idl1975

I purchased my TY a few weeks ago and had the identical problem. Would fire first or second kick with full choke, but then die in about 30 seconds, would not accept any throttle. After spending 30 minutes kicking (good exercise) to finally get it running, and deciding it was a poor form of entertainment, I replaced valve float needle and holder (JK Hirst has these) and main jet, disassembled and cleaned the carb. Checked my hoses and none blocked (nasty looking though!). The other thing I did was to simply put the mixture screw back to the factory setting (having got a .pdf of the workshop manual) - fully in and then back out 1 and 3/4 turns. Starting it on those settings it revved like a ******* and I had to adjust it out bring the idle down. I'm used to modern CVs and four strokes where the idle speed adjuster actually does something, but it seems on these stone age items fiddling with the mixture screw is critical. Now, since then, I've had no further problems with starting. If you've taken the carb apart and cleaned it already, maybe also check your mixture setting? I just noticed that you didn't specify that you'd tried adjusting it.