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Air/fuel mixture screws 82' Katana 1100

  • Thread starter Thread starter Anonymous
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Anonymous

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Does anyone know what the air/fuel mixture screw settings should be for a 1982 1100 Katana. I finally got hold of a Haynes manual for it but all it says about the air/fuel screws is that it's factory preset and must not be disturbed. That doesn't help me much if the previous owner has disturbed it. How many turns out should it be?
 
There is no pre-determined setting for the pilots or air screws on ANY
carbs. They are set at the factory using an emissions analyzer. There are internal differences in each cylinder that effects combustion. These screws are the "fine tuning" the factory uses to get each cylinder within spec'.
If you could compare all 4 carbs on a new bike, you may find that each one was adjusted differently.
If you want a "ballpark" guess, I would guess they are about 2 turns out from the factory. You have the CV carbs. My experience with the VM carbs
is that the pilots are generally 3/4 to 2 turns out and the air screws are generally 3/4 to 2 1/2 turns out. With the VM carbs, it's easy to adjust the air screws. You adjust them to achieve the highest idle and then re-adjust the throttle stop knob. I'm not sure if this method works for the CV carbs.
I believe they have 1 screw, the pilot, or what some call the mixture screw. When it's adjusted out, the AMOUNT of mixture is increased, not just the fuel or air.
 
I have a spare set of the CVs sitting on my bench, along with the standard VM26s and some Z-1 carbs..

The CVs have the one screw on the outlet of the pilot circuit. Screwing out should be like opeing the throttle, more fuel/air mix. The air jet and pilot jet control what the mixture is.

I am just going through setting up some carbs after many years of not touching them..so now I am back in the real world!!!
 
I also have a 1998 Suzuki Bandit with 34mm Mikuni CV carbs and the a/f screws are a big part of tuning the carbs. The adjutment is done by opening up the a/f screws and turning them in until the idle drops or stumbles and then back out 1/4 turn or so but I was wondering what the baseline settings were. I know the Bandit came from the factory with the a/f screws 1 3/4 to 2 turns out but after installing a jet kit and K&N's, they're at 3 1/2 turns out now.
 
Well if it makes you feel any better, my 82-1100, 34 mm Mik. CVs with KN pods, Dynojet jets and needles, depending on the carb in question, runs between 2 3/4- 3 1/4 turns out, roughly at sea level
 
I picked the bike up used this summer as a winter project and the a/f screws are 3 1/2 turns out which seemd excessive. I haven't spent much time tuning it yet because it's going to get a good overhaul this winter. I alos mentioned earlier that the Bandit had 34mm CV carbs, but it acutally has 36mm carbs. Not that it has any relevence to this but I thought I'd correct myself before someone else did.

Thanks daveo. I'll start off by turning the screws in a little.
 
CDNBandit said:
I picked the bike up used this summer as a winter project and the a/f screws are 3 1/2 turns out which seemd excessive
Thanks daveo. I'll start off by turning the screws in a little.
Click to expand...

Don't necessarily just go by a set number, adjust to where that particular cylinder likes it, however many turns, just use that as a ballpark.The advice about turning in till it roughens,then open 1/4, is good. The 'sweet spot' on the overall AF mix adj., as opposed to a 'just air' or 'just fuel' adj. is much more vague feeling. My outer 1-4 cylinders like it a little richer than the inboard 2-3, an EG analyzer would be really nice for this
 
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