Hello........(help)

[Viirin]

Hello all - I bought my GZ about 9 months ago as a fast and enjoyable method of commuting to college and for those nine months I loved it and it never let me down. It says its a 04' model but I'm pretty sure it's an older, re-registered import. I bought it with 2000 miles on the clock and a story from the dealer that the original owner never used it and it was just sitting outside his apartment until he asked his friend (the dealer) to sell it for him. I looked over the bike but I don't/didn't really know all that much about them so I said I'd take it if he got it serviced as part of the price - it got an "A+" report from the mechanic and so I took it.

About 3 weeks later it stared cutting out on the way to college and so (forgoing a 9am lecture) I pushed it to a local mechanic which wasn't far from where I broke down. He told me I was running it from the reserve tank but he noticed a couple of more things that were wrong with it (he gave it a diagnostic because I had bought my helmet and jacket from him recently). He said that it had:

-had a knock
-a seized choke cable
-out of alignment headlamp...
...and a tendency to wander

"how did he miss all that when he was buying it?" you ask - well, quite simply I'm an idiot

So anyway he gave it a service and fixed up a make-shift choke cable for me because he didn't have a proper one in stock but it was better than having it seized on all the time even though I had to rubber band the clutch to use it, haha

After that it ran like a metronome everyday for the rest of the year, rain or shine...until just recently - there seems to be one reoccurring problem I can't seem to get fixed - I've been in and out to three different mechanics four times so far this summer each one reassuring me that they had fixed the problem this time but ten days later the same problem strikes again and I'm left bouncing around to them like some role-reversed hooker! I work part-time in Domino's pizza so I don't make a lot of money and because of this problem and mechanics that are all to happy to take my money I can't afford my insurance renewal next month! But it's beyond insurance premiums and tax now, I just want to fix this problem so yesterday I went down to my local hardware store and with what little money I had left bought some tools so I can try and fix it myself!

So the symptoms are that the ignition will fire but the engine won't catch and turn over, after a while the engine will fire once or twice (and it sounds like it's off in the distance it's so quite) and then after a good seventy seconds of holding on the ignition it seems to build up some momentum and starts finally ticking over but then one of two things seems to happen: either it seems to loose that momentum it worked so hard to build up and cuts out (over about twenty seconds) or i try to use the throttle or choke to try and prevent scenario one from happening and i flood the engine or something but either way it ends with the engine quite and me frustrated. I tried turning up the idle but it was running way too hot and was at the point where you could drive it without a throttle cable before it would stay running for more than twenty seconds.

The mechanics claimed to have:
-changed the air filter
-stripped and cleaned the carburettor
-changed the oil and filter

I'm going to drain the tank tomorrow and see if the inside is corroded and if it's causing sediment to block up my carburettor and try to clear out the tube that feeds the petrol to the carb but if this isn't the problem I fear I'll be at the mercy of the local mechanics again!

If anyone has encountered this problem before please let me know and if there's any way of fixing it for someone without too much mechanical experience

Any help would be greatly appreciated and sorry for ranting on for so long (I'm a forum virgin)
- Vii