Suzuki 2 Strokes

Guys, my T500 consistently fails to start. The engine was rebuilt having had a re-bore (re-bore +1mm), and new pistons (from a GT750), and the crankshaft overhauled (by FirefoX) including new rods and seals etc. New coils have been fitted as well as new points and condensers. All of the ignition circuit wiring checked for shorts and breaks. Timing checked both statically and dynamically. the carbs have been stripped and cleaned, new jets fitted (Pilot, Main and needle jet), float height checked and re-checked. Mixture is spot on and my plugs could be used as a demonstration of what a perfect mixture looks like. When on those rare occasions that the bike starts, it runs and rides very well although appears to suffer with piston slap at tick over, and a degree of deceleration surge (see my other post). But when I try to restart it (regardless of time stopped - half an hour or over night etc) it will not start. On removing the plugs, they appear dry and will spark, it appears that the engine fails to suck any fuel in. If I spray a little fuel into the carb inlet the bike will start I have removed the carbs again and checked the inlet suction which does exist but it blows as much as sucks. So what should I expect ? I am beginning to think that the "GT750" pistons are not suitable for the 500 - any suggestions guys, many thanks

Hi Ken, welcome to the forum. You'll notice that I've changed your username to kenintheuk as it's not good to put a personal email as your user name! Your password and log in details are otherwise unchanged.
The T500 pistons and GT750 pistons are the same, of course they have to be installed correctly to work properly!! Although you do say that when it runs, it's ok.
Possible causes for bad starting are poor spark at the plugs or blocked pilot jets in the carbs, so that's where you need to start (no pun intended!)
Which bit of the UK are you in? There may be someone local that can pop in and help.

From your email reply, the fuel level in the carbs may be a tad low. I'll send you a service manual with details.

Check that the carb slides are not switched. The cutouts should face the air filters.

The starter jets are in the bottom of the float bowls. Use a flashlight to confirm that they are clear.
Use a spray can of carb cleaner to confirm that the various carb circuits are clear.

What is the history of the bike?
Some years ago I bought a GT380 with a petcock so packed with crud that it barely flowed any fuel. Might you have a similar problem?

Guys thanks for the help and suggestions. I appear to have resolved the starting issue but now I have a heavy rattle/knocking at tick over. For completeness and should anyone else experience a similar problem. What I had done (embarrassingly) is in removing the throttle cable slack to synchronize the carbs and ensuring the oil pump stroked in proportion to throttle. I had lifted the throttle valves and created a gap under the slides. I realized that the carbs require a vacuum for the "choke" to work and the pilot/starter circuit. Once I had set the slides up correctly, the bike started. Many thanks again guys