I have a 98 Banshee with ported/polished, bored, coolhead with 18cc domes, etc., for an engine.

I just purchased a set of 35mm Keihnn Air Strykers and had them polished before installation (by the way, they look awesome polished!!!).

My question is this, there are two screws on each carb. The larger, plastic screw is the idle speed adjustment. The smaller, brass screw I am assuming is for the idle mixture adjustment.

Is this smaller, brass screw the idle mixture screw? What is it for? Does it only affect the idle? Can I damage anything if they are improperly adjusted?

More importantly, how many turns out should I adust them to? Do I turn them exactly the same number of turns out?

Any help would be very much appreciated!

 

Wow, those 35mm POLISHED carbs REALLY sound impressive, rob4092!

I bet you're the envy of every citizen of "Rocky Pointe," Mexico, with those jewels!

Good luck with those screw thingies.

Tree Farmer

 

Treefarmer:

Please find somewhere else to belittle others.

If you are not interested in a topic another member writes about, just move onto the next until you find something that interests you.

Shame on you for taking advantage of something that doesn't cost you a single red cent, but is enjoyed by thousands who have one thing in common; Great conversation about ATV'ing.

Your comments are not appreciated, welcomed, nor good for the ATV Connection!

 

I would still really appreciate any help to my original questions.

Thanks!

 

You're absolutely right, rob4092; no offense intended.

I wonder, maybe whoever sold you the carburetors might have some suggestions for starting points for the screw postitions. Also, the guy who polished them, or the guy who installed them, might have noticed whether the brass screw was a mixture screw or not.

Enjoy those new carbs and please disregard my levity.

Tree Farmer

 

Hey, Tree Farmer,

You made a mistake but you showed some class too! Good job!

 

Meanwhile, back at the batcave..... Rob is still wondering about those screw thingies.

I am not familiar with those carbs, but in general, the small brass screws should be your idle mixture screw. They are I believe, also known as air screws because they change the mount of air going through the idle circuit.

Anyway, turning them out leans the idle mixture and in richens the mixture. On average around 2 turns out is normal, but experiment. What you want to do is get your quad warmed up and idling reliable then start turning the idle screws out and note the increase in idle speed due to the lean mixture. The idle speed will peak, and if you keep turning the engine will run unevenly then die. You want to be right around that peak; this gives you a fairly lean idle. If your quad stumbles off idle try adjusting 1/8 to 1/4 turn either way of that peak and see if that helps. Both screws should be the same number of turns out. I hope this helps. Also, adjust the idle speed *****/screws/thingies to get the same throttle slide height, adjust these the same amount as well. A vacuum guage type tool is best for syncronizing your carbs. It shows the vacuum on each and you adjust so that both are even.

Good Luck.

 

Good points, WyoRider; however . . .

Like you, I'm unfamiliar with the design of these carbs. Adjustment of the mixture screws depends upon their location, I'm told.

If the screws are on the air intake side, they control the amount of air in the mixture; if on the engine side, they control the amount of fuel entering the mixture. Thus, a counterclockwise twist "leans" the misture, if the screws are upstream; a counterclockwise twist "richens" the mixture, if the screws are on the downstream side.

Your tuning procedures look good to me; a good-faith response to a sincere question.

Tree Farmer

 

rob4092,
I have to agree with Tree Farmer's interpretation and unless someone else more knowledgible responds, I'd try 2 turns out from seated, and test from there as to idle or just off of idle. Since the idle adjustment is basically a means to tweak the performance of the pilot jet, it makes only a very slight difference in overall performance, mostly in eliminating a stumble just off idle.

 

My hats off to all who responded!

Thanks, you have given me several things to think about and attempt!

Anyone else have experience with these carbs?

And Tree Farmer, thanks for the feedback! No harm, no foul!