Yup, you remember correctly.

Removing the lambda makes little or no difference. I'm presuming that with the lambda, the exhaust fumes are less tough on the enviroment. EU directives have come to bike-land I guess .

Anyway, as I said in the other thread, the only effect I have encountered by removing it, is that it maybe runs 1 km less per liter petrol. I say maybe, because that one liter less may have been caused by my particular riding style that day, headwind, heavy luggage or whatever, and not due to the lambda being disconnected. In any case, the difference is neglegable. Performance wise, the engine thumped happily along as always (and no, my xt660r doesn't "surge" either. With or without the lambda). The engine error light does not come on when you disconnect the lambda. My mechanic claims that he may be able to detect the lambda failure in the computer log, but it realy doesn't make any difference what so ever if he can or not.

As for the catalyst problem; yes, catalysts will be burned due to the extremely high heat you'll expose them to with leaded fuel. The burning of catalysts itself will not impare performance of the bike, generally speaking. This problem is not limited to Yamaha bikes but any bike with a catalyst (or car for that matter). As for the clogging issue, it is still only a theoretical problem and I haven't encountered anyone who has actually experienced it. But as I said in the other forum, I'm not about to do field testing in the middle of Sahara. Going to play it safe and get some catalyst free ones.

By the way, Carbon Can Company should realy get their website running soon, or they'll miss out on my business. 4'th of November is just around the corner (yay!).