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.