I just bought a z400 off a guy. When i test rode it, it was a bit cold natured but i didnt deem it anything to be worried about. I get it home, and bam, it only starts when youre pumping the throttle. Once it does start it will only die as soon as you let off of the throttle, or in other words, it does not idle, at all... it runs fine from mid to top, but low, it just struggles not to die... and like i said, it hardly even wants to start, and it WILL NOT start without being on the throttle

Well i come to find out it had about 6 month old gas in it so i drain that... well i went ahead and the spark plug tonight just to rule that out of the picture... then i took off my gas tank and took out the petcock and there was a decent amount of rust/dirt on it when i removed it i began to tear apart the carb because i have this inclination its the pilot jet... well anyways i go to take off the bowl and i stripped the ******* screws getting it out... so i just stopped while i was ahead, put it back together to see if the spark plug would make a difference... and of course it didnt.

SO i need help diagnosing my starting/idling problem and also any tips or tricks on how to remove the 2 stripped screws on my carb bowl

 

Use a dremel with a cutting wheel on it and cut a slot in the top of the screw....not too deep, then use a flat head screwdriver to get it out. You may be able to do it with a hacksaw. If you have to just cut the head of the screw off completely.
When it happened to me I bought a very cheap (like 5 bucks) "dremel like" tool at Harbor Freight that came with bits and used that. I've since bought a real cordless Dremel that is very handy.
Once you get them out replace them with allen head bolts. While you are at it replace the screw on the carb boot clamps with allen head bolts. They will all take the same wrench. I bought a cheap T-handle allen set at Harbor Freight that works very well for those bolts/screws.

I would think once you get into the carb you will solve your issue.

Is the plug for the fuel screw still in?

 

no that plug was gone... i believe someone had rejetted it before


Ok well I actually figured out the dremel trick on my own and got em out. I cleaned the carb out and my pilot screw (what I felt would be my culprit) and it had some build up and corrosion on the spring. I got it all back together and took about 15 minutes just to get it started but once it started I kept on the throttle and warmed it up, reset my idle and took it around the block an came back and to my amazement it's idling and not dying!!! But the only thing, when I go to start it I still have to give it some gas to start it, you know what may cause this?

butttt then i get home after work about an hour ago, and were back to square one... not starting at all... what could it be my valves?

 

Probably need to clean it out a little better. Also you may want to check the fuel screw to see that the tip isn't broken off in the carb (bad news if it is). Gently tighten it to see how many turns it is set at before removing it. Most likely it is 2.25-3 turns out depending on your mods.

As for not starting it very well could be a valve issue. You may want to check the valve lash to make sure they are in spec. If your intake valves are too tight it will not start.
See if it will pull/push start. That's usually a pretty good indicator on the valves. If it starts by pulling and starts when hot, probably the valves.

 

very true about the valves on my sons Z we try to keep valves adjusted but still at times can take a while to start but I just installed a edelbrock performance carb and what a difference it makes starting it all we need to do is pump it like 4 times cold and it fires right up and idles.