Scooter running too hot!

[lassestyle]

Hello. I recently started doing a little bit of tuning to my carb and it was running fine for a while. Then I switched to slightly less oil:fuel ratio, where I had about 30:1 before and have about 40-45:1 now. It's hard to really do the calculations cus I was unsure of the mix I had in the tank before I put the new mix of fuel in. I also raised the needle clip one time so it's at the top, because it was chopping a little bit in the middle and it usually worked to raise the clip one notch. I also upped the pilot jet two sizes from 38 to 40, and did a little mixture screw tuning. I also recently installed a manual fuel petcock, and plugged the vacuum line with a bolt, but I don't know if that has anything to do with it.

Now it's started running really hot. I run a 70cc kit with a 21mm carb with a sport filter. I've upgraded from a 90 main jet to a 99, and downgraded my pilot from 45 to 40. It also has a power jet in the float bowl, that I've yet to check because I've never seen it or used it before. Maybe that has something to do with it running weirdly in the 1/2 throttle position? I recently took a little short ride of about 2 km, and I didn't really hold max throttle for a long time. About 10-15 seconds of the whole ride. Other than that I ran with 1/3 throttle most of the time and 1/2 throttle a few times to test if the chopping would go away if I get more up to speed. I also only ran about 60kmh the whole ride, and it hasn't really ran fast in the time that I've had it. I did upgrade to a performance variator and I currently have 6g rollers in it, and a stiff clutch spring on an old OEM clutch kit. When I went home from the little short ride, and I stopped the engine but turned the ignition on again, I saw that my little multimeter had a reading of 125 degrees celcius on the cylinder head!! I was very shocked as the moped doesn't really reach high RPM's and it gets around 5-6k and 8,5-9k with full throttle. Can someone please help?

[90GTVert]

125C or 257F CHT can easily happen at part throttle. I would guess that went up when you changed the needle clip position.

You may want to monitor the CHT while you ride, if possible safely. It would help to mark your throttle in at least 1/4 throttle increments so you can see exactly where it gets hot.

[lassestyle]

Thanks! Do you have any tips on what I could do to make it not chop in the 1/2 throttle zone? If I keep raising the needle clip, it'll just run leaner and hotter, and I don't want that on a (basically) brand new cylinder kit.

I've been thinking of taking off the cylinder and trying to port it a tiny bit and file those little walls at the bottom down so they are very pointy (Sorry I'm from Denmark and I don't know the English terms for the cylinder work). Also, would it be worth it to look into shimming? I'm gonna get a new clutch but keep the OEM torque plates, since they're ZX and are supposedly way better than most other plates. Im running a pretty wide belt, and since I don't really get much top speed, I think I should go a little bit slimmer and still shim it a little bit. But wouldn't too many shims cause the Kickstarter to always grab the starter wheel?

Also, how scared should I realistically be of my cylinder kit seizing up? I've seen many videos from Mopboyz, and every time he installs a new Polini Corsa cylinder kit, he usually goes wide open not long after. And when he built the Honda Dio 120cc stroker he also went wide open not long after. I've been extremely concerned, even though I have a brand new kit laying around. I'm pretty new to bigger cylinders as I didn't have a two stroke until 6 months ago. Thanks in advance!

(Edit): Isn't a healthy operating temperature for a 70cc kit around the 70-90 degrees Celcius? I don't really have much info on the kit as I bought it from an extremely unknown brand, and they only state the piston pin size and bore size. I've also been thinking about properly doing squish, but in my opinion I think it's pretty hard even though I've never done it, and the last time I tried to measure my cylinder squish it was on 0.3mm and from what I've read, thats a bit tight 😅. What should it be laying around on a 70cc kit? And what torque should I tighten the cylinder with after?