air inlet on lt50 blowing out

[JOHNCOLLINS]

hi guys, i am a complete newbie so here goes.
my kids have an 1995 lt50 that ticks over but no power.
i have read all the threads multiple times and learned quite a lot. thanks guys.
i know this thread is similar to other threads but i think mine is different,
however i still cant get our quad to run good.
looking on how to derestrict on this forum i decided to give it a go thinking i will get more power.
it seems that whoever had it before us, they tried to derestrict it but did not do it properly,
there was no restricter in the exhaust, or none in the carb,
there was one between carb and cylinder, so i removed this,
also i removed the first (lowest) pilot jet. also i cleaned the other pilot jet,
it idles perfect but with my hand on brake, when i throttle it about 50% it starts losing power.
if i lift the back wheels off the ground and then throttle it, it revs up really quick and sounds perfect at full throttle.
there is definately a difference in speed of revs since removing pilot jet and the washer but still no power with anyone sitting on it.
also there was no air filter with the bike, just the plastic round cover attached to the bike.
i have noticed if i hold my hand over the hole the air is blowing out of the carb and not being sucked into it.
from my very limited knowledge of all things mechanical i know this is wrong (i think, lol)
also what air filter does it take, will i get a suzuki one or a universal one?
from other threads i have also checked the spark plug, it looks new, when i removed it it was a little black but it was not wet or sooty.
the spark plug is a ngk bp4hs, is this the right one?
also in the oil resevoir in the clutch cover, does it take clutch fluid or gear oil, (i told you i was a complete novice, lol) as it looks a little low.
i hope this is enough info, and please have patience with me for posting yet another post about the lt50.
thanks in advance

[JOHNCOLLINS]

hi i found the problem with the lt50 having no power.
i put an old towel over end of exhaust and it made no difference, so i thought there is a problem in exhaust area.
there is a nut under the box on the exhaust, i removed this and WOW the difference is amazing,
it is flying now