Home Forums TaG IAME x30 vs x125T-MX

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    • #42253
      Joe Morales


    • #42293
      Jim Derrig

      The X125t is a noticeably stronger, smoother motor, as strong or stronger than the Rotax in the midrange and matching the X30 in top end, so it’s the best of both worlds.    I’ve found myself overtaking Rotax’s on parts of the track where they used to just drive away from me, while still enjoying that IAME-like extra top end.

      I only have one race under my belt on the X125t, so I’m still learning to tune it.  My motor seemed to have a overly-drastic (and very unforgiving) power drop when off pipe, but I suspect that was partly due to a jetting issue, my unfamiliarity with the motor, and (admittedly) my not exactly being a national-caliber driver (I’ve got a new chassis and I’m learning that at the same time).   So the X30 might have a low-rpm advantage over the X125t like it does over the Rotax, but I can’t be sure at this point.

      I like the simplified ignition system on the X125t, but there’s a trade off as it doesn’t charge the battery like the IAME selectra system does.  On the other hand, the motor seems to start very easily so I had surprisingly little battery drain over the course of the day and charging wasn’t an issue.  I still bought a trickle charger for overnight recharges though, which I never had to worry about when running IAME motors.

      So I’ve got a lot to learn but I’m not regretting my purchase.  If the X125t is legal in your series it’s the clear choice in my book, especially since Italian Motors is running a trade-in program.

      Update March 1, 2015:  After some practice and another race I’ve confirmed that the power drop I mentioned earlier is at least partly due to learning to jet the motor correctly.  It does not pull as smoothly from low rpm as an IAME, but the Leopard driver’s trick of the pole sitter using a very slow formation pace (which puts the Rotax rpm underneath the power valve) does not work when used against the X125, or at least not much, so the power band is not falling off a cliff, as I had feared in my prior post.

    • #51694
      Jim Derrig

      A member PM’d me for an update so I figured I post it here.


      I have 13 hours on the motor now.  I’m totally sold on it so far, and everyone I know who has switched to it has gotten faster as a result. Absolutely no reliability issues–starts easily  every time and goes like crazy as long as you get the jetting right.  Now that summer is hear I barely even run down the battery–it charged in 5 minutes after the last Saturday’s race.


      I had fuel consumption issues early on but that turned out to be a jetting issue and now that I’m getting that down the fuel consumption is similar to a Leopard or Rotax.  The engine is very strong from 9000 to the 15500 rpm redline, especially in the midrange.  The weakness is similar to a Rotax in that the power band falls off a cliff below about 6-7000 rpm, so I’ve been in one situation where I had to gear it so I was redlined ¾ of the way down a straight because I needed to keep the rpm’s up on some slow corners.  That said, I turned my fastest laps ever at that track and was right in the hunt for the win.


      I’ve had a couple situations where the engine bogged down and semi-stalled due to flooding–the Tryton 27 will dump loads of fuel at low rpm’s and when you get below the power band the intake air velocity goes to hell and that in combination with the Tryton causes flooding.  This hasn’t been a problem for me when racing because I’m always careful to keep the engine from loading up during the formation lap, but a friend of mine who is less attentive to this issue (see below) managed to “stall” during a start and went from 2nd to last in about 3 seconds.


      I checked the clutch recently and it looks new.  I’ll probably change it at 15 hours purely as a precaution.


      As for factory support, you have to realize that my home track is SIMA which is built next to the Italian Motors (Italkart) North American warehouse.  The X125t is IM’s baby–Mike and Claudio Valiente took a Maxter KF4 motor and modified it to their liking–so I’ve been somewhat of a early adopter for the motor and they are interested in my feedback.  Beyond that, since the motor never breaks there hasn’t been much support to ask for.   We’ve traded a bunch of jetting info because they are trying to build their knowledge of what-works-where.  My experience with IM customer service has always been great and they ship almost everything for free. With the trade-iin program for this motor I don’t see how you can lose, so long as it is legal for the series you are running in.


      That said, one of my racing buddies has had less luck than me, primarily because he can’t seem to get the Tryton carb adjusted.  However, he never does any maintenance while I flush my carb after every race weekend and rebuild every 8 hours.  It’s the same carb as on the X30 and I’ve heard a few people bitch about the carb jetting with respect to that motor.  The jetting definitely is touchier than on a Leopard, which was my main motor before the X125, but not nearly as bad as the old mod honda shifter I used to run.  I found a sweet spot and now that I have it, the jetting really doesn’t seem to change much with air density.


      These observations are for the “masters” X125t with the Tryton 27mm, not the “senior” one with the Tilitson 23mm (same as a Leopard).  I doubt the Tilitson “floods.”  It sure never did in 4 years of running a Leopard.

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