Where to buy 12 port injector and TXC ECU?

Make sure you reset the tps and adjust the settings using the ibeat system. Glad you found one

It cost slightly more than the original kit cost but I could not find anything else and it was new and unused so I paid it. I installed them both and reset TPS and CO settings. Much better rideability and performance than stock ECU and injector but still has some lurching/jumpiness at low speeds. Even for the TXC I see that different people set the TPS and CO levels differently so I'll do some more playing with iBeat to see about getting it optimized. I'll check the valves too and make sure all is good there. I know it will never have the lugging ability of my Husaberg FE570 but I want it a little bit more friendly to ride for my sons in tight single track. I also went to 12/50 for the sprockets and that helped too.

Follow up to the ECU/injector upgrade: I did some more TPS tuning and got it working well. I used 102.3% WOT, and backed off the butterfly a bit after I set the idle mV. Took the bike out this weekend and tried it on some tight singletrack and hillclimbs. Definitely runs well and no bad behavior at lower rpms. More power everywhere. Stupid to have to completely replace the ECU instead of be able to load new ignition maps but that is how it is. I think the lower gearing helps too for the tight stuff but kills off any real dual sport capability. No good answer there without getting new trans gears machined up but I got it for tight stuff. Now I need to get the suspension set up properly.

I cured those issues by selling it for a FE501...

I get that and it makes sense if you want it to be an all purpose bike. I have a Husaberg FE570 that does everything well enough (except that picking it up is not fun). I got the TE310 for my sons so they can ride singletrack with me and ride from campsites without getting a ticket. I don't think a 310 has enough torque to be a good dual sport anyway but for tight stuff it's a really good machine. Also, the low miles TE310 cost 1/2 the price of a used 501 in CA.

Roger that. My 501 will go deep in the tight stuff but I prefer my 300 for the knar. I'm spoiled enough to have both. Hehe