u/Powerful-Fudge-3535

I have a Suzuki TSR 125 from 1993 that has 18,000 km and that I haven't been able to ride mostly because I wasn't with it but also because it's having problems.

As I said in the title it won't idle even though I completely clean the Jets of the carburetor.

I tried a different spark plug from my rieju mrt 50 sm from 2022 which has the same model spark plug but it still had the exact same problems.

It also won't rev past 6000 RPM and sounds horrible when I'm in neutral. Video attached of me trying to. Doesn't work in gear either.

Previously, I had a problem with the valve seat o-ring not sealing so it would flood and I was able to fix that and then this popped up which was hidden behind the fouling spark plugs.

Could be maybe the stator or the CDI I'm not sure exactly what could cause this.

Here is a link to someone driving the bike to know what it sounds like normally: https://www.youtube.com/watch?v=MiLdA6IqFwE

And him reving it in neutral: https://www.youtube.com/watch?v=yP8dM79xYWI

Also, i don't have a tool to measure compression, i have a multimeter, I have tools to change things myself which is what I want and will probably do.

Edit: the engine has a power valve that is supposed to open at 6k, if that has anything to do with it. Since the bike was flooding, I'm sure it's full of carbon as well, maybe the power valve is too.

So I have a suzuki ts125r 93' (sf15a) that's been giving me lots of trouble. The story:

Last year I got it running great, kinda, clean all the way to 10k RPM no problem. Then the float needle valve O-ring failed and it started flooding. Spark plug fouled from that, replaced the plug but it kept having issues with fouling. Eventually it wouldn't rev past 4k RPM and then just stopped working altogether from flooding/fouling again.

This year I finally replaced the O-ring, no more flooding, bike runs again. But now:

Idle:

Won't idle at all without choke
With choke it barely survives
Without choke it just dies, need to keep giving it throttle
Idle screw is all the way in, mixture screw at ~1.5 turns out (tried a bunch of combos, nothing helped)

Top end:

Full throttle actually pulls clean and smooth
But it won't go past 6k RPM, the limit feels like when you hold the throttle at a certain point and it cant go above that on two strokes, but i am going full throttle while driving and accelerates but when it reaches 6k all of a sudden loss of acceleration because it's stuck there. (was 4k last year, was 10k originally)
Also heard a weird poof from the exhaust a couple times (which doesn't/never hapens), like a misfire or gas exploding in the exhaust, not sure.

What I've tried:

New spark plug (didn't help, same exact issues)
Cleaned the old plug, tested spark against the casing while spinning the engine, spark is there, looks fine
Tried multiple idle mixture screw settings
Cleaned the pilot jet as best I could but the passage is miniscule and I couldn't fully get in there
Main jet might not be fully clean either, but could possibly be fine
Tried a plug from my 50cc (same type, runs fine on that) — same result on the 125

Haven't checked for air leaks, CDI, compression, or reed valves yet. Any ideas what's going on?

Suzuki tsr 125 93' not revving past 6k and doesn't idle.

1993 Suzuki TS125R 2-stroke won't idle and lost top end RPM, help, (suzuki ts125r 93' sf15a)