Thank you for the insight Andy
I like the concept that the fuel mixture can be adjusted from the steering wheel
yes, keep in mind it’s emergency only and you should only go few clicks (I tried max 3 so maybe a 20% restriction, my guess), the carb is not supposed to work that way so you are forcing things…past that it starts flooding badly on throttle opening…it will save your day but not improve performance at all, it’s a quick patch that I think helps those who like to run super lean and throughout the race they realize they are in trouble or they may want to give it a click for peace of mind. Hope it helps!
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I wonder, might it be possible to jet in the “middle ground” & use the dial to give you a small workable range?
It would be interesting to test, although I’m a little skeptical as this is a crude way to adjust it…you would have to intentionally set it extra lean and then restrict one or two clicks to compensate and see how it compares to a well jetted carb that is working as designed. Interesting for sure!
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Yes, agree. Definitely would go conservative on the lean jetting, but if the dial allows for a workable, usable range, it would be an improvement over dedicated static settings.
What I’ve observed from few tests (gradually close and see what happens, run it half close for few laps, fully close it and see what happens) is that the max circuit seems to be working OK. Meaning, closing the tap makes it richer but jet/tube/needle work pretty much as intended. However, the low circuit (idle jet/emulsioner) seem to work progressively worse: engine would progressively lose ability to pick up revs, to the point that after the main straight, it would bog down really badly coming off the first turn. You can notice from 4th click onwards, past half turn on the tap it was pretty much hopeless.
On the other hand, it helped me with jetting…first time I tried this particular engine, I thought I set it on the rich side for break-in but I was still lean. I had my suspicion during first couple of laps, so I closed the tap a couple of clicks on the main straight and the engine started pulling much stronger…instant feedback
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I had one of the valves on my old kart with my Rok shifter. One other use is if your fuel pump gets weak mid race you can close it to keep the carb fed. I had this happen on my Rok prior to installing the valve and had to pinch my return line whenever I could to keep it from running out of fuel.
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Killer build thread thanks for going so in depth!
For the paddles: Is it an ease of use thing? It’s just badass so I did it? Are they allowed in most series/classes?
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Medical issues. It’s either paddle or nothing, I can’t really drive a lever for more than a couple of laps because of pain and risk of throwing my shoulder out. With it, I always have the better shoulder helping the weak one. I believe most series allow it, as long as you get authorization ahead with justification/papers and only if you don’t have the ignition cutoff. Without cutoff, there is no real advantage other than fatigue/helping people with issues or even disabilities.
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There are some cable operated systems out there that are completely legal, but you don’t see them often.
I’ve looked into those, been told they are very finicky due to cables stretching. But I haven’t tried them. In the meantime, Seven came up with a new model that seems to be well designed, I’d be curious to try it out and compare. 500EUR price tag is a little steep for what it is though.
TheLab also sells the Motori 7 mechanical cable setup alongside its in-house D Shifter units, but it’s a pull cable design, so the lines stretch & thus require a replacement schedule, & they’re custom made for that unit. A design incorporating a push-pull cable would not need replacement. Just saying.
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I thought the paddle shifting system from Motori 7 is only good for Motori 7 engines.
I have paddle shifting on my KZ, made it myself, works perfectly, with cut-off, no need to lift the foot.
Supposed to be GTG for most all KZ motors. I’m just not a fan of the thin pull cables. A well oiled push-pull cable would make life simpler for the owner. There’s always a reliability rub with new products. Trying to maintain positive cash flow stream, I guess.
So that’s a rotary actuator vs linear?
(Not sure if rotary is the correct term)
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Interesting…both the Mechatron and TheLab (which I think it’s the best) units use a planetary gearbox, yours seems to be direct.
The only “linear” or solenoid-type is ProShift, which I don’t think can work on a kart. I tried (hard) to make it work, but there are issues on a kart that prevent its use, not a fault of the system itself, which I believe works great in bikes, cars etc
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I do have a gearbox, just like the Mechatron which is 36mm, mine is 42mm.
The problem with the Mechatron is that it’s impossible to program perfectly, so stays activated a bit too long and that gearbox will stop working, but you can buy the gearbox from Alibaba for very little money, around $15, or you can cushion the connecting rod with springs and then it will last a long time.
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