strange rare problem....

Ok so at the end of last year I built this new motorised bike. I was planing on making it, getting it running good and then fully moding it. So I went on eBay and ordered the kit and then went and got a bike. Took me like 3 weeks to build it cause I didn't get much time to spend on it. Anyways so Im about to go on the maiden run, I put in the correct fuel/oil mix (16:1) and use Good oil(unlike last time) I do everything right and go to start it and it pops and fires first go. Except as soon as it starts it just revs up. And up. Also I had to put the choke on to get it started,anyways I could never figure out the problem and I took it to various diffreert people and one of them loosens all the cable s and sad there u go fixed it but he didn't also another good mate of mine had one look at it and said that it was an air leak around the Carrie to intake manifold,so we put some temporary tape around there and I started it and it ran fine. Put it away and came out the next day and it had the same old problem just revs up and if you take the choke off it dies down and shuts off also if you try to ride it it just loses power and jolts along till it stops.so confused and would appreciate some help please also now its quite hard to start ( takes a while) air leak, fuel mixture ,.????

air leak

Or really poor fuel flow...
Clogged fuel filer, crimped line, poor carb angle, poor tank placement, etc.

Ever left your bike running at idle and shut off the fuel?
We make a habit of it here before we bring them in the shop.

As the fuel level in the bowl falls you start getting a little extra air in the mix thru the jet which makes the engine rev up just before it dies from total fuel starvation.

A small flow would be just enough to keep it wanting to go, but not enough to keep it going.

Ok so what should I try,no fuel filter???

turn on the petcock, wait 5 minutes, start the bike and ride it.
If the problem exists right away then it is an air leak.
If the problem happens later then it is a fuel flow problem. (replace the fuel line filter and remove the petcock and clean off its filter and clean out the gas tank)