The fuel I use is 100 octane OMV gasoline, the oil is motul gp and I put 40 grams per liter. I never had any problems with my old 10c before
I’d like to try a U12 needle because I’ve never tried one. I always ran the k98 along with the DQ
You should at least have the needle in 4th position, compared to a K23 this needle is very lean. Orange is your setup, and blue same but with K23
L’altitudine alla quale guido è di 200 m. Quindi per te è meglio provare k23
I’d be interested to see a visual representation of what you are describing, it sounds interesting.
Very good point re: the use of high octane race fuel. In Europe, at Regional level, people mostly use 98 (93 US) octane pump fuel, which may contain ethanol and is less stable, leading to an easier time in detonating like the picture we are discussing, which to me is indicative of off-throttle detonation due to not enough fuel being supplied.
In terms of piston reading, i’ve always been taught that the more the deposits move towards the center of the piston, the leaner the condition is at WOT. Ideally, you would want a slight caramel coloring at the center, which indicated you are close to the limit.
I think picture here bellow is pretty much the quintessential " Finals" carburation, whereby you are beginning to detonate at low speed / off throttle for the cleanest possible pickup all the while being also on the limit at WOT, with very clean combustion that doesn’t leave a lot of residue. Not sustainable for the life of the piston, but to extract maximum performance at that point in time.
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You mean 40cc correct? Not grams
Your temps are ok I don’t see an issue.
Check float height
Check advance
Check squish
If it’s all good, try K23. If still a problem, change fuel.
Also, next time you warm up, keep engine stable @ low rpm and have somebody spray WD40 around intake, base of cylinder, vacuum port, crank and see if something changes (air leak)
Is your app data for the R2 specifically?
If yes, please send link for the app.
All the tm engines up to R1. But is applicable on R2 as well
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Simone- I didn’t intend for such a delayed reply, but I happened to see a piston that came out of one of my engines that fit the description I was referring to. Here are some photos. Minor detonation on both intake and exhaust side. There look to be some markings on the exhaust side caused by some sort of debris, but I don’t believe that accounts for all of the detonation.
I use that app primarily for looking at relative difference between settings. I find the best performing jetting for me to show as rich on the idle end and lean on wide open throttle.
The only thing I use my vortex jetting app for anymore is to look at the relative elevation 
Yeah!
I have the same experiences
The app worked great for me, Kz now sold 
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Things that are of interest here :
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What oil do you use and how many hours on the piston ? I ask as it has coloured a lot. This can either be due to a. a lot of hours or b. an oil that leaves a lot of residue from the get go. In EU we have one called Yacco, which lubricates really well but leaves pistons very dirty.
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Have you noticed the slightly assymetrical burn pattern, mainly vissible with the skewed center burn point to the right ? It would be interesting to know why this is happening and if it has anything to do with the transfers in any way (Maybe one opening half a degree earlier for instance)
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The way i read the overall condition is indeed very lean across the entire range, further justified by the withening of the upper most crust of the deposits. Do you remeber what carburation you were running ?
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@Simone_Perego Happy to share:
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I run Elf HTX 909, as it’s what the main series mandate here in the US. I’m not sure if you have 909 over in Europe, but I believe it’s a higher castor content vs. HTX 976. This was mixed at 5.3%, and the piston/ring pictured has 2.25 hours of (on-track) time, including break-in. We run either VP MS98L or VP C12, both of which are leaded. I don’t recall which fuel this was in particular, but they color a piston very similarly, and jet within a couple sizes of one another.
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I did notice the asymmetry, and was curious. This is the only piston I’ve ran with this engine, but it runs quite well. I didn’t make any notes of offset transfer durations, but that doesn’t mean they aren’t…would have to check upon reassembly.
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I’ll share my notes from that day. This is different than what I had typically ran on my previous R1, so a bit of experimentation going on. Ultimately I don’t believe I was too far off for the jetting in the final, but my notes reflect a sentiment that I could have gone leaner on the main jet. This is relative to other EGT data where the engine had performed well.
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Bonus to the above, here is my onboard video from that last race. Unfortunately my clutch cable came loose before the start, so I did a rolling start with the TAGs behind the shifter grid 
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Ok, you run literally the best oil someone could ask for and the piston is fresh. I had indeed completely forgotten the discrepency of the leaded fuel in the US, which is almost certainly the “culprit” in our discussion here.
To further expand on the above, going to 142 with a K22 is “insane” by normal, unleaded 93 octane gas, which is what we run here. Even with a spec Panta 102 octanes, i would never go that low under any circumstances as the engine would grenade in like 2 laps ( you wouldn’t even leave the paddock tbh, as it would sound demented on the trolley lmao)
It sucks as this further complicates our discussions as i have 0 knolwedge of carburating with a leaded fuel…
Interesting that you alter emulsifier and pilot jet to these degrees too. I’ve personally always have stuck with 60 outer, with varying degrees of inner emulsifier chiefly between B47 to B52. I’ve only strayed far from this when using U series needles.
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I do believe it’s the fuel that creates the apples/oranges scenario here.
Running main jets in the 140’s is pretty common with our weather and our fuel. Pilot combo selection depends a bit on the track and driveability. NCMP is pretty “point and shoot”, even in the alternate configuration we ran that weekend. Going richer on the pilot circuit definitely allows for a leaner main. With the R1 I’m typically in the 60-65 range on both inner and outer. I pretty much never go below a 60/B60 ever. Having tested many pilot combos from 60/B60 all the way to 70/CD1, I found that single-point increments make little to no difference, and thus adjust in 5pt increments most of the time.
I don’t have as much experience with the R2 yet, but my findings are such at it requires more fuel on the pilot circuit and needle vs. the R1. I don’t run the K22 with the R2, and only in warmer weather with the R1.
If you think 142 is small, you’d love my main jet selection with the K93 
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I do echo that the R2 runs slightly riccher as a broadstroke rule vs the R1, and this is mainly down to the exhaust system vs the R1. Granted it will not disintegrate if you run it with an R1 carb, but it will not work as well.
Altough i would have guessed lead would have an impact on the way you approach carburation, i never thought it would have been to this degree. Quite peculiar that you run miles leaner on the main jet than us, but much richer on the pilot system.
I can only imagine the 115 main with the K93 
I am running Sunoco 112 with elf 909 mixed one bottle of oil to 5 gallons. I think that’s around 19:1 or something like that for the ratio.
My engines is TM R2 Total black with a power airbox. I am in the low mid 150’s on the main, and 60 on both idle jets. Engine takes throttle nicely and has a usable rev range of 9500 to About 14,700 RPM. Egt’s in the low 1200’s F
Simone,
with the C12 in the US you can run way leaner than us in EU - I remember my Modena KK1 set up 14 points leaner at GoPro Motorplex than Lonato with same weather conditions.
Also, K22 is a weird needle - k23,k16,k28 and k98 are common ones for TMs.
I remember so many pistons changed when Supernats was running Aspen eco-fuel that official team where running around asking pistons to everyone in the paddock 