pilot air screw ?

[M3RL1N]

hi guys
just checkin with you. but. im adjusting the mixture screws because 2 of my plugs are sooty. am i right in thinking that i turn the screw clockwise to make the mixture more lean? and anticlockwise to richen it?

thanks

regards
Dave

 

[M3RL1N]

ahh

ahh

ahh that seems to conflick with something ive just read in this section .
heres a copy/paste of it

Those are "idle mixture adjustment screws" and control how much of a mixture is admitted to the cylinder. If you reference the picture that BassCliff posted, you can see that the pilot air jet and the pilot fuel jet produce a mixture that is admitted to the airstream in three places. Two are on either side of the closed throttle plate. The third location is controlled by the adjustment screw. Turning the screw OUT (counterclockwise) will richen the idle mixture, turning it IN (clockwise) will lean it.

are idle mixture adj screws the same thing as pilot air screws?

regards
Dave

 

[M3RL1N]

lol sorry chuck hahn not that i dont belive you . just that ive been messin aroiund with them for a while now on the assumption that opening anticlockwise was allowing more air in (as you said) but dont seem to be able to get enough air in there to get rid of the sooty plug problem. so i was seeking a second opinion. (and you gave one.Thank you)

oh and thanks for your time replying.

regards
Dave

someone removed the post i was reffering to. now i look like im a nutter......im not honest

 

[chuck hahn]

here read these....http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf
http://www.mtsac.edu/%7Ecliff/storage/gs/mc_maint/GS_CV_Carb_Cleaning_Series.pdf

 

[chuck hahn]

The very last line in the VM tutorial states the following "If you have trouble with re starting and low speed riding .........turn the SIDE AIR SCREW OUT ( leaner)........

 

[M3RL1N]

thanks

thanks

thanks ill give them a read now..it was a quote by steve in another post that had me thinking differently. the one i quoted on my post . i think reading and experimenting is in order


thanks again
regards
Dave

 

[chuckycheese]

Year

Year

thanks ill give them a read now..it was a quote by steve in another post that had me thinking differently. the one i quoted on my post . i think reading and experimenting is in order


thanks again
regards
Dave

Dave, I think you'll find it helpful if you add the model year your bike is to your signature line. (I'm guessing that you don't have VM carbs.)

 

[chuck hahn]

The sooty will not go away from all the turning in the world of the air screw if the main jet, pilot jet, neddle jet arent correct for your engine size and the type of exhaust you are running. If you read my thread CARB MECHANIC WANTED you will see i just went thru then exact sme thing on my 77 750. I fought all they were trying to tell me till when i opened the carbs and the guys and me finally realised the jetting was all wrong. I was confused on what needle did what as well.

 

[chuck hahn]

what year is the 550? stock exhaust? pods or stock airbox?

 

[M3RL1N]

its an 82 ex or ez stock exhaust and replaced stock air box.

i think ive found the reason i was confused though ..i have cv carbs and found this suppliment to it on basscliffs site..

Bill Kingston has brought it to our attention that the references to a Pilot Air Screw may be incorrect. He states that on these carbs use a Fuel Flow Screw instead. This means that you are controlling fuel running through the passages with this adjustment, not air. So when turning the screw counterclockwise you are increasing fuel flow and when you turn it clockwise you decrease fuel flow.

its night here now but ill read up tonight and experiment tomorrow.
im not sure if i have the original engine,so sometimes its confusing

regards
Dave

 

[chuckycheese]

Right

Right

its an 82 ex or ez stock exhaust and replaced stock air box.

i think ive found the reason i was confused though ..i have cv carbs and found this suppliment to it on basscliffs site..

Bill Kingston has brought it to our attention that the references to a Pilot Air Screw may be incorrect. He states that on these carbs use a Fuel Flow Screw instead. This means that you are controlling fuel running through the passages with this adjustment, not air. So when turning the screw counterclockwise you are increasing fuel flow and when you turn it clockwise you decrease fuel flow.

its night here now but ill read up tonight and experiment tomorrow.
im not sure if i have the original engine,so sometimes its confusing

regards
Dave

Now you've got it figured out!:clap: (Be sure to add your model year.)

