Main Jets

[Motorrad]

Has anyone else noticed the differance between ORIGINAL Keihin Main jets and the aftermarket ones (think they are sudco (stamped with a AB 168 (jet number)...

 

Yet another thing to drive me NUTS 

[Friar-Tuck]

Yes,
  There are several other jet manufacturers, Kehin and mikuni originals are all flowed.
   They are more expensive however they are more accurate.  I have had three occasions the off brand jet was the culprit.
     Tuck\o/

[Motorrad]

Good point Tuck..

I was reffering to actuall PHYSICAL design differance..

On Keihin branded jets, there is a Taper at the bottom of the threads (base) that seats into the carb..

On the AB ones I have... it is Straight cut.. and never feels like it bottoms in the carb... Just when it feels like ti does, the threads bust.. (I have never busted main jet's before I bought these ones)...

Also the external dimentions are the same... except for that taper, which on the AB jet.. is taller..

[Friar-Tuck]

And I also hadn't broken any Keihin's or Mikuni in carbs.

 Imagine my surprised when I snapped the main on a brand new 450CRF with the jets the owner bought for the project.
I had been surfing for what seemed to be the best bet and the owner bought the jets with the understanding I would help.
  (I wanted to go with JD but he wanted more jet for his money, oh well)
Brother my heart sank when I felt that snap. 
 I luckily had an easy out small enough to get the buggard jet out and used one of the Keihins I had from my box....
I wasn't even sure they would fit.   

 lesson 1: Use the torque wrench
          2 :  buy the good stuff
          3 :  FCR Jets are Same as PWK
  Tuck\o/

[Polar-Bus]

I buy nothing but OEM jets. While I cannot comment about direct experience, a buddy of mine had issues with EBC aftermarket clone jets not achieving correct desired jet change results.