Fueling Problem

[RPD]

My 2019 CSC TT250 begins to hesitate and then cuts out at high RPM in 5th. It will stall but then restart after I pull over. Otherwise it starts and runs perfectly.
I’ve cleaned the carb and jets, set the needle to the next richest setting and replaced the main jet with a bigger one but the problem remains. Any ideas would be most appreciated!

[TominMO]

Adjust the valves.

[JerryHawk250]

Originally Posted by TominMO

Adjust the valves.

Yep! That will solve a lot of issues.

[Megadan]

Can you give an exact rpm or is it a bit random.

[alex_in_az]

is your fuel filler cap vent hole plugged?

[RPD]

Originally Posted by Megadan

Can you give an exact rpm or is it a bit random.

Thanks for the question: Above 6000

[RPD]

I tried riding with it cracked but there was no difference.

[RPD]

I adjusted them recently and they’re quiet but I’ll try it again.

[TominMO]

Originally Posted by RPD

I adjusted them recently and they’re quiet but I’ll try it again.

It's not about them being quiet, it's about them being not too tight. Especially the exhaust valve. At minimum you want .06 mm intake and exhaust. Personally I would set exhaust at more like .10 mm.

[Megadan]

Csc states the lash spec as .07mm with a check interval of 2500 miles.

[vividpixel]

Originally Posted by RPD

I adjusted them recently and they’re quiet but I’ll try it again.

I set mine to .06mm and the ticking is very audible only going away at certain RPMs, so quiet on these engines is a bad sign from what I've gathered. Though I've always been paranoid that I did some type of internal damage when I first adjusted on the exhaust stroke, and had to replace a brand new spark plug that somehow grew a much larger gap than it started with. In that case even after proper valve adjustment I had missing at high RPMs until putting yet another NGK in there.