Help, No gas to cylinder on my 81 yz 125

[kcmastr]

Hi everyone, new to the forum but after browsing through alot of posts still dont have an answer. I bought this 81 yz 125 for my daughter to learn on but am spending way too much time working on it instead of her having fun. Never worked on bikes till this one. Okay, the problem seems that I'm not getting gas to the cylinder. Bought new carb and out the box is spewed fuel out of both over flow tubes but started up. Figured float problem and opened it up and did minor tweak. That seems okay now but I'm not able to start without giving it a bit of gas through the top of the plug hole. Checked for dirt and blockage. I am getting gas to the bowl, lowered float with bowl off and gas came out. I'm completed perplexed! Any ideas?
Also new plug installed and has spark!

[Woody_393]

Moved to the Yamaha 2 stroke forum.

[stormbringer]

Does the bike idle? How well does it run?

[kcmastr]

Once its started it idles and took it for a run up and down the street. Seemed to bog down after a turn but I let off the throttle and then throttled it back up slowly and it ran normal. Also When I'm letting it idle if I goose the throttle it idles fast and takes a second or two to throttle back down to normal idle. It sounds like a fuel problem but I cant find it. What forces the fuel into the cylinder? Ive checked the plug for wetness and dont see anything. Thanks for replying!

[stormbringer]

I would start off by checking the reed valves, if the petals a not flush or even close to being flush with the block, or they are cracked/damaged, I would replace them. I would then check the float level and make sure it is in spec. I would also check for any air leaks, they would be around any area where a seal or gasket is needed. I am sure that there is more information about how to go about doing these things in another thread on this site.

[Faded]

Originally Posted by kcmastr

What forces the fuel into the cylinder?

The link will help explain what's going on, [Only registered and activated users can see links. ]

I would check for an air leak, especially on a bike that old. This will lean the jetting making it hard to start and can be responsible for the stumble when you get on the gas. What's the condition of the top end? A simple compression test will let you know if it's mechanically capable of properly supporting combustion.

[kcmastr]

thanks for your help, I will check all the areas. I looked at the reeds but dont see anything visably wrong with them. I do notice that there isnt a gasket between the reed and cylinder. I tried spraying around the area while running but didnt hear a change in idle but I'm suspecting that it should have a gasket anyway!