A/F Screw

[zexus]

I was checking to make sure my a/f screws were all correct and discovered that one of them only has about 1/4 of a turn play in it. For some reason is seems to be stuck there. Any ideas about how to fix that? I was thinking of pulling the carbs this winter and cleaning them all up...maybe even doing a little upgrade. Any suggestions on what would be of benefit to the carbs on a stock engine? Thanks.

 

[mr.maxx]

spray a lil break away or similar penetrating oil there.....let it soak for a spell.....then get a proper fitting screw driver and carefully work it back n forth.....adding more oil ......it will come out...just take yer time.

 

[tugla]

+ 1 be gentile with it, lots of oil, pb blaster, aerokroil, similar stuff......good fit driver is the key also

 

[naughtyG]

The best thing to do to carbs on a stock motor is to make sure they're squeaky clean (no gunk anywhere, esp. in the small passages) and check that all rubber parts (diaphragms, coasting enrichners, o-rings, seals, needle valves tips) are all in tip-top condition.

Oh, and a GREAT upgrade if you're gonna tear into them is to swap those crappy Philips screws for Allen head bolts all round, but especially for the fuel bowls and the rack.

 

[zexus]

Okay, thanks guys. Will work that screw with some penetrating oil and a well fit screw driver. I'll leave the carb stock then but give it the cleaning of its life. The bowls already have Allen head bolts as I installed faux velocity stacks, but I will do the same for the rack. Thanks for the advice.

 

[dannymax]

Okay, thanks guys. Will work that screw with some penetrating oil and a well fit screw driver. I'll leave the carb stock then but give it the cleaning of its life. The bowls already have Allen head bolts as I installed faux velocity stacks, but I will do the same for the rack. Thanks for the advice.

V-stacks go on the diaphragm covers zexus, the float chambers are on the other end....allen bolts are handy there also. Don't forget to set your floats while you're there and the reason the A/F screw is bound up is because the spring corrodes and practically welds itself to the inside of the carb body.....almost always on #3 & #4 cylinders. Get some little plugs at the hardware store to seal the holes to eliminate that issue....also some never-seize or the like on the threads.

 

[alorio1]

I would order a new screw now to save on downtime and not put the old one back in............next time it may not come out.

 

[mr.maxx]

I would order a new screw now to save on downtime and not put the old one back in............next time it may not come out.

i agree.....get 2 even...they are only 8 bux each. good to have spares.

 

[zexus]

V-stacks go on the diaphragm covers zexus, the float chambers are on the other end....allen bolts are handy there also. Don't forget to set your floats while you're there and the reason the A/F screw is bound up is because the spring corrodes and practically welds itself to the inside of the carb body.....almost always on #3 & #4 cylinders. Get some little plugs at the hardware store to seal the holes to eliminate that issue....also some never-seize or the like on the threads.

Shows you how much I know about carbs! One of the reasons I want to remove and clean the whole package up is to learn whats what...thanks Will find some plugs to stop it from happening again.

I would order a new screw now to save on downtime and not put the old one back in............next time it may not come out.

That's a good idea, and like dannymax said, a couple would be even better. Thanks.

 

[zexus]

Oh ya one more question. What if I strip the head of the screw? The reason I ask is because I threw some light on the screw and noticed that the head is warn in both directions. If for whatever reason I can't get it out the normal way, is there an alternative?

 

[Dr.n2o]

Oh ya one more question. What if I strip the head of the screw? The reason I ask is because I threw some light on the screw and noticed that the head is warn in both directions. If for whatever reason I can't get it out the normal way, is there an alternative?

Squirt it and wait like the guys were sayin. if it's not mangled you should definitely be able to get it out going back and forth gently with the proper screwdriver. You're playin with brass so take you're time goin back and forth with it. Sounds like you might want to order some screws now. I wouldn't put that one back in. Shine the light in ther while you're workin it and make sure you're screwdriver is dead center.

