1980 yz 50 won't run with choke off

SOURCE: will only run with full choke and absolutely no throttle.

Carbs gummed up. Need a serious cleaning or a full ruubers replacement/rebuild kit. Gas turns to gummy when left stting in the fuel bowls.

Use a couple of cans of Sea Foam.. best stuff in the world.

SOURCE: 1984 aspencade starts w/choke and revs up, runs smooth. Take off

My 'wing won't run unless it has been warmed up some. I would suggest that you r&r your carbs to make sure the jets in the bottom are working correctly. They tend to get plugged up, especially after sitting & the aluminum flaking off inside... Rick

SOURCE: Bike only runs when choke is on

The carb jets are partially clogged and you need to clean the carb on the inside and out.

SOURCE: bike won't stay running without the choke out.

I also own a 1980 GS550L that had a similar problem, first thing I did to fix it is to add a can of seafoam to a half of tank of gas or less. The bike can run on pure seafoam if needed. Let it run for 3-5 minutes and shut if off. Let it sit for another 5 minutes then start the bike and take it for a ride. After 20 or 30 miles go ahead and fill the tank up with gas. Within a tank or so you should start noticing it idleing better and more power. On the GS550 the choke self adjusts as you use the throttle. There is no need to push it in the rest of the way. Even if you are extremely hard on the bike opening the throttle all of the way it will never go all the way in unless you push it all of the way in. I own two GS's and niether of which prefer to idle if I push the choke all of the way in. Once I did this and learned just to leave the choke alone and let it stay where it self adjusted as I rode the bike it has never stalled since at a light. You should be able to pick up a can of seafoam at any local autozone or advanced autoparts. Most likely your idle circuit on the carb is currently gummed up and the choke circuit is all that is that is working. Myself and freinds have used Seafoam to solve this problem and just about anything with a motor that was parked with gas in for an extended amount of time without any stabilizer added. It's well worth the $8 versus pulling the carbs apart.

SOURCE: ttr90. starts easily and runs smoothly on choke.

Remove and clean the carb. Sitting around can let the gas evaporate. This leaves a varnish residue in the carb. Remove the carb then remove the float bowl. Use a spray carb cleaner to spray into the jets and carb circuits. Remove the throttle screw and air screw and spray into the screw holes. The low speed idle circuit is the problem so concentrate on the air screw hole. Put both screws back where they came from and turn each until it LIGHTLY seats. Now back each screw one and one half turns. This is the factory setting. If the bike still does not want to idle, there is still some varnish or trash plugging up the idle circuit.