Hi all, I finally got my CT1-C running. I can only get it to idle when the idle screw on the carb is turned completely in and then it is really slow and will die with out a blip of the throttle eventually.
Some background; cleaned and replaced most every component in the original carb. Good connection to the engine. Spark is great. The ignition looks almost new with no screwdriver marks that I can see. Best part about this bike.
I got a Bassani after-market exhaust pipe on it. It was really clogged with hair (not packing) or something. I pulled the end off and sent hours pulling crap out and blowing it out buy running the bike. I had the top end bored to a 2nd over and replaced the piston and rings with the proper size. It feels very good and starts and runs pretty well. I don't have the chain hooked up yet so i can't ride yet. Some more work to be done there.
Anyways I don't really know why it does not want to idle. The choke seems to work. Closed when cold and opened it pretty soon after start up. Once warm it would stall if I closed it again. Normal..
The air screw does not really seem to change the idle speed too much. It will stall if I turn it completely in and does increase the idle speed slightly but no major change. Revs clean but taking it easy on the new bore.
Bottom line is it needs to have the idle adjustment completely turned in to just keep it at a very slow idle speed at best and a crack of throttle to keep it from stalling after 20-30 seconds of idling on her own. Any thoughts? Thanks in advance for any comments.

Timing off?

Did you replace your carb parts with genuine mikuni or aftermarket ie keyster I also have a CT1C 

Verify the timing is right with a dial indicator. Set 1.8mm BTDC. I expect your problem is really gonna be in the idle circuit in the carb being stopped up. Pilot jets are very small and easily varnish over.
 

Thanks for the replies. All noted. I will look at the carb again. Also I noticed a couple of drips of gas coming from the left side cover. Looks like the crank seal is leaking. It has been sitting for 24hrs and there are about 3 dime-size drips directly under the left side cover..Would that be enough to create a problem? I will fix ASAP.
Thanks again.

Generally, air leak or lean raises idle.

Too rich, lowers idle... maybe flooding or flooded?

I would go out and ride it for a while before going too crazy with "fixes". You can't really warm up and "clear out" a loaded up engine by idling and revving a little. I've had bikes that will barely idle after first start then idle at 3000 RPM after a good ride.

Yes it will be a problem buy seals for a 77 to 79 IT175 Yamaha they are double lipped your bike will run better 

Compression good?, i see 'new bore' so should be nice & bouncy on the kick start. Crank seals good. Base gasket not sucked in around the transfers. If carb mixture isn't responding i'd look at the pilot jet--idle mixture jet. Hold it up to the light--or run an accupuncture needle through it like i do lol. Think you said constipated exhaust--here's mine from long ago haha. Scroll down a bit. Sorry if it puts you off your dinner. One more thing--points gap & timing 'up there' & not points closed down so timing retarded.
photos.app.goo.gl/vgrbgFzJHtjr8iky9
Apparently i'm mucking up posting the link. Should be good now. If all fails ask a child--so i did haha.
 

Thanks again for the replies! I will get the IT seals. and yeah I will look at the carb again. I really like the original carb. I bought a cheapo carb and it does not clear the engine; the bottom is too tall. I filed it down and I got it to fit but...no don't do that...I will take a look at the pilot jet and just go over it. If I can't fix it after that I will try the cheapo carb and see what happens. I really think the timing is spot on. It starts 1st kick, revs good, and seems to have good compresion. I am used to kicking an MX360 and a DR370 4 stroke so I may not have a good feel for a 175. I pushed it with my hand it and feels pretty good to me. It does not have the chain on yet. Still working on the rear wheel so I cant put a load on it to really tell. I just have a junk wheel on it with no sprocket and a flat tire.

Thanks Mark, Could be not so bad. I do want to replace the crank seal. The wheels are the next thing I need to get fixed up and on. Replacing spokes and getting tires. Forks are pretty much done. The rear end will hold for a test ride.
I am putting on a NOS 3.5 18 IRC up front and a 4.0 18 IRC Tractor in back. These are old NOS tires. They are 6 ply and thick...  Any experince with IRC tires? I am a desert and fire road off roader in So Cal.