Cant get it to idle

[AgusBarcia]

So i bought a used bike, and i cant get it to idle. I'll attach photos of the carb.

When it's cold, if i start it with the choke on, it starts right away for a few seconds and then it dies.

If i remove the choke then, it will only start when its going faster and the rpms are higher. I cant get it to idle, and the bike accelerates in rpm, drops and then dies. I already changed the intake gasket. If i give it gas it gets to high in rpm, if i let the gas go, it comes down and dies. I can accelerate it when its coming down, and it will mantain the rpms for a few seconds, and then accelerate in rpms.

What do you ppl think? Bad jetting, air leak, or pos carb?

 

[AgusBarcia]

So i found something out, prolly has nothing to do with it. The floater bowl (idk how its called) seems to have a minor leak on the gasket. But the thing is, that if i close the fuel tap on the fuel tank, i cant even get it to start for a second, as soon as i give it gas, it starts.
The stem that goes on the bowl with the jet, does it need to be submerged on fuel or not? Could it be that the level of fuel is not enough so that it cant get fuel on the intake at low rpm? I did clean it and i can blow through the jet, so i know its clean. I'm gonna draw what i mean as best as i can on paint.

 

[gary55]

The jet needs to be completely submerged in fuel. The symptoms you describe are similar to when you shut the gas off to a running engine. As the fuel is depleted from the bowl just before it dies it will rev up cause the jet is sucking air in with it's last drops of fuel. It acts lean like a brief vacuum leek. Make sure nothing is hindering normal fuel flow into the bowl, and re-adjust float to sink that jet, make sure the carb is all the way onto the intake and tight. You should be off to the races.

 

[AgusBarcia]

The float is not adjustable, but it didnt have a jet. So i jb welded one, and see how it goes from there. Also i was reading on this carbs, and they have a brass pipe with atomizers, where should they point? to the air filter, or to the intake?

 

[gary55]

Well ya got me bud. What kind of carb is it cause every one I've had the the floats were adjustable.

 

[AgusBarcia]

So, i got it to idle a bit high today, and when i rev it, it takes a few seconds to lower the rpm. So im guessings its rich, so gonna go buy a new smaller jet, and see how that works.
The carb is a chinese copy of a Dellorto SHA. I has the float and the needle connected, so there is no way i can change the height at wich it closes. I could get a longer or smaller needle, but ill give it a try like this.

 

[gary55]

Ok I stand corrected. I have a SHA clone but I never checked out the float to needle connection. I learned something new today. Generally when it takes a long time for the rpm's to come down after reving it indicates a lean mixture. The engines tend to run a little richer as they warm up. On the carbs that have a needle adjustment I get them running and warmed up. Then I crack the throttle full open really fast. If it has a hesitation or kind of a bawk then revs up real fast and take a long time to die back down they are to lean. Your only adjustment is changing jets so I would try this, and if you put in a fresh plug and run it for a bit you can read the plug for further insight to your mixture. There's a ton of info if you google reading 2 stroke spark plugs. Might have some of that jb you used blocking flow as well. that would make it lean.

 

[WINDY CITY BOB]

So, i got it to idle a bit high today, and when i rev it, it takes a few seconds to lower the rpm. So im guessings its rich, so gonna go buy a new smaller jet, and see how that works.
I have seen those small copy dellorto carbs, and the way that people would just have to take a piece of sandpaper and the it's got to be very fine sandpaper. And the twist the pin like a toothpick and round it out and not let the sun go down further it's more of an art than a science. That's why I would never use one of those I'm not knocking you for using it some people use them and have great performance out of them. However I just think that's a very poor design so I could be wrong
The carb is a chinese copy of a Dellorto SHA. I has the float and the needle connected, so there is no way i can change the height at wich it closes. I could get a longer or smaller needle, but ill give it a try like this.

 

[AgusBarcia]

So, gave it a ride today, on the block.
What do you think of the plugs? Is it alraight? When i took it, it was really hot ,i had to use a cloth to remove it.
Also couldnt make it idle, it sometimes idles fast, sometimes it dies... i guess i have a leak somewhere.

 

[Frankfort MB's]

So, gave it a ride today, on the block.
What do you think of the plugs? Is it alraight? When i took it, it was really hot ,i had to use a cloth to remove it.
Also couldnt make it idle, it sometimes idles fast, sometimes it dies... i guess i have a leak somewhere.

I'm sure it was hot because these motors run about 275-300 degrees!!

That plug looks good surprisingly, im thinking your oil mixture off maybe??? I'm not sure