TOPIC:

Just got done with the restoration. Put in new rings have 135 psi compression all 4 cylinders +/-(5psi). The carbs were mechanically synched, and the timing was also done statically. I put a 120 main jet in after putting on K&N pods and a V&H 4:1 exhaust. I am living at about 2800' and here is how she runs.

Idle is quite smooth and it fires right up. My plugs have been a little sooty but not wet. Im running a B7ES which is the hotter of the specified plugs. The bike does not miss at all, but there is some hesitation and a very minor bog during heavy acceleration.

My first instinct is to go with a smaller jet size and keep plugging jets in until it runs right. Just wondering if their are some preliminary steps I should take to ensure its jetting i.e. pulling the pods and run filterless to lean out a bit? How about pulling the baffle to reduce restriction? How big of a jump should I make from the 120? The jets were a 112.5 prior to the rebuild.

Needle clip position?
You can also tape up half the filter area of your pods to see if it is jetted lean.
I would of went 105% on the mains and raised the needle 1 to start and I'm at half you alttitude.
Maybe go back to stock jets and raise the needles and compare it with what your running right now.
That would be cheaper than buying abunch of jets.

Nebr_Rex wrote: Needle clip position?
You can also tape up half the filter area of your pods to see if it is jetted lean.

I am already running very rich, wouldnt this just make things more rich by reducing the air flow further?

calvin17d wrote:

Nebr_Rex wrote: Needle clip position?
You can also tape up half the filter area of your pods to see if it is jetted lean.

I am already running very rich, wouldnt this just make things more rich by reducing the air flow further?

Yes,just stating for reference,no harm intended.

If not already done, would visually observe spark (look for fat blue).
And also assure fuel level in float bowl is within specs (use clear tube test method).

Would replace spark plugs with brand new NGKB8ES and toss the too hot #7 plugs as they are often just a crutch to help compensate for something else wrong.

Good Fortune!

Patton wrote: If not already done, would visually observe spark (look for fat blue).
And also assure fuel level in float bowl is within specs (use clear tube test method).

Regarding the fuel level in the float bowl, the spec in my book suggests 22mm +/- 1mm. Is this measurement from the bottom of the float to the mating surface of the carb or at the flange that sticks up off of the mating surface for the float bowls on the carb?

Is a rich condition a sign of too high a float level?

How can I be sure that the "fat" size of my spark is "fat" enough?

calvin17d wrote: ...120 main jet...K&N pods...V&H 4:1...2800'...plugs have been a little sooty but not wet...B7ES...some hesitation and a very minor bog during heavy acceleration....

For reference, courtesy of Z1E:

26mm (VM26SS) KZ900A4 & A5
Main Jet 115
Air Jet 1.0
Needle Jet O-6
Jet Needle 5DL31-3 (last number is the clip position)
Throttle valve (slide) 1.5mm cutaway
Pilot Jet 17.5
Air Screw setting 1 3/8 turns out

Good Fortune!

At 2800' elevation, 120's may be too rich for your setup. As pointed out look for the fat blue spark on all cylinders. I suggest you check the spark color indoors. Outside the spark will look more red than blue. I like to test for good spark by using a new plug with the ground strap removed. Then the spark must jump all the way from the center electrode the the thread ferrule.

Forgot to say that Patton is also correct about going back to the B8E plugs.

What is your small jet size? How much voltage do you have to your coils? Roy

calvin17d wrote: How can I be sure that the "fat" size of my spark is "fat" enough?

I love this question

If it is bright and light blue, and jumps a cm gap in the air, you're good to go

My new dyna setup had a nick in the plug wire and the spark would jump over an inch to the frame with a bright blue "CRACK", thats what you want!

PS. Remove the plug and use a screw driver. You want to see that spark JUMP to the engine.
Gloves optional, the spark wont kill if you use one hand. Just tingles...

Wow, that screw driver method worked great. Had a big "fat" blue spark that I had jumping about 3/4" to my engine. My next investigation will be the float level.

What are thoughts on raising the needle while in the carbs?

calvin17d wrote: ...next investigation will be the float level.
What are thoughts on raising the needle while in the carbs?

Would leave the jet needle clip in the oem middle position.

As to fuel level inside the float bowls, that is the critical factor, regardless of the measured dry float height while carbs are upside down on the work bench.

Where fuel level is within specs, the carbs couldn't care less about the dry measured float height.

Use the clear tube method and forget about measuring the float heights (unless the fuel level is so far off that it becomes helpful to adjust the float height measurement as a means to getting the fuel level in the ball park close enough to obtain the correct fuel level by using the clear tube method. See image below.

Good Fortune!