 

[chuck hahn]

Thats why i posted both tutorials..i dint know which style carbs you had or year or what not..so i thought youd find what you were looking for at eihter one!! Oh and yes, plz add the year of your bike to the size there.. helps at a glance to know what we are talking about..

 

[M3RL1N]

chuckycheese done that now thanks

regards
Dave

 

[chuck hahn]

right on the front of the engine where the upper half and the bottom half are joined ( just below the # 1 exhaust pipe area) youll see a little flat spot on the seams of the two casings..theres a number there with the size of the engine. It should say something like 548cc or something close to 550 anyways.

 

[chuck hahn]

Sorry if i had added to the confusion when i posted the quote from the VM tutorial..I am used to all my bikes being VM and i unfairly went there on auto pilot. The proper thing should have been to ask you what type of carbs they were..sorry, my bad!!

 

[M3RL1N]

my bad too i should have said which carbs i had....now i know i was reading info for two different sets of carbs.. a case of info overload.

regards
Dave

 

[chuck hahn]

OH YEAHHHH..i was going absolutely feaking BALLISTIC with all the crap just the other week. I was so pizzed that at one point i grabbed a 2 lb sledge and was almost about to bash the bike to death. When you read all kinds of stuff and are stressed it all runs together and your not receptive to anything and you second guess youreslf as well..I get it!!!

 

[Steve]

Now, let's add a little more confusion to clear up the previous mis-quotes.

My previous statement still holds true for your carbs. THOSE ARE IDLE MIXTURE ADJUSTMENT SCREWS.
They are not "air screws", they are not "fuel screws", they are MIXTURE SCREWS.
They will adjust how much of a pre-set mixture is admitted to the cylinders.
The mixture is pre-set by the pilot air jet in the intake throat and the pilot fuel jet, down by the main jet in the bottom of the carb.
As Chuck mentioned, though, you DO have to have the correct jets to set the correct mixture.
You then use the MIXTURE SCREWS to adjust how much is used.

Turning them clockwise will lean your mixture, turning them anti-clockwise will richen it.


On the earlier VM carbs (the ones you DON'T have), there are separate screws to adjust the mixture, so they do have "pilot air screws" and "pilot fuel screws".
On the BS-series carbs, like yours (also known as "CV carbs"), there is only the MIXTURE SCREW.

If the bike has been running (maybe poorly, but running), turn all the mixture screws in carefully until they seat lightly.
Back them out 2.5 turns to start with. Warm up the bike, turn each screw in until you hear the engine start to slow down a bit,
then turn it back out about 1/8 turn, go to the next screw. That should clear up your problem.

.

 

[chuck hahn]

Steve..he clarified that as he said he was reading info for BOTH styles of carbs and it was blending together and causing the mix up.....

 

[M3RL1N]

thanks guys. i think i'm clear now and as soon as i get chance i think i have the right info.

"Turning them clockwise will lean your mixture, turning them anti-clockwise will richen it."

thats the bit of info i was missing.i then read 4 or 5 tutorials and confused myself stupid
i was looking for the standard settings in manuals with cv carbs as to how many turns out, and all i could find apart from "preset" was 3 1/2 turns out, which left me with 1 and 2 plugs clean and 3 and 4 sooty,turning the screw anticlockwise to let more air in was not helping,but neither was anything else i tried, so i kept going back to 3 1/2 turns out (going round in circles)

going to start at 2.5 turns out and go clockwise as soon as i get chance.and just to clarify everything else has been done to the carbs over the last 2 months.leaving the original jets in and replacing o-rings gaskets and such other than tick-over they are running superb. and bike pulls like a demon.

thanks again for your help guys.and sorry i caused more confusion.

regards
Dave