I've had the carbs off the Gpz for a clean a couple of times lately as it still wouldn't run properly. I needed an airline to blow through the carbs but I haven't got one so I came up with this contraptionClick to view attachment
I found a cork that fits tightly in the neck of a coke bottle and I drilled a hole through it to pass a length of windscreen washer tubing through. I cut the pipe into three pieces and fitted a T piece(also meant for windscreen washers) onto the pipe coming from the bottle. I ran one length of pipe from the T to a foot pump and on the other side of the T I fitted a short length of pipe. The needle inflator used for blowing up footballs made a good nozzle and lets me get in tight spots.
I didn't know how much pressure the bottle could take so I tested it by pumping in air until it shot the cork out which turned out to be 28 pumps.I drilled a hole though the cap and screwed it in place to keep the cork in the bottle.
I now knew that 28 pumps was safe so I kinked the pipe with the nozzle and pumped up the bottle. Insert the needle into the airway and unkink the pipe. You get a pretty strong flow of air for a few seconds. I took the nozzle off as the pipe was a perfect fit for the pilot jet and tried blowing through and it was ok on three carbs but on the final one it was blocked. I took the jet out and put it in some meths and gave it a good shake around and blew through it with the nozzle. I put the carbs back together and it runs better than ever now.

Very neat



Now you can add some fins and a nosecone, half fill the bottle with water & you can have fun with a rocket too.



Like this http://www.youtube.com/watch?v=20QvsHZw5WM

I work for a kids charity and already play with water rockets with the kids at work. My best version so far has a simple inverted T shaped frame with a section of pipe screwed to it that's slightly wider than the bottle and about a foot long. I've cut open the sides, so that you can see the air being pumped in, and made a simple release mechanism. The bottles will fire anyway once you've pumped enough air in but to increase the pressure and for them to fire on command,10,9,8 etc, I cut a u shaped piece of plastic which is fixed onto the frame and can move backwards and fowards. There's a slight rim on the neck off the bottles and the piece of plastic sits above it and traps the bottle, the cork is kept in place by the base of the frame.
As the kids have various disabilities I've a version with a foot pump, that you use as normal, and another where I've used an old 12 volt tyre compressor that's switch operated. I get the kids to start pumping in the air and I mentally count down to the point that I know the bottle would fire at and then get the kids to do a countdown from 10. There's a 10 foot length of braided wire connected to the release mechanism and when they pull it the bottle is released.
As a craft activity the kids make a small slip on nose cone with fins, out of card, and this is put on the rocket just before launch.
The kids have the choice of a rocket with a parachute or without. The parchute is made of a carrier bag that has string tied to the handles which are duct taped onto the rocket. You drape the bag over the rocket and when it's fired it stays in place until it reaches it's maximum height, about 80+ feet, and then as the bottle drops away it opens.
The parachute serves two purposes-it makes it more fun and it slows down the bottle and makes it easier to see when it's coming down. Without the parachute or fins the bottle drops flat and doesn't hurt if it hits you. If you add fins they drop like a stone and could hurt if they land on you.

nice piece of , kit their , i must build one , you might be able to get a steel air bottle ( cheap ) that paintballers use , as most are going onto fibre or ali ones , you can get a remote line with them , with a on/off .
just a thought , as it might be easier for you than carrying a battery etc around ?? . you might even be able to get it for free , as your doing charity work ?? sure some of the paintball forums might be able to help you out ????

Great minds think alike. I was given a steel dive bottle a while ago but I haven't got a regulator for it yet. I've got a buddy bottle as well which I'll probably end up using.