Topic: POS carbs???

[dave the welder]

ok here we go.1978 ALL STOCK 2000 miles.will not rev up.starts and idles great with the choke on.open the throttle a little and it will rev a little then starts to die.release throttle and it idles great.i have had the carbs apart 3 times and as far as I know every passage is clear.the points are set at .014,the timing is spot on and the spark advance is working also.i know its fuel related because when its trying to rev up and starts to die I can squirt a little carb cleaner in the carb throats and is revs up great.if I had another set of round tops I would swap them but I don't and because of the low miles I want to keep this one original  HELP PLEASE

[raymond10078]

Did you remove the emulsion tubes?  While they are press in, they can be removed.

Air cleaner ok?   Critters and bugs can make their home in there really cause problems.  While you think every orifice and pathway is open, I bet something was missed.

[raymond10078]

Since he posted in the hondamatic section - seemed safe to assume a 750A.

Anyway - the accelerator pump circuit won't prevent you from revving up the engine - it will just stumble a bit when you whack the throttle open.  Regardless, that circuit should be clean, too.

As for the accelerator pump - does each of the pump squirter tubes - spray a jet of fuel when you open the throttle?  You can only see this with the rear of the carbs exposed - or having the carbs off - but full of fuel.  Just asking - not related to your problem - but should work correctly, none-the-less.

[dave the welder]

accelerator pump is working nice stream.air filter is off bike(its clean with a new filter in it)emulsion tubes?are those right next to where the main jets are?if so I carefully removed them flushed them with carb cleaner blew out with air they are clean.also flushed idle circuit.mix screws are out 1 full turn.also the passion for this bike is not there just wanted to keep this one as stock as possible.figured it might be worth more if I go to sell it.my 77 750A that I ride a lot is the one I mess with.i already swapped out the carbs for round tops and just swapped in a mid 70's 750 K cam.its a lot more fun to ride this way

[seanbarney41]

Hi Dave, I would double, triple, quadruple check your intake rubbers.  I am not exactly sure why, but the pd style intake rubbers don't seem to withstand as much adversity as the round top ones, which really sucks 'cuz oem ones are NLA and repros are close to $100 a set.  It seems like a old, hard round top intake boot can still be made to seal whereas the pd ones won't.

[dave the welder]

ok her we go again checked and double checked boots they are soft. clamps tighten without bottoming out on themselves.readjusted mix screws to 1 1/2 turns out instead of 1 turn. now it idles when warm and choke wide open.it still will not rev up. if I put my hand over intake to choke it(richen mixture)it will rev up.as soon as I remove my hand it tries to die . if I spray carb cleaner in the carbs while trying to rev it up it will speed up quite well. so what am I missing???as far as I can tell everything is clean inside. i have read here that these bikes came very lean from the factory but something is still wrong

[Stev-o]

Sounds like it's lean if it likes choke.  What exhaust do you have and what size main jets?

[dave the welder]

all stock. what ever they put in is still there

[xntrik]

Ever figure this out?


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[dave the welder]

nope to many other things going on

thinking maybe just sell it let some one else mess with it