Topic: 750 F ?'s

[78 k550]

Hey All,
750F's did they all have 4 into 1 pipes, so the carbs are tuned for it?
I know on the 550F vs K they used different carbs. Or did they just retune the 750k carbs?

Thank's

Paul

[mick750F]

   Yes, the 750Fs all have stock 4 into 1 pipes. The same carbs as the Ks were used with different jetting. Keep in mind that the '77-'78 750s used different carbs than the earlier bikes.

Mike

[fotoguy79]

   Yes, the 750Fs all have stock 4 into 1 pipes. The same carbs as the Ks were used with different jetting. Keep in mind that the '77-'78 750s used different carbs than the earlier bikes.

Mike

Same carb, but different jetting?  So Are the F series carbs better?  Or are the K series carbs better?  Or are they just simply different?

-Dave

[Steve F]

Carbs are the same, jetting is slightly different.  '77 f's and later used the CV carbs

[eurban]

77 and 78 F and K bikes used slider carburetors with an accelerator pump.  These were not CV carbs.   

[78 k550]

77 and 78 F and K bikes used slider carburetors with an accelerator pump.  These were not CV carbs.   

Which one's are better?

[eurban]

Many people have issues with the 77/78 style carbs due to the added complexity of the acelerator pump, the pressed in idle jets and the need for unscrewing the bowl (the bowl gasket it also more of a PIA to keep in place) rather than the clip system on the earlier carbs.  The main jet needles on the 78s are also in theory not  adjustable (there is only one notch for the clip) however small washers can be used as shims or 77 style needles can be used as a replacement.  Rebuild kits are also a bit more difficult to find . . .The 77/78 carb's  linkages for synchonization are nicely concealed underneath metal caps instead of detiorating rubber and you can drain the bowls easily thru the overflow tubing rather than having to dribble the fuel out of the drain screw (like on the earlier carbs)  From a performance standpoint I would venture to say that when properly adjusted the accelerator pump carbs give a bit more power particularly when you whack open the throttle abruptly.  The 77/78Ks and Fs were strong performers inspite of being heavier than the earlier bikes and it seem likely that some of the performance could be attributed to the pumper carbs.  I pretty much know all the ins and outs of my 78Ks carbs and I have been able to completely rebuild them and fine tune them to my modified motor and intake system. . . . . If all of your experience is with the earlier carbs you may want to stick with them.  Hope this helps