Jetting Question

I am buying a 4-1 V&H exhaust and EMGO Pods for my KZ650 and I need some help deciding on what size jets to start out with. From what I have found the place to start is 117.5 Mains and 17.5 Pilots and the needle in the center. This sounds good but my bike seems to be one of the leaned out ones from the factory as the stock main jets are 90's so will this setup be ok. BTW I plan on going no baffle on the pipe. Also I have read that the pods can be hard to get running right. Will I be better off going with the K&N high flow single filter that goes in the stock airbox? Any help or insight will be greatly appreciated!!!

Ok, after reading more I have decided not to hastle with the pods and go with the K&N single filter in the stock air box. I think the 17.5 pilots will still be fine and im thinking of starting at somewhere between 110 and 115 for the mains. Does this sound correct? Keep in mind that i am running straight pipes. Thanks!!

Good choice on the stock air box (not a pod man myself) I run a Kerker 4/1 with K&N in box and I (still surprises me)run 17.5 pilots and 105 mains. I keep my Kerker tightly packed with stock baffle system. Always thought that it should be a little lean but bike pulls soooo hard to redline and plugs are a tannish/gray color so seems to work for my bike. I think your good with 110's and 17.5's. Question.... how do you guys get away with tunning an open pipe? I've opened mine and it's really loud! I would not even think about running around my area with an open megaphone.

Well I love the sound and based on how the harley guys ride around here with straight pipes im just tryin to keep up with them lol. Thanks for the help, any other opinions would be great thanks!!!

I got everything on and i have it setup with the K&N filter in the stock airbox and the baffle with all the packing removed from it and just the metal baffle pipe in the exhaust.The only problem I am having is some backfireing when i decelerate. The current setup is 110 Main jets, 17.5 pilots and the needle is in the middle slot. I know it must be lean causing the backfiring, but do i need to move the needle clip down or go up in main jet size?

Have never messed with a 650 but my 1000 is running 28s with accelerator pumps/115 main jets/17.5 pilots kerker 4into1(open)pod filters.motor is otherwise stock.it runs great but if you (snap) the throttle wide open it blows out a godawful cloud of black smoke for just a second then clears up.

onuLine57 wrote:

The only problem I am having is some backfireing when i decelerate.

Mine only does than when the pilot jets are too small (too lean).

onuLine57 wrote:

I know it must be lean causing the backfiring, but do i need to move the needle clip down or go up in main jet size?

I don't think either of those is the best knob to twist.

FIRST: make sure the fuel levels are right (clear tube).

MAIN TOO SMALL: wind the bike up full throttle, does it pull strong to redline? If yes, main jet is right.

Needle clip helps if you have hesitation coming off low throttle opening.

I dont think the pilots are too lean as there are people who run 17.5 with pods and all i have is the single k&N filter but I might be wrong. Fuel levels are fine they have been checked with the clear tube. It pulls to redline and there is no hesitation. I dont think it is a vacume leak as the intake boots were replaced last year. Any Ideas? Im going to look at the timing later but is should still be good.

Im having trouble deciding if i need to jet up another size. The idle is great and ther is no stumble off idle so i think the needle is ok. There is a bit of gold on the header no near the head which i assume is normal because i see this on most bikes or is this another sign its getting too hot because it is lean? At times it seems a bit lean at wide open throtle. Im going to recheck the float level this week.

backfireing when you decelerate can also be reed valves if you have them.