carb syncing.... ?'s

[340frontporch]

finally fired teh bike back up... have a few questions. bike idles wayyyyyy to high. lowered the clip on the needle. main is one up from stock (can't remember the number) and pilot one up as well. can't get teh bike to idle low enough. didn't mess with the air idle screw as i figured the problem was way to much fule going in and not an air problem. running open exaust and pod filty's. today after work, lowered the needle back down as well as puttin the pilot back to stock. now can't get the bike to start.... ps no choke so i screw the throttle idle in to start.... ideas? should i go back to what would get the bike to start and screw with the air idle screw?

 

[340frontporch]

also... the right cylinder is ALOT quiter than the left. and a ton of backfire out hte exhaust (fuel burning off after spark)... am planning on replacing the coils/condenser to see f that makes things fire off better...?

 

[5twins]

Just a couple questions so I can maybe understand your questions better ..... what does "teh", "fule", and "filty's" mean? Is this some secret language used by today's texting youth? Should I understand this jibberish and if so, I'm sorry that I don't. And I can't help until I do. What I can tell you is there is no "air" screw on the 650 carbs so don't feel bad that you can't adjust it, none of us can because it's not there, lol.

 

[340frontporch]

teh would be the mispelled, fule would be fuel misspelled and filty's would be lazy for filters. and pilot screw was what i meat i guess.....

 

[5twins]

If it's a '76 or newer (you need to tell us the year) then your carbs are probably out of sync.

 

[340frontporch]

well the carbs are from a 76 i believe. the frames a 75 motor is a 76. what would i need to sync up? is it the butterfly? theres not center throttle stop screw. ut i can't get it to idle low enough.... but the right cylinder seems to hardly fire is my assumption as to why if back fire outta the exhaust like a s.o.b.

 

[XSLeo]

If there is no center sync screw then the carbs are 75 or older. Do you have a repair manual? The Clymer, page 22 paragraph 2 tells how to sync the carbs on the 75 and older bikes.
If you go to Mike's he has pics of carbs to help identify your carbs.

 

[340frontporch]

judging by mikesxs site they are 76's. i'm thinking the center screw just hasn't been there and i just assumed that it never was. guess the po lost is or something. i've been reading and am still unsure as what "syncing" means to do. i.e. what is getting synced up via what. am i syncing the opening of the butterfly to one another via the idle screws, assuming i am to have two? am i supposed to be syncing the slides? and how the crap would i go about that as they operate (to my knowledge) on vaccuum, which would make it hard to sync those if the carbs are off the bike.... please help... i think i'm becoming more stupid by the minute.....

 

[XSLeo]

On the 76 carbs you set the idle speed with the screw on the left side. The syncing is to get the right carb running the same as the left. This is done with the sync screw between the carbs. The sync screw adjusts the right throttle plate to the same amount of opening at idle.
A properly synced set of carbs gets both cylinders running the same. If the sync is off on cylinder trys to run stronger and faster than the other. This unsync causes the engine to run with more vibrations.
By syncing the throttle plates each cylinder has equal vaccum. This equal vaccum syncs the slides. With matching vaccum the slides will lift at the same time and rate of opening.
On the sync mechanism the left side carb has a single blade coming off the throttle shaft. On the right carb it has two blades kinda U shaped. The sync screw screws into the upper blade of the U. On the bottom blade of the U there should be a spring loaded plunger. The single blade of the left carb fits between the screw and the plunger. The screw does the adjusting and the plunger keeps the blade pushed against the screw.
If the screw is missing, is the plunger? If they are about the only place you might find them are from another set of carbs.
Here's a pic of what yours should look like.