 

[zexus]

Squirt it and wait like the guys were sayin. if it's not mangled you should definitely be able to get it out going back and forth gently with the proper screwdriver. You're playin with brass so take you're time goin back and forth with it. Sounds like you might want to order some screws now. I wouldn't put that one back in. Shine the light in ther while you're workin it and make sure you're screwdriver is dead center.

Will do. The PB in penetrating as I write this. Already contacted Sean to let him know I'm going to needs some carb parts. Will be pulling the whole carb setup in a few weeks to do a check/clean and replace.

 

[zexus]

Alright my new best friend is PB Penetrating oil. It made short work of the a/f screw. The screw spins freely now. I went to set it the same as the other screws, which is about 2.5 turns. When doing this I noticed that though all the screws are 2.5 turns from the bottom, the newly loosened screw sits at a different depth then the others. I flagged the screwdriver and there seems to be a noticeable difference. If this normal for some screws to be of different depth than others, even though they are the same amount of turns out?

 

[Dr.n2o]

Alright my new best friend is PB Penetrating oil. It made short work of the a/f screw. The screw spins freely now. I went to set it the same as the other screws, which is about 2.5 turns. When doing this I noticed that though all the screws are 2.5 turns from the bottom, the newly loosened screw sits at a different depth then the others. I flagged the screwdriver and there seems to be a noticeable difference. If this normal for some screws to be of different depth than others, even though they are the same amount of turns out?

When I first bought my max many years ago I found one at 1 3/4 out. Other three were 3 out :confused2:....Never hurts to check

 

[m-cman]

It is not normal for the screws to be different depths if at exactly the same settings. There may be some gunk under the problem screw. That is assuming it is sticking up higher than the others. If it lower (not likely) then there may be gunk under the other three. (Again not likely).

 

[alorio1]

The PO may have removed the screw and left the O ring in the hole or washer and O ring in there. Sometimes it hard to detect whether or not the O ring is there and he may have assumed it wasn't and stacked another one on top of it. If thats the case you will have to remove the O ring to properly get the right A/F setting........

 

[zexus]

It is not normal for the screws to be different depths if at exactly the same settings. There may be some gunk under the problem screw. That is assuming it is sticking up higher than the others. If it lower (not likely) then there may be gunk under the other three. (Again not likely).

You may find this hard to believe but it was the other three. After using the penetrating oil on the one screw it must have loosened up some crap build up because when I cleaned up the whole a fair amount of 'crap' was discovered. So after reading your post I figured I'd give the other three a shot of the oil. After turning the screws back and forth a few time and wiping the holes out, sure enough...crap. I then started from scratch and set all four holes at 2.5 turns and then flagged them...and all are now at the same depth...who knew:confused2: Apparently you m-cman. Thanks.

 

[naughtyG]

Bear in mind that the same A/F screw depth *may* not be the right setting! The only way to get each absolutely right is with an O2 sniffer, which'll tell you the A/F ratio. Now, most people don't have one of those (they're usually found on dynos) so we set them at 2.5 turns each as a starting point and go from there.

There are a few methods for finding the right settings such as listening to idle speed change while adjusting (may work well on a single cylinder or even a twin motor but never worked for me on a V4), looking at the spark plugs (white = lean, black = rich, light tan = ok) and generally riding the bike, making small (1/4 turn) adjustments and finding the sweet spot that way.

If any of your A/F screw heads are worn, most defo replace them! You never know when they'll get stuck again and if you strip a head it's a right PITA to get it out. Another good thing to do is to spray a little lubricant in the holes after reassembly (spray grease, WD40, PB) AND find some lil' plastic or rubber caps to close the holes and keep the dirt out.

Someone here found the right size (black plastic) caps a coupla years ago, and I got about 100 or them (minimum order) and distributed them around to forum members. I'm all run out now, but if someone can find the old thread it may be a good idea to get 100 more..