2 stroke black plug

[770]

So today i mixed about 7 liters of gasoline and about 1,5-1,8 dl of oil in the tank. (2% mixture is recommended) I ran it for a while and after riding at high rpms at the highway it suddently stopped. When starting the engine again it would not idle but it ran if I gave it a little throttle. There was also this really scratching sound coming from the engine. I checked the plug and it black as hell. Was the oil mixture too much? And why is the engine making this scary noise?

husqvarna 125

[mentalboy]

[770]

7 days ago was the last time I checked it. I think it was also running too rich since in the lower gears it sometimes had problems hitting the powerband. So for example in second gear when it couldnt reach the powerband I shifted up to third and then it hit the powerband.

[mentalboy]

And one can assume that the plug was a nice light brown colour beforehand?
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Make mine a Corona.

[770]

Yes, this was how it looked with a 154 nozzle:
https://postimg.org/image/9hzfxion7/ Dellorto 28mm

After that I changed to a 156 nozzle.

[mentalboy]

Nozzle? Would that be a jet perchance? (which part of the world do you hail from?)
Why did you rejet? I think we could do with some background on the additions/alterations you've made
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Make mine a Corona.

[-]

2% is 50:1! Maybe OK for motocross with short bursts of throttle but far too lean for prolonged high speed highway use. I run my TZR250 race bike on 33:1, about 168ml oil to only 5 litres of petrol. The longest flat out straight it has to deal with at that level is the back straight at Snetterton race circuit.

I suspect you had a partial seizure due to lack of oil rather than lean mixture. It can still be running rich on petrol/air and seize from lack of oil.
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TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.