Got this old bike for $100. I Have cleaned the carb a couple of times and put new jets in it but cant get it to start. Seems to pass carb cleaner through every hole so I assume its clean.. I pour gas in through the fuel line till I think it's a sufficient amount but it wont hit a lick. Put gas in the plug hole and it fires 1st kick. I can put gas in carb till it runs out the float bowl, as the gasket is bad, and it will crank and run for a sec then stop and wont crank again till I put more gas in till it flows over the bowl again. Weird. Reed valves stuck? A massive air leak? I'm kinda stumped on this. Anyone have any ideas? 

 

Still think go through the carb again as sounds like something has been missed. Float bowl gasket seem to put up with having the bowl off many times unless damaged. Did you remove every jet. The idle mixture jet is very small & the choke jet is a fixed jet in the bowl cavity. Main jet in the side mounting in the bowl gets stuff behind it then sucked up into it from behind--back to front to normal so remove it to check. Needle jet where the slide needle goes is removable using a long 'think' 5mm screw to push it out the top. Jet setter thingy that screws in the bottom of that has an important Oring on it so it seals into the bowl or runs very very rich if leaking. Also there's a brass washer that sits against the needle jet that can be missed or misplaced so don't loose it. Float valve needs to be pretty good to shut off the fuel. Also set the float level somewhere near specifications..
Reed valve won't be the issue, or very unlikely. Could be left side crank seal damaged or blown out but sort the carb first 'i think'. My guess on the information you give. Welcome if you're new & goodluck. Love finding bikes in 'well used' condition that have been parked up far a long time.

Thank you for your response but I honestly have to say I'm a bit confused as to what you are saying. Idle mixture jet? By that do you mean the PILOT jet? I've never heard of a Choke Jet so I'm not sure what you mean there or when you say Needle jet? Are you talking about the float needle "seat" that shuts off fuel income?  By jet setter thingy do you mean the main nozzle? If so then yes that o-ring is new.

My CT2 looked worse than yours when I got mine (for free). Mine had a blown crank seal and a blown main bearing but it still started after I gave the carb a good cleaning (although it ran like crap).

Regarding the carb:
I believe the “idle mixture jet” that RT325 is referring to is the pilot jet (#1 in diagram attached) and it is very tiny. If you look carefully down at the float bowl you can see what I believe RT325 is referring to as the “choke jet” (see attached photo) down inside the small channel and it is fixed whereas it is removeable in other carbs. The carb needs a good soaking in carb cleaner and a good blast with air afterwards but it sounds like you’ve already done that.
Yes, the “Needle jet” he is referring to Yamaha calls the Main Nozzle (#4 in diagram) in which the needle slides up and down. And yes, the critical O ring is also on the Main Nozzle.

Are you feeding gas from the tank (mine was toast)? A bottle? If you want to see it run while you are ordering a float bowl gasket you can use some fuel resistant gasket material (Yamabond?) as a temporary fix. Even regular silicone gasket maker will work for a short time while you are waiting for a new one.

Please forgive me RT325, if I have misquoted you.

Whoops, I forgot the attachments (below).

I was just pushing gas in the carb with a syringe. I have some gasket material and I was thinking of just cutting one out for now. I soaked it in Pine Sol for a few days. It usually works pretty good at cutting grime. That particular area in the bowl you spoke of ( choke jet he called it ) I did not address but I will maybe this evening. 

'bradocross' says--Please forgive me RT325, if I have misquoted you.

All good & thanks for sorting any confusion. We talk Kiwi down here lol & doesn't always translate, plus i forget that most people go by what the parts list calls items. Cheers.

Still have the same problem.  I took the carb off and cleaned the crap out of it again. I did clean that "choke area"  you spoke of as well.  Carb cleaner and air will pass through all openings. I'm officially stumped. Ther again I have not checked crank seals or did any sort of leak down test or compression test. It does feel pretty normal as far as compression though. I may be officially stumped on this one. 

Any chance of a good length video with good audio of it running or won't it run long enough for that.

Wont run long enough for that. Lol.  I did fill the shizz out of the carb with a syringe today and it ran for about 5-6 seconds. As Insaid the gasket is nad and I mlm I fill t till it starts leak g it will crank and run a sec but that's it until I fill it again. Well I continued to put more in it after it started leaking and it ran long enough to rev it a couple of times