do jet needles wear out?

[Nevada Sixx]

hi,
im about to order some parts for my mikuni carb.. i was wondering if i should order a new needle as well as my other parts.
Do those wear out?


thanks..
sean, 89 yz 125

 

[rlindsey]

I have had them wear. But more noticeable on big 4 stks.and old Maicos. The needle jet seems to wear more than the needle though.

 

[Durt Cycler]

I never heard of a moderm dirtbike carb needles wearing out but I heard that some type of 2-stroke oil will eat away at the gold color....:think

 

[NO HAND]

If the needle jet and needle are worn out, you will know by feeling a uncurable rich spot from 1/4 to 1/2 throttle where the straight section of the needle should seal better. This happens when the straight section of the needle and the nozzle has been rubbing together for so long that it became out of specs. Only your seat of the pant knows if you have that rich spot or not.

 

[jaguar]

from idle to 1/4 slide open (about 1/8 throttle open) the clearance between the needle jet and the needles straight section is in play but if the needle jet is wallowed out then jetting will be too rich throughout the whole throttle range. WOT isn't just the main jet.

 

[jaguar]

this site covers the subject well: needle jet, emulsion tube, mikuni, keihin, carburetor, troubleshoot