Do you have any sensor data to compare? RPM trace will show up as very erratic if it is truly an ignition misfire. If you are running and EGT, you should be able to look at the temps at the time you are feeling the misfire see if there is a significant spike or trough that correlates. Is it bogging, more sputtering or does it sound like its decelerating then smooths when you back off the throttle? If so, could be a fuel delivery issue.
Coming from the car business, I hear customers say “misfire” and have to ask more questions. More often than not the issue is not with the ignition, but something else. Try to describe in as much detail what is happening, how it feels and what the readings form the sensors you are running are correlating to that event.
Sounds like the stator is gone.
We have changed two during our years with X30.
Testing the stator with an ohm meter seems to be difficult.
On one of our broken stators the ohm readings were 127,127 and 122 ohm.
And on the other it was about the same as a new one (222, 222, 217).
So my advice is, change it.
Well, I did not diagnose them, I just replaced them.
The first engine we probably run for a couple of weeks with a “broken” stator.
It seemed like it slowly lost power in the bottom end every time we used it.
But it still was okay in the top-end.
Then suddenly, in a qualification heat of a race, the engine just stopped.
When we got it back to the pit it fired up and sounded okay again.
But in the pre-final of the race it stopped on the first lap and did not start again.
For the final we changed to a new stator and suddenly we got a lot more bottom end and the engine ran just fine.
In the other engine it just died during a race without any noticeable warning.
This was during the Swedish Championships so we just changed the stator and continued to use that engine during the rest of the race.
The week after the race we tried it again at a test.
It was possible to get the engine to start but it started to misfire as soon as you gave the engine some throttle.
Both stators that broke for us were manufactured 2018.
As for my case, I’m new in the karting scene and don’t have any loggers yet. I have a Mychron 2T ariving this week. Water temp & EGT for now. Lamba in the future.
My issue is just like Hakan has explained.
At first it was running fine, but as the session progressed it started sputtering at low rpms and would not rev any more… until the engine died completely and I had trouble firing it up.
I’ll take some readings on the stator also and get back to you guys. It would be great to have a pinned X30 technical section where these information can be stored for future reference.
What kinds of information do you think would be most valuable to you as a relative newcomer to the sport?
I’d definitely like for us to have a more structured and organized way of managing the collective knowledge we have here. Using tags and keywords via search certainly helps, but it’s not quite in the kind of curated summary format that we would all love.
The forum software (Discourse) has the tools and features, including ability to have wiki topics. But it would take a person to curate that kind of knowledge. Really it comes down to people power.
That seems really strange to me given that the stator is basically a four pole magneto (a magnet moving across a coil of wire inducing a current) with one of the poles as a timing reference. I am wondering if IAME changed something in the design from the old white connector style to the new purple connector style. On other side, maybe something else in the circuit is causing a short in the stator. Have either of those engines had other faults or failures? Maybe a poor ground somewhere? Bad grounds tend to overheat circuits and cause all sorts of havoc. Just trying to wrap my head around the cause of the failure.
Is there a fellow racer that might let you borrow their Stator to test. At $200 USD, would be worth it to know before hand if it fixes the issue or not. I think you will find most Karters are willing to help or at least to the point of improving the size of the field. If nothing else, a shop should be able to help troubleshoot the issue for a fee.
On a side note: At one of my early races I was having an issue with my starter relay/solenoid and a fellow racer was kind enough to loan me a spare for the day so I could race. I respectfully returned it at the end of the day and made a personal vow to pay it forward. At the club level, there are not a lot of vendors like you might find at higher levels of competition, but some times a Team or two might be able to help and plenty of folks that have been in your shoes willing to assist where they can.
No other problems with those engines.
Probably vibrations killing them like the starters.
Let´s hope they have changed something in the manufacturing, because we have not had any 2019 models gone bad yet.