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77 CB750F Rebuild/Replace?

ROCCITYCB

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Well I hope I'm not beating a dead horse here, but my question is a little off of what I have found on the forum so far....

I recently purchased a 77CB 750F2, the bike came with pod filters and a 4-1 exhaust... after some diligent work in attempting to get the carbs in tune with one another, we cannot get the 1st carb to tune at all... it is leaking fuel as well.. additionally on the 3rd carb the A/F screw barely threads in, to the point I cannot adjust it at all... with that being said, would you recommend I have the carbs rebuilt OR purchase new ones..

In reference to purchasing new carbs, i have heard that going with aftermarket Mikuni or Kehin carbs are not beneficial by some people, and some swear by them... As well as pod filters on the 77 cb750 are worse than the airbox and vice versa.. which I do not have...

Ultimately I am hoping to run the same set up, with the 4-1 exhaust and pod filters, so I do not have to buy additional parts and make what I have work... Could this be as simple as rebuilding the carbs and properly jetting them accordingly? or would the "race" carbs by Mikuni be another good option? Thanks for any insight!
 
I've got my PD42's (77-78 keyhole style carbs) tuned to my pods and 4 into 2's. It took a while and a total of 6 dismantling and reassembling of my carbs, but now I wouldn't change 'em out for anything. That said, I don't know what's wrong with your carbs. The thing about the A/F screw not threading in would have me worried, but a fuel leak on carb 1 could be an easy fix (float height, float needle, o-rings, gaskets).

If they were mine, I'd look inte how to get that A/F screw thread thingy fixed. It could be a jammed o-ring up in there, or a stuck washer (that's what's on the tip of the A/F screw - take one out from another carb to see what to look for). If that works out I'd rebuild 'em and run 'em. Tuning is part of life with these old scoots, but when done right, just keep 'em clean and ride your ass off!

Maybe someone else have any better input. This is just my .02
 
Oh - and if you decide to run these carbs, make sure you get your acc-pump squeeky clean. That's mandatory to get these to run right.
 
I've got my PD42's (77-78 keyhole style carbs) tuned to my pods and 4 into 2's. It took a while and a total of 6 dismantling and reassembling of my carbs, but now I wouldn't change 'em out for anything. That said, I don't know what's wrong with your carbs. The thing about the A/F screw not threading in would have me worried, but a fuel leak on carb 1 could be an easy fix (float height, float needle, o-rings, gaskets).

If they were mine, I'd look inte how to get that A/F screw thread thingy fixed. It could be a jammed o-ring up in there, or a stuck washer (that's what's on the tip of the A/F screw - take one out from another carb to see what to look for). If that works out I'd rebuild 'em and run 'em. Tuning is part of life with these old scoots, but when done right, just keep 'em clean and ride your ass off!

Maybe someone else have any better input. This is just my .02

None of the A/F Screws have any o-rings or washers on them... we tried to the other 3 screws in carb #3 and none of them would screw in, so its unfortunately screwed up threads or something blocking it :/
 
Oh and im looking at the easiest fix possible, if that means new carbs id rather go that route, just wanna make sure if i do run Mikuni's or something similar, that i get the bike running properly.... will the bike run 100% if tuned properly with aftermarket carbs?
 
As long as the carbs fit 100% and you get them tuned right and the throttle cable fits AND you have the $ then you'd be fine with any carbs.
I've read about guys running Kaw1000 carbs with little hazzle. New boots and proper jetting..

Look into what a set of good working used CB750 sohc carbs would set you back. If you get a good set of PD42s you wouldn't have to chase down new boots and cable. Probably just jets.
But if you're dead set on Mikunis, that could probably be made possible as well. I don't have any experience on that though.
 
As long as the carbs fit 100% and you get them tuned right and the throttle cable fits AND you have the $ then you'd be fine with any carbs.
I've read about guys running Kaw1000 carbs with little hazzle. New boots and proper jetting..

Look into what a set of good working used CB750 sohc carbs would set you back. If you get a good set of PD42s you wouldn't have to chase down new boots and cable. Probably just jets.
But if you're dead set on Mikunis, that could probably be made possible as well. I don't have any experience on that though.

This is what I was thinking....

http://www.dimecitycycles.com/vinta...750-sidedraft-racing-carburetor-016-3027.html
 
i have a nice set of f carbs for a 77-78 cb750 that need a new home there in good shape just need a good clean pm sent
 
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