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Rotax 125cc

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Max race-spec

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Latest Activity: Apr 12

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Kart Max Jetting: iPhone App (Android too in a few days!).

Started by Akura. Last reply by Ross Tait Apr 7. 6 Replies 0 Likes

Hello,I write you because this info could be useful to some of your readers.Feel free to delete this thread if you choose it, but thank you for reading it and for your time.With Kart Max Jetting, now…Continue

Tags: uranus, software, jetting, kart, max

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Comment by Ross Tait on April 12, 2012 at 19:48: Simply from what you are saying it is driver style and how the throttle is applied/used as it effects the way the carb fuels,tuning etc.

Needles,jetting etc never suits every driver as we never drive(style),accelerate,brake the same. Hope that helps

Comment by Colin Lewis on April 7, 2012 at 8:11: I have a driver style question regarding Rotax (I think)

Yesterday on a practice day. I set my kart up and got the tuning to really hum. Ran several stints in it and it was crisp and reactive.

My daughter who was also running her kart always seems to have a miss around the 12000rpm mark in her kart unless we run it up to 3 jets higher than mine. This miss isn't the big pop that happens if lean. We have identical carb settings.

Now the question arises when she jumped into my kart and ran it for about 20 laps. The miss that she suffers reproduce itself in my kart. The air density, weather and other variables had not changed.

Why does she suffer from this miss in karts that are otherwise performing?

Any ideas welcome.

Colin

Comment by Gavin Bright on May 25, 2010 at 9:53: Hi All Just added a file regarding setting up the Senior Max Power Valve, hopefully will be of help

Comment by Gavin Bright on May 25, 2010 at 9:50: EXHAUST POWER VALVE INSTALLATION GUIDE.pdf

Comment by Ross Tait on May 7, 2010 at 7:37: Check the inlet needle as well as they can leak and make the carb over fuel.
Alot can come down to driver style on the throttle.Squeeze it like it has a orange under it as they are over carbed.If you run richer you will get stronger mid range.
How the carb is setup makes a differance in how the inserts are positioned as well and some have not been done very well.

Comment by Mark Dixon on May 6, 2010 at 22:58: I run a rotax heavy and struggle to understand why I only need to use two jet combinations with a K54 needle. That is a 158 or 160. I'm not complaining but others come to me at meetings and are really suprised at what I use. If I run anything richer it just doesn't run as well. I'm not sure of the terminology but it's a 8mm carb with 3.5 floats(?) and second clip? Essentially what I'm asking is why is there such a variation between engines and settings in a homologated world

Comment by Colin Lewis on February 16, 2010 at 20:45: Good advise with the sensors and batteries. I once had my Senior get upto about 76-78 degrees. It didn't miss or pop but next race I increased a jet size and everything was good again, temps came down and performance was still good. Having said this the senior eng seems to run a lot hotter than my daughters Jnr Rotax. Food for thought.

Comment by Ross Tait on February 16, 2010 at 20:30: No worries do the batteries first ,then the sensors.
Oh also check the terminals where the batteries sit as well are good and clean.

Comment by tayler forbes on February 16, 2010 at 20:27: cool ill check the batterie as well

Comment by Ross Tait on February 16, 2010 at 20:18: Welcome and check batteries as well with a digital voltmeter as some are flat or low from new as well.