1977 kz650 pods and open exhaust... Base thoughts?

So with my recent rewire I lost my airbox and attached pods. From what I can ascertain from my plugs I am running a bit lean possibly. I am getting some stumbling and hesitation from just before half throttle. It makes good power until just before half throttle and it idles really strong just up not is no bueno. Anyone have any idea for a base line figure... Clip position, jet sizes?

Put the baffle back in the pipe and it will be easier to jet and it will run better under a wider variety of conditions. Same with the pods. Running individual filters will make the bike much more sensitive to changes in weather.

this is a bit foggy to recall from 1984, but I ran my mostly stock KZ650B with drilled out air box Kerker header open with no muff. Had carbs jetted to 112.5, metering rods were 1 notch dn (rich) from mid or in mid pos. I think i remember 5 positions to them?
Ran the best it ever did this way but it was only for the strip, balls out.

i just jetted my 81 650, i went ahead and got the dyno jet kit. it came with 118s (and 124, 122) and went to 17.5 on the pilot jets. it stutters a bit at low rpm but when you get past that it roars. its a start at least.
Also if you dont want to put the baffle in try this little mod..
www.nightrider.com/biketech/exhaust.htm

TerryK wrote:

Put the baffle back in the pipe and it will be easier to jet and it will run better under a wider variety of conditions. Same with the pods. Running individual filters will make the bike much more sensitive to changes in weather.

It is baffled just not much of a baffle.

At half throttle it would be your needle.

+ 1 on the baffle
open exhaust is for a drag bike,all high rpm
it will pull out of the corners better with a baffle installed

A general rule when changing to 4to1 and pods is to up the main jet by 3 and the pilot by 1. That is just a starting point, you may need to increase or decreas the main depending upon pipe flow. But you first need to get the needle setting correct.

You do not indicate if you are using the stock carbs or not, but IIRC the stock carbs are vm24ss and came with 102.5 mains and 15 pilots. So a good starting point would be 110 mains and 17.5 pilots. I do agree that issues with mid throttle are most likely a needle issue. Since you get a stumble just before 1/2 throttle I think it is just a bit too rich. Try leaning the needle by moving the clip up either one notch or shim it a half notch. It that does not solve the issue you may need a leaner needle.

Step 1: DETERMINE THE CORRECT NEEDLE AND OR NEEDLE JET.
Whether or not your carburetor is a MIKUNI or a KEIHIN, it does not matter. This is the most important step in jetting your carburetor--period!
1. Remove the main jet.
2. Place needle clip in mid-position.
3. Start motor and run it on the stand.

Condition: Motor running and main jet out. Needle or needle jet is correct: Carburetor should run clean to approximately 3/4 throttle. From 3/4 throttle to full throttle, the motor should start to break up as a result of too rich condition.
Correction: None needed.

Condition: Needle or needle jet is too rich. Carburetor runs clean to approximately 1/2 throttle but breaks up before 3/4 throttle as a result of too rich condition.
Correction: Mikuni replace needle jet with next leaner and test again. Keihin replace needle with next leaner diameter and test again.

Condition: Needle or needle jet is too lean: Carburetor runs clean beyond 3/4 throttle and has an erratic throttle response.
Correction: Mikuni replace needle jet with next richer and test again. Keihin replace needle with next richer diameter and test again.

The emphasis here is to find the correct needle or needle jet diameter, which will allow more fuel to pass than is needed but not so much that the needle itself has no control below 3/4 throttle.

So where would be my best place to source jets?

I am sure there are many online locations but I would suggest Z1Enterprises

www.z1enterprises.com/

gd4now, do you suggest running it on the stand because you are putting it in gear or so that the bike is as level as possible, or were you not even talking about the center stand?

Was not suggesting you put it in gear. Did mean to have it level as using only side kickstand can effect level of fuel in bowls.

Whew, that's a relief. Gettin' into the mains, or even the needle, with it in gear on the centerstand sounds terrifying.