These recommendations come from member mjm from the GSTwin
They come stock with 17.5 bleed type pilots, a number 60 mid-jet and 127.5 main
jets. The formunla seems to be -
STOCK - increase main jet one or two sizes, shim needle with a washer, pilot screws
out to 3 turns (to start) - most of the cold bloodedness goes away. If it doesen't, then go up one on pilot.
pods - Go up a few more sizes, and one more washer on the needle - I ended up at 142.5 before I did the exhaust.
Pods, Slip-on and Ignition advancer - up a few more sizes on the main - either 147.t or 150.
Another person on
the board indicated that they were increasing the mid-jet to 67.5 - I [mjm] have no idea how that works out.
That other person is Piper5177 who says the following in regards to a Stage 3 jetting:
I have been messing with this for a little while, and I have
just about got it. Changed the needles to the ones from the 89-00 Dyno Jet kit, DNO348. They are smaller than the stock ones
since they are for a 33mm carb and not a 34mm. But since they are smaller, the pilot did not need to be changed. I set them
on the fourth clip from the top. I changed the main to a 147.5, and it has great top end.
The only problem is with the smaller 60 main jet. Those jets
take care of the mid range up to around 6500 RPM. With the higher volume of air moving through the carbs they lean out until
the carbs hit the 147.5 jets. I ordered some 67.5 jets and those should clear up the little flat spot. I tried shimming up
the needles some more, but since the jets are lean the needle doesn't help at all. I have Vance & Hines exhaust and the
UNI pod filters [and they flow surprisingly well].
Flash from gstwin.com also writes:
I did notice on your "Why re-jet a stock US bike" page you listed Part Number - 09420-40014 for #40 pilot jets. Could this
possibly be a misprint? Maybe an old part number? I'm assuming you were referring to Suzuki Genuine Parts.
The reason I asked is because I went to my local suzuki dealer with this number (you have 09420-40014 listed) and he said
it did not exist. He told me the first 5 digits did not match up under the Suzuki Genuine Parts Catalog, but the last 5 digits
did: part no. 09492-40014 What was funny is he told me the description just said "pilot jet". Since he knew I wanted size
#40 he told me there was part no. 09492-40018 which had the description "pilot jet 40". I'm not sure if these were possibly
bleeders because the pilot jets I ended up ordering (part no. 09492-40014), which were the ones which matched yours the closest,
ended up being what I wanted: 1 Mikuni #40 non-bleeder pilot jet.
I suspect the number difference is due to ordering it either through the dealer or through bikebandit.com or ronayers.com
which would explain the differing first sequence of numbers but matching second set. fwiw, pablo-