NITROUS OXIDE ( nos / n2o ) advice forum

As the weather is warm I thaught I go and put my bike to the test today using the nitrous upto 100% which I haven't yet done. Wow the warm weather really gives the nitrous some kick. Emptied to bottles in under 2 mins lol. Came home and refilled. Went out again. After another empty bottle the bike started to act strange when I come of the nos. I used it couple times again at lower power and it was still acting strange. Came home and decided to check plugs. This is not a quick job on my bike . Steering damper off , steering head nut off, mirror stay moved, seat off. Tank up with 4 more bolts. Airfilter housing off and then the plugs. Anyway the tip on one plug has gone. Completely melted. Other 3 are ok. They are all a tan to brown tip and light tan around the base of plugs.
Worried about my engine I did hot and cold compression checks and engine is a ok.
I'm running 90 nitrous 90 fuel jets. Gravity fed fuel. Using 2 deg retard. Why would it melt?
Also the strange problem is when I'm on the button accelerating when I go off nitrous I can feel pull back a bit but when keeping throttle even the revs die and then lurch and hesitate for about 5 or 6 secs then revs back to where it should be? Any ideas?
Should I be worried and get the nitrous checked. The bike does not play up when nitrous isn't used
I will try and post plug pics . Advice needed. Thanks

I just been out to try it with new one up heat rated plugs. As I thought the bike runs like shit with them in. They foul up with fuel and make the bike cough and splutter so I can't use higher plugs. The plug that melted was standard ngk for the bike. And the hesitation and lurch was still there at lower nitrous power (30%). I checked fuel glow and fuel pours out of the tank so it's nothing to do with fuel flow out of the fuel tap.

photos of plugs. notice one has melted http://s1129.photobucket.com/user/djb1309/media/IMG_0237.jpg.html
http://s1129.photobucket.com/user/djb1309/media/IMG_0240.jpg.html?sort=3&o=0 http://s1129.photobucket.com/user/djb1309/media/IMG_0239.jpg.html?sort=3&o=1

They all look way too lean to me !!

A pro set it up so I would of thaught that system should be good. The jets fitted are 90/90. My bike is gravity fed. It ran well in the cold but started playing up today and melted plug today. It was 18 c so not huge pressure . Maybe 700 psi. I was really lucky it didn't knacker my engine.

How was the jet ratio determined, as it's HIGHLY UNLIKELY that it should be 1:1 on gravity fed fuel? Please send me the answer by email (trev@noswizard.com), so I can deal with it as quickly as possible

DON'T use the nitrous again until I give you the go ahead.

There shouldn't be any reason for one grade harder plugs to make the engine run rough NA but if you can't figure out why it is on your bike, the answer is to CUT BACK the ground electrode until the end JUST overlaps the nearest edge of the centre electrode.