Topic: Am I flooding my bike??? 77 750F

[Lumbee]

77 CB750F...continuing saga...

...as per other posts, I just brought this bike back to life and am working out the kinks.  Todays issue is I think I'm flooding the bike when starting it.  The bike seems to start hard (don't all these bikes  ) However the last couple times I started it instead of pulling the choke I notice if I just turn the thumb screw on the carbs a rotation or two, it fires off much easier and "wants" to start more readily than if I pull the choke.  When I pull the choke its like I don't get any sputtering til I almost run the battery (or my right leg) down.  A few weeks back I adjusted the set screw on the carbs to apply more throttle when the choke is on, and I wonder if that is flooding the bike making it hard to start.

...any and all comments welcome...

[hcritz]

Hey Oh Great One!
Had all sorts of trouble starting my 77 when it was cold...finally found the magic combination for mine and now it fires instantly.
Mine is completely stock except for the exhaust which are 4-2...I suspect that they are very similar in backpressure to stock ones as the noise level is about as stock.
When it's cold out...I pull the choke ALL the way out and open the throttle about half way...fires as soon as you touch the button...doesn't take quite as much throttle when it warmer outside...
I have to mind the revs...I think I remember reading somewhere here to keep the RPMs below 4000 when cold to avoid ring breakage.
Until I figured it out...would run the battery down almost before it would start. Just kept trying things till I found the right combo.
With different mods and jettings etc...they may all be different...

[Lumbee]

hmm...I suspect that won't work for me, but I'll give it a whirl next time I start it...never know...

[hcritz]

Mine may be a bit rich...as it runs well cold...with the choke partially out...I can ride away after just a very brief warmup.
After about a min...I can push the choke in and it runs and Idles fine...
Haven't pulled the plugs since I put the new ones in...they have about 700 miles on them now...Need to do that and see what they look like...

[Lumbee]

...what r u jetted at...stock jetting for the F was 105, which is what I'm jetted at, so I can't beleive I'm rich...in fact I was thinking of going up to 110's due to popping on decel...

[hcritz]

I haven't checked the jets...runs too good to fool with!!! Seems I don't have some if carb maladies that many have.
I do want to check the float levels...when I got the bike one of the floats was installed upside down! So NO fuel was getting in the bowl...so it was running on three...took me a bit to figure out that...ran pretty smoot even on three...just now much power.
Fixed that and WOW!
Could be you Idle mixtures are a bit rich...the extra fuel in the exhaust could cause the popping on decel.

[MetalHead550]

Im not experienced with 750's.....yet! (one o these days  ) but the same may apply.  On my 78 550k, when you pull the choke nob it of course closes the choke through linkage BUT it also opens the throttle slightly to essentially do what you are doing when you turn idle set screw.  On my 75 550 however, pulling the choke ONLY activates the choke and when starting I crack the throttle slightly for the same effect.  On the 550's that modification to the choke, where it auto opens the throttle, occured at the 77 model year.  If its the same for the 750's, you may find that your choke is supposed to open your throttle a bit too, and the linkage which does so may be out of adjustment. 

[hcritz]

Hey MetalHead!
My 77 does have the fast idle on the choke...as soon as it starts I ease the choke back in until it idles at 2000...runs smooth there and I can push the choke all the way down in about a min...brings it back to a nice 1000 rpm idle...
Could be that's not working on the The Great One's bike...
I still have to open the throttle a bit to get the initial start...