im taking my carbs off today to clean them up real good and also to see if any previous owner has installed a jet kit. and id liek to know what main and pilot jet yall would recommend i live in oklahoma i dunno if tht matters, my bike has a k &n and full d &d exhaust. i was told to run 140 jets on the outside carbs and 138's on the inside? any insight on this would be helpful and would a 40 pilot jet be good? i know the f3's come stock with 40 pilot jets any help plz and thank you

 

Check out the carb jetting database sticky. I'm sure I have seen people on there with a K and N filter with full D and D exhaust. In fact, I bet there are multiple people with that setup. See what they are running.

 

Stock CBRs run same size jets in all four carbs. Even jet kits use 4 jets the same size. Some people remember old air cooled motors that when modified for more power would need the bigger jets to cool the inner two cylinders more than the outer ones. Water cooled motors don't really need it as they don't have the big temperature difference since the water jackets cool every cylinder pretty much the same. Some highly tuned race bikes ran into cooling issues, but street use shouldn't be a problem. A Dynojet or other jet kit in a plus one size should do it. Full exhaust systems produce more peak power but usually lose low and mid range a bit.

 

well bought my bike and it had a vance and hines ssr. and was layed over and it scuffed it up. and my bike came with a brand new d&d but was missing the midpipe and i paid 125 bucks for a d&d header and midpipe and d&d muffler so now ill have a spare i guess. so i figured overall it would bebeteer in long run going with full exhaust. and after getting my carbs apart one of the previous owners installed a jets ket with 138 mains. jets say factory pro. an dhas adjustable needles. just having a hard time getting the carbs clean so it will run like it should. and had to order float bowl gaskets and float needles out of canada. float bowls were leaking badly. thts why i thought it was flooding but turns out just was gaskets. but im unable to remove fuel air screws cuz i have no tool. any ideas on how to make one or where to buy one. thanks for any and all help

 

See your latest post.

 

I just used a dremel tool to slice notches as talked about in the carburator cleaning and tuning stickie. Now i can just adjust them with a small flathead screwdriver. Gotta love CBRF!

 

Feel so lucky that in general uk bikes dont have any anti tamper setups on carbs, no drilling caps off etc, mix screws already slotted with an X pattern.

Good call on making sure the jets are stamped with the K logo, means you know what jet scale youre working with. Its crazy how differently dynojet/keihin/mikuni flow in regards to hole size.

All setups/regions/bikes are different but Think mines is on 138/140/140/138, one needle shim and mix screw about 2/2.5 to suit. Vastly different climate in the uk though, straight through perforated core exhaust and standard aftermarket pattern airfilter. 97/98 airbox/ram/velocity stacks and ignition advanced 3 degrees. Itll be like comparing apples and oranges in variables though.

Long gear driven L shaped screwdriver specifically for doing mix screws is a magic tool, saves pulling carbs to do just a tweak. You can pull the triangular and speedholed engine brackets off to get better acess under the carbs too.

These bikes are known to not like k&n filters, it'll be fine enough just not optimum, they like standard paper ones and that's tuned standard vs tuned k&n. There were comparitive dyno charts on here once upon a time before photobucket went weird. Its to do with airbox pressure / velocity, it's interesting but outside my scope. That being said if cammed/headwork then it might be beneficial. The factory hrc bikes ran with the paper stripped from standard filters and just the mesh i believe, different beast when tuned to near 110 wbhp with raised 14,500rpm limit, total loss etc etc

 

Detuned Cali bikes might run all 4 jets the same size standard but to my knowledge that's not the case for the 49state / rest of the world's early and late f3 revision model.

​Cant speak of wether running staggered main jet sizes is optimum but i'd imagine both setups rendered similar enough results. Id be curious to see dyno runs of both tuned setups and also how hrc ran theirs. Its pretty clear honda put a great deal of finesse into the induction setup and if they reckon run them staggered its probably for a good reason. 90s japan economic boom era research and development was pretty wild, a lot of time will have went into it.

Believe standard f3 jetting is 135/138/138/135 And not all jet kets are the same across all 4, some are staggered.