i just got the vertex clip ons, i cant seem to remove the bar end from the oem clip on, and even if i can remove it how can i install the bar end and the grip, because there is no holes for the screw to go threw on the vertx clipons.
And you won't be able to use the barends, the clip-ons bars should come with a little plastic plug for them. Well, the only way you might get them to work is to get a expanding type mount, like CRG has for their bar-end mirrors that you could fanagle in there and mount your bar-ends to, but really, why do you want them?
clean them of all the lithium grease, or whatever you used, and then get some Dawn, or other super slippery dish soap (the bigger the bubbles you can blow with it, the better), mix up a little in a cup (1-2 in 8 oz of water), lather the inside of the grip with it, slide it on, and don't touch it for about 20 minutes. When you come back, it should be rock solid on your handlebar....
Something else I've tried that works well too is paint. Get a gloss (not sure if it should be lacquer or enamel, I've used both without issue but the lacquer may eat the rubber?) paint, I used black, spray the inside of it and slide it on. You'll get some coming back out, so grab a rag and clean it up before it dries.
The wet paint allows the grip to slide on, but as soon as it dries (don't keep twisting it, just as Spooph said get it on then leave it for a bit) you can't twist them things off. I did that with my clip ons for the Ninja and my quads over the years, never been able to pull a grip after that.