hard enough.

I’d also listen to guys about buying a kart serviced by your local track.  And also about buying one already set-up for the engine class you intend to run.

 

[Eric Alexander]

Absolutely!  Thanks Troy.

[Eric Alexander]

Some days I have waayyy to much time. LOL!

 

[Eric Alexander]

Great to know. Thanks!

[Eric Alexander]

Here’s some pictures to underline what I’m asking about.

[Eric Alexander]

LO206 is a good option at GoPro Motorplex.  They’ve just started a Wednesday night series around the rental karts that features an LO206 racing karts class.  Spec Hoosier EL26 hard compound tires and a simple walk-up $40 registration fee.  Its about as inexpensive as kart racing can be.

[Eric Alexander]

I use products called Rapid Prep and Rapid Tac.

Rapid Prep removes the oils and grime on the surface.  Its works so will that I bought a large size and use it to clean the plastics regularly.  Preparation of the surface is the most important part to get the graphics to adhere.

After the plastics are clean, spray the surface with Rapid Tac.  This will allow you to slide the graphic over the surface to line it up correctly.  After that use a small, soft squeegee and work from the center out to remove the application fluid and air bubbles.

Once down, you can use a hair dryer to set the adhesive.  Also at this stage you can use heat to mold the graphic around any corners where it doesn’t sit well (most graphics will have a split in the vinyl to accomplish this over complex shapes).  Don’t use too much heat as you’ll stretch the graphic and then it will never lay flat over the surface.  Always work towards the split.

[Eric Alexander]

Some use an old axle (or any long steel pipe) that you can get some leverage going with.  Be sure to wrap it with some thick fabric like a towel to prevent scratching the frame.  A quick search on YouTube will give you result showing how its done.

[Eric Alexander]

Thanks Kirk.  Nice to hear the benefit.  Sliding the rear through the corners is exactly what I’m trying to resolve.

[Eric Alexander]

I second David’s comment re: Briggs LO206 class.  Its affordable and the formula will allow her to focus more on racing rather than tuning.  Rotax would be fast enough that tuning the kart becomes a bigger part of the equation and that might make it less fun if she can’t be competitive.

As for chassis: at GoPro Motorplex I’d go with Arrow as they can provide a lot of support for the chassis there. And the majority of garage owners there have Arrow karts so you can get more advice for set-ups and what not.

[Eric Alexander]

So another thought is the starter bushing wire has started to come undone.  It might even be touching the starter cover (which *might* short out the electrical system and cause the kart to stop running on the track).  If you only have a thread or two of the braided wiring in the bushing connected I could see that causing the starter issue.  And the bushing wiring is a known item that wears over time.  If anyone at the track has a spare starter you could try swapping out and seeing what that does.

If you race Rotax, a spare starter is a must for your spares kit.

[Eric Alexander]

First two things I’d check are fuel pump and battery.

Fuel pump: when the diaphragm wears out it stretches out and stops pumping fuel efficiently.  It shows up as miss-firing and hesitation on the track, and if unchecked eventually leads to the engine just dying.

But a bad battery will do the same.  If it will not hold a charge it will start out strong and quickly fail to run the kart out on the track.  Also a bad battery can have enough voltage to spin the starter but not engage the flywheel and therefore not turn the engine over.

After checking those two, I’d start looking at the wiring harness.

[Eric Alexander]

Will do.  I haven’t gotten back to the track, but I wanted to let you know something you said clicked.

“Typically things that will make the kart turn-in better will conversely hurt your exit”

That’s really good info.  With the lack of grip on the track, I was really focused on entry.  When I had the entry working well, the push on exit became an issue.  I do think the rear was lifting too quickly – and therefore down to soon.

None the less, really valuable words there.  Thanks again.

[Eric Alexander]

Thanks TJ.  I was hoping to get someone like you to chime in on this.  I’ll try the camber adjustment and then start narrowing the rear incrementally since I’m at the max now.

[Eric Alexander]

Buy yourself a sonic cleaner from Harbor Freight for cheap (like under $50.00).  Then break down the carb and let the sonic cleaner do its thing on all the parts except the needle and the gaskets.  I do this on a regular basis using dawn dishwater cleaner.

[Eric Alexander]

The cylinder MY is cast on the right side on the intake.  Its a two digit number inside a circle.

The main case has a serial number stamped on the right side just ahead of the clutch fly wheel (on a smooth flat area).  You’ll need to reference this serial number with a Rotax agent to identify the MY of the casing.

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