I have a 1996 NSR250 with HRC race conversion. The key card reads "unleaded fuel only" does anyone have any info on why something like 100LL would NOT be good for the motor?

Justin hi,

If you have access to Avgas 100LL use it (Although quite expensive)... It is the best choice you can get for your two stroke engine... Although Avgas is used when things on the consumption chamber are tight... Squish, compression...

If the only mod you have done so far is the HRC card well then is not necessary to go on Avgas... A good unleaded fuel will be ok... If you have started to play hard with the engine then you will have to make several checks on your engine to see if it needs to go on Avgas or not...

Is your bike a track bike or a daily use bike....?

Cheers
Michael

Seems more of a 'leaded fuel is bad mmkay' attempt at deterring the rider from using leaded, rather than a 'warning: leaded fuel will damage your engine'.

I have no idea why it would be bad, and if I knew better I'd say it really doesn't matter and leaded fuel, if anything, would be better for your motor (lubrication + anti-detonation properties of leaded). I, however know better than to advise you that it's use is okay without being better informed myself.

Unless the bike has a catalytic converter, I don't really see the harm. I doubt any two stroke bike would.
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MC21 Honda NSR250. TYGA 300 conversion.

It (Avgas) won't do any damage and may well help the life of components as the lead both lubricates and resists denonation but the ignition curve on the 030 card is optimised for unleaded pump fuel which burns faster than Avgas so an engine designed and setup to run on unleaded pump fuel will make less power on Avgas.
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