Rough Running at 3000 rpms

[johnfrenchsr]

I recently had the carburerators rebuilt. They had 150s in them. The kit came with 130s. And I had them synchronized. Between 3000 and 4000 rpms, it runs rough. Higher rpms it runs fine. All my plugs look like black carbon, except for one. Do I need to run a hotter plug or is it my coils or do I need to have my carbs redone? Thanks.

[TopCatGr58]

Hey JohnFrenchSr,

IF your kit was a K& L kit, then that's the most likely problem, along with the jets, the Pilots moreso than the mains. They are notorious for being the wrong sizes!!!! Hopefully you kept your old pilot jets! If not, there are many places to get the true Mikuni jets, and then just replace them! This will probably fix your problem, but afterwards, you may also need to adjust your floats as well, but try the jets first!!
T.C.