Worn carb needle

[RichardMott]

Question for the brain trust,

What are the signs of a worn Mikuni carburetor needle?

[dirtsquirt80]

um you see wear on the needle. is this a trick question Rick?? whats the sign of bent handle bars?? lol

[JayLael]

computer trouble caused double post Can't delete

[JayLael]

Many years ago when I got my first Hodaka, an Ace 90, someone had bent the slide (metering) needle, probably installing the slide. These were the old ones with the idle speed adjustment on the top. Apparently after running it like this for years, the needle jet metering hole was worn oblong. You could see it was egg shaped looking down into the hole where the slide goes in. Boy that sucker ran rich! IDK if this is any help, but that's my story.

[BrianZ]

Here is a pic I posted a while back showing a good needle jet and a worn needle jet. Of course, if the needle jet is badly worn the corresponding needle will also need replacement.

Oh yeah, the Dirt Squirt this needle jet came out of ran really rich!

Brian

[Zyx]

Rick,

If I understand your question, the answer is a rich running bike that didn't used to run rich.

[dcooke007]

Here is another pic of a needle jet that should be replaced. On this carb the jet needle and needle jet entrance looked good. However, when the carb was assembled, installed and the bike test driven...well lets just say it did not lack for fuel. Needle jet bore in this case was damaged by corrosion and maybe a little electrolysis.
Danny

[RichardMott]

Thanks guys,

I just cleaned the carb on my TY 250 and the bike seems to take off at about mid-throttle more quickly than I expected. I thought maybe a worn needle or jet would explain that. It could be I am just not used to a 250 CC dirt bike. Although, I have a 550 CC Yamaha street bike.

[Zyx]

Just to be clear, your 250 takes off too fast??

[Bullfrog]

Note that a worn needle and/or worn needle jet would not improve performance and cause your big bore to take off too fast - symptoms would be more like the opposite of that.

Ed

[ossa95d]

A lean condition in low throttle openings might cause the bike to bog and then as you crack the throttle open cause it to jump to life. This may be the condition you are experiencing. Most likely not a worn needle or needle jet. I hope this helps.

[RichardMott]

No bogging. Smooth throttle up to that point. My potential buyer will ride it Tomorrow morning. He already has a TY 250, so I will let him see if it seems unusual to him compared to the one he has.

Thanks all...

[RichardMott]

No bogging. Smooth throttle up to that point. My potential buyer will ride it Tomorrow morning. He already has a TY 250, so I will let him see if it seems unusual to him compared to the one he has.

Thanks all...

[viclioce]

Let me know what size your needle is. There's markings on the side of it. I may have a spare I'll give you, IF I have the correct one for you! ; Victor

[RichardMott]

Well, I started it, he heard it run, never rode it. Gave me a check. Bike is his now. He just might use it for parts. He already as a TY 250.

[viclioce]

Well congrats on the sale, I guess! ;D Victor