went to K&N.. now it wont run..rejet help!

[80GS450L]

1980 GS450L.. i'm turning it into a "bobber" style bike... i went with the K&N replacment cone filters .. now the engine spits and sputters at low RPM.. i know i gotta rejet.. what jets need changed?(and what size) help!!!

[KEITH KRAUSE]

No 450 experience. But if stock exhaust, try 3 to 4 full sizes (15 to 20) up on the mains. Then raise (shim) the stock jet needles up about .70", then 1 full size up on the pilot jet and up a size on the pilot air jet. Remove any float bowl vent lines and leave those ports open.
Just guesses mind you.
Take plug reads at 1/3 throttle position for the jet needles, and full throttle for the mains. Do what the plugs/performance say.

[80GS450L]

alright i found the numbers... 115 for the big one... 17.5 for the little one... i'm thinking the little ones have been changed already?...

so should i go with say a 20 on the little one and a 116 on the big one?

also i looked in the dennis kirk catalog.. i know i have mikuni carbs... i THINK i found the right big ones but there are no little jets in the book that i can find??

sorry i dont know exactly what all the parts are called..

if anyone has part numbers it would be a HUGE help

[bgmart450]

Those are the stock sizes you had in there. Stock suzi part #'s are:
09492-17005 Jet, pilot (17.5)
09491-23012 Jet, main (115)

Hope that is of some use to ya.

[KEITH KRAUSE]

I'd say if the stock mains are 115, then try 3 full sizes up...that would be 130.
A larger pilot jet would make sense...a 20.
You'll also need to get a larger pilot air jet as jet kits generally supply. Don't know your stock pilot air jet size. Go up 5?
Most importantly, raise the jet needles by shimming, unless you're model is not U.S. and could have adjustable jet needles. You spend the most time riding on the jet needles so don't over look them.
Actually, I suggest not running pods on a 450. You'll almost certainly experience some low end torque loss and a little mid-range loss. Not the best thing on a smaller motor. You won't gain a whole lot on the 450's top end power. Some, if jetted spot-on, but...
Just my opinion.

[80GS450L]

i already have the pods so i'm gonna run them(i've had them for years) i dont mind if i lose some low end.. i just dont want it to bog down like it does when i rap the throttle in neatral(or driving) higher RPM its great zero bog...

i found the right mains... BUT the only pilots i've found.. look like the right ones.. but have little holes in the lower "shaft" part of the jet??

my stockers dont have the holes?

ordered everything hope its right

now if i ever want to go with a more open exhaust will i have to rejet again?

[80GS450L]

damnit.. i ordered the wrong ones can anyone tell me what carbs are on a 1980 GS450L? or better yet the exact dennis kirk part number?