1996 Yamaha timberwolf problem

[austin123]

I bought a 1996 timberwolf 4x4 from the beginning it didn't run right so I rebuilt the motor everything except the crank shaft and it has a new carb on it runs better but now you can't give it much throttle before it falls on its face and dies I can blip the throttle wide open and if I let off it'll return to idle after a little stutter but if I hold in the throttle wide open it'll fall flat on its face and die I just set the valves when I built it cold ran it for a few then set them again after being warmed up what could the issue be I've cleaned the gas tank cleaned the carb and checked all jets and I try to mess with the air fuel screw but even all the way in while running doesn't affect the idle which I find odd any help would be appreciated. I'm suspecting carb somehow but I'm new to this still and I'm pretty lost. 

It will also when pushed wide open act as if your no longer on the throttle and will back fire from the carb and die you can ease in and get it up to high rpms but if you just gun it you're not going anywhere so basically loses power as soon as you do it dies completely and throws a white fog gassy mist out of the carb I've also tried with the air filter on and off and no change 

[davefrombc]

Check the float level. It may be set too low,  and make sure there is no restrictions in the fuel line or possibly  in the fuel valve.  Your description indicates to me  it is running lean/ out of fuel  at  wide open throttle.

 

[austin123]

The valve doesn't stop the flow the inside of the gas tank is spotless and fuel line was cleaned with the gas tank. As for float level I don't have a measuring tool to check it. I can include a video of what it sounds like when it happens.

[austin123]

I just went and moved the needle clip around and at the very bottom is where I'm getting the best results but still bogs out and dies at full throttle. Just a little update.

[austin123]

Okay so I fixed it but in the weirdest way I unscrewed the air fuel screw pretty loose so loose it wobbles around when you mess with it but for some reason that's worked needle clip very bottom and then air fuel screw being loose has for some reason worked now I just need an answer of why that is so I can actually do things the right way. Any help with that would be appreciated.

[davefrombc]

You only  need a small  ruler to measure the float height although gauges are easier to use accurately .From  your description  it still  seems to me to be running out of  fuel (  way too lean)  at higher rpm..  That can be because the floats are too low not allowing the  fuel  bowl to fill to the proper level, a restriction  in the fuel coming into the carb, a partial plugged passage or  possibly undersized  jets.  If you still  have the OEM  carb  for the bike try comparing jet size between it and your new one.  Sorry  I  can't help  more  than  offer those suggestions  to  check.

 

[austin123]

I'm gonna try to figure out jet size that's what I'm thinking I moved the clip all the way down and loosened that air fuel screw and it runs pretty decent now idles a little odd now but stays running I'm gonna go on a Google binge and see if I can't find the proper jet size it's a Chinese carb and I know they're notorious for having undersized jets I appreciate your help but for the time being my issue is solved pretty much.

[Tundra550]

Do you still have the OEM carb?  The Chinese ones are usually junk in my opinion.  That's probably your problem right there.  Get a carb kit for the original and you will be way better off.  

[Curtis Underwood]

On 6/24/2021 at 1:50 PM, austin123 said:

The valve doesn't stop the flow the inside of the gas tank is spotless and fuel line was cleaned with the gas tank. As for float level I don't have a measuring tool to check it. I can include a video of what it sounds like when it happens.

Get a clear piece of hose the size of the carburetor bowl drain tube. Put it on the bowl drain and run the tube up beside the carburetor. Open the drain and let fuel run into the tube if the fuel goes up to the lip of the bowl where it connects to the carb float is correct but if it is below that then the float is not allowing the bowl to fill up and stay filled during high RPM.