rejetting carbs

[svsteve]

I'm gonna be pulling my carbs this winter for a good cleaning. Its been 22 years I have the bike and I feel it can use a freshening up. So since I had the bike after doing glasspacks and K&N filter I always had a bit of popping in the exhaust. It seems to be getting worst, that's why I figure I'll clean them up. I have a question and would like to hear thoughts of others here on the board. I'm thinking while I have the carbs out I'd bump up my jet sizes. Seem I could go to 38 and 105 on pilots and mains. Does this sound like a good idea or should I stick to the 35 and 100 jets. Lots of knowledge on this board, that's why I ask. Thanks Steve

[98valk]

stay with stock jets.  popping is either vacuum leak or idle mixture screws need to be opened more.  remember all gas engines pop when going off throttle due to the engine going temporarily lean.  with open exhaust it is heard.  mufflers stop one from hearing it.
so only way to eliminate it with open exhaust is to open up mixtures screws to a very rich setting, mpg will drop along with performance and will have gasoline odor from the richness.

[Ricky-D]

Yep, pay attention to CA.

Leave those jets alone.

The Valkyrie runs plenty rich already, even when you mess with the exhaust and air cleaner.

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[Bret SD]

I made the mistake of installing #38 jets recently, bike runs great but mileage sucks, 26 mpg. I also have a problem of surging idle which I didn't have before the 38s.

Just got new #35 jets in the mail, can't wait to install them, right now I'm too tied up to do it..  frustrating as hell..

#38 jets 

[Forge]

I’m running stock exhaust on my ‘99 IS. I installed a K&N drop in filter and decided to try a 105 jet which is 2 steps above stock. It was mushy and very rich smelling when I would let off the throttle after romping on it. I don’t know if the 102’s would work any better than the stock 100’s, but after going back to the 100’s, I’m happy I went back.
  As for the 38’s, I did that and also went back to the 35’s. The 35’s gave me crisper response.

[WintrSol]

I had the same results with the #38 pilot jets that the PO installed. You can adjust out the rich at idle, but it is still extra just off idle, and I got some of that smell, and fuel economy wasn't what I expected. Now back to stock, and it never ran better since I bought it.