Am I running lean?

I'm trying to dial in my carbs right now. I think I've got everything right with the motor, jetting, and needle position. I've got a smooth response across the RPM range -- EXCEPT, I still get a little bog right off throttle when starting from a standstill. It's a little intermittent and seems to get a little worse as things warm up. Riding in the city means many slow starts (pulling away from a stop sign orred light) during the day, so confidence in this idle-1/8 range is critical. When I blip with throttle, sometimes it totally chokes.

My bike's details are below. I've got my mixture screws at 2 turns out. Should I keep adding fuel 1/4 turn at a time, or am I missing something? Do I just have to live with this?

VM26ss with KN pods
Pilot-20, Needle clipped 2nd from bottom
Fuel level checked via clear tube
4-1 Pipe with baffle
Dyna ignition and coils
Stock cams
Valve clearances OK
140-150 compression.
I'm ~1200 feet above sea level.

richrand wrote: I'm trying to dial in my carbs right now. I think I've got everything right with the motor, jetting, and needle position. I've got a smooth response across the RPM range -- EXCEPT, I still get a little bog right off throttle when starting from a standstill. It's a little intermittent and seems to get a little worse as things warm up. Riding in the city means many slow starts (pulling away from a stop sign orred light) during the day, so confidence in this idle-1/8 range is critical. When I blip with throttle, sometimes it totally chokes.

My bike's details are below. I've got my mixture screws at 2 turns out. Should I keep adding fuel 1/4 turn at a time, or am I missing something? Do I just have to live with this?

VM26ss with KN pods
Pilot-20, Needle clipped 2nd from bottom
Fuel level checked via clear tube
4-1 Pipe with baffle
Dyna ignition and coils
Stock cams
Valve clearances OK
140-150 compression.
I'm ~1200 feet above sea level.

If not already done, would consider:
Use stock middle clip position on jet needle;
Visually inspect plugs for fat blue spark;
Assure function of timing advancer by watching it under a timing light --should immediately move back and forth as the throttle is blipped;
Perform running sync on carbs;
Assure ignition timing is spot on (use timing light).


Good Fortune!

thanks patton. I'll check the timing and the sync.

Go to a 17.5 pilot, a 20 is way to big for your engine. That should fix it or make it better. If the problem does not completely goes away with the 17.5 pilot then move the needle clips to the middle slot but still leave the 17.5 jets in..

One of the techs at Z1-E also suggested I use a 17.5 and also drop to the second slot from the bottom (is that the 4th slot?). I took that advice and it just didn't run right. Better than how the PO had it setup, but not right.

I found this thread: www.kzrider.com/forum/3-carburetor/175569-kz1000-jetting

wiredgeorge suggested using a 20 for the Kz10O0A1 so I put them in. It largely works and is a noticeable improvement. I'll check the timing and sync and if nothing is out, I'll trying moving the needle back? It pulls strong from 1/8-ish on up. This problem is exceeding my carb-theory knowledge.

The symptoms you describe are that of being too rich.

Blipping the throttle is richer than slowly opening the throttle, so blipping is worse if you are rich.

As the bike gets warmer, the fuel atomizes better, so a lean condition will get less noticeable as it warms up. Since yours gets worse, it is likely too rich (not surprising since you are at a higher altitude).

If the tech said to raise the needle, that would be the wrong direction for a rich condition. You want to lower the needle.

I agree on going to a slightly smaller pilot.

And possibly lowering the needle (moving the clip to a higher position on the needle).

Thanks all. I'll rejet with the 17.5s and start with 1.5 turns out and see what happens.

richrand wrote: Thanks all. I'll rejet with the 17.5s and start with 1.5 turns out and see what happens.

Like the others have suggested the pilot it rich.

The real trick to dial in your pilot jet is to keep reducing the pilot jet until the mixture screw does nothing then go back to the one before it.

richrand wrote: I'm trying to dial in my carbs right now. I think I've got everything right with the motor, jetting, and needle position. I've got a smooth response across the RPM range -- EXCEPT, I still get a little bog right off throttle when starting from a standstill. It's a little intermittent and seems to get a little worse as things warm up.

That sounds rich to me. Either pilot jet or needle position adjust.

richrand wrote: One of the techs at Z1-E also suggested I use a 17.5 and also drop to the second slot from the bottom (is that the 4th slot?). I took that advice and it just didn't run right. Better than how the PO had it setup, but not right.

Running pods often means it never again "runs just right".

Running pods often means it never again "runs just right".

Pods are so awesome for letting me get the carbs on and off quickly in order to keep making adjustments to compensate for the fact that I have pods.

richrand wrote:

Running pods often means it never again "runs just right".

Pods are so awesome for letting me get the carbs on and off quickly in order to keep making adjustments to compensate for the fact that I have pods.

100% agreed. No offence to anyone but if you cant dial in carbs with pods then either you aren't doing it right, not spending the appropriate time required to get it right or there are limitations of not having access to the proper (different) needle and slides to tune. But I will say I prefer the keihin over mikuni for tuning reasons.