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These blasted carbs have me at my wit's end.

I installed the new OEM needles and seats, with new o-rings. I reset all the floats to spec, put back in the bigger main jet (friend put in a jet kit for me) and reset the needles to the middle clip position.

It's still running rich. I pulled and replaced the spark plugs, old ones look carbon fouled. I also adjusted the mixture screws ( http://screaming3d.com/pics/bikes/Kat/carbs/2.jpg ) to 1.5 turns out, instead of the 2.5 I had them at after doing the needles and seats.

The thing is *still* rich when you get a little bit on the throttle. Also, it will die if you crack the throttle open to even 1/8 open, quickly.

I'm doing this with the airbox off, since it's a 10 minute grunting affair at best to put it on.

Carbs were completely gone through before the jet kit was installed.

Wrenched on it some more, I believe I have a vacuum leak between the carb boots and the head. Spraying starter fluid in that area makes the RPMs instantly jump up by about 2,000 RPMs.

Now, to get the screws off those boots when they are fighting me tooth and nail.

Skier wrote: The thing is *still* rich when you get a little bit on the throttle. Also, it will die if you crack the throttle open to even 1/8 open, quickly.

I'm doing this with the airbox off, since it's a 10 minute grunting affair at best to put it on.

You probably realize this now (Since your second post) But that indicates your bike running lean. It's lean because of the leak but also because the airbox is off. You Must adjust the carbs w/ the airbox on. If you know the carb is set up as it should be, then that's great. Put the airbox on and concentrate on getting them tuned. You'll also need to synchronise them.

I am in the process of ordering the o-rings that go between the cylinder head and the carb boots. Should fix my problem, I think.

I'm also looking into pod or oval filters so I don't have to mess with the stock airbox.

Skier wrote: I'm also looking into pod or oval filters so I don't have to mess with the stock airbox.

I went this route with my old Yamaha ... Stock airboxes are a PIA, but do serve a legitimate purpose. Hold on to it in case you don't like the pod results

What kind of different behaviour are we looking at with the pod filters? I thought they would just make the mixture a bit lean until you fixed that up.

Pods can be unpredictable.

One thing an airbox does, is to create a relatively constant resevoir of air for the engine to drawn in. This makes consistant jetting much easier.

Pods are hangin' out there in the wind, and speed, wind direction, rider position, and who-knows-what-all can affect the airflow around the filters. This can raise hell with jetting specs and make tuning a real PIA. Getting it jetted right in first gear might mean it is jetted too rich at 70 mph when there's a low pressure zone diectly behind the cylinders..... or it could be lean because a different shape or leg positon can funnel air to that spot, creating a high pressure zone right there.....

Try 'em if you like, but do like Tech says and hang onto the stock airbox like the gold it very well might be.

The bike is fully-faired. Is airflow still a possible problem? I'd sure like to know before dropping $150 on a set of K&N pods.

Fully-faired may or may not make a difference.... your best bet(no guarantee) is to talk to as many other Kat owners who have tryed pods and see if they had any problems jetting them after the switch. Most of the time, pods are more hassle than they are worth, as far as simplicity and rideablity are concerned.

BuzZz wrote:Fully-faired may or may not make a difference.... your best bet(no guarantee) is to talk to as many other Kat owners who have tryed pods and see if they had any problems jetting them after the switch. Most of the time, pods are more hassle than they are worth, as far as simplicity and rideablity are concerned.

Hey, thanks for staying up so late and taking care of me.

I've just been on a wild internet goose-chase to find a large forum of Katana riders with plenty of tech stuff, I'll poke around there.

For now I will skip out on the pod filters and just get the necessary o-rings for getting my bike possibly running this season.