Author Topic: 750f needs new carbs, any year work?  (Read 1368 times)

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Offline OApb

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750f needs new carbs, any year work?
« on: August 31, 2009, 09:01:07 pm »
Hey guys, while going through my carbs that I was told were "professionally rebuilt" Ive noticed things that are making me a little angry. Can any year 750 carbs work? Bike is a 78 750f. Thanks

Offline TwoTired

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Re: 750f needs new carbs, any year work?
« Reply #1 on: August 31, 2009, 09:33:15 pm »
I suppose any carb can be made to work.  But, only the 77 and 78 F model carbs are a direct replacement.  Anything else, and other parts have to change as well.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Slayer

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Re: 750f needs new carbs, any year work?
« Reply #2 on: August 31, 2009, 09:57:05 pm »
Whats wrong with them?

Offline OApb

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Re: 750f needs new carbs, any year work?
« Reply #3 on: August 31, 2009, 10:15:06 pm »
couple float bowl screws stripped causing bowls to leak, few other smaller things. mainly just cant get them to run right. I just would like a couple rides this season before i tear her down and convert to fuel injection

Offline Slayer

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Re: 750f needs new carbs, any year work?
« Reply #4 on: August 31, 2009, 10:19:46 pm »
If it just a few stripped bolts that can be replaced. You could save yourself some cash and maybe get some riding time in if you fix your carb problem. Once you break it down piece by piece it isn't as bad as you may think.

Offline OApb

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Re: 750f needs new carbs, any year work?
« Reply #5 on: August 31, 2009, 10:43:01 pm »
i was thinking maybe some longer screws with a nut or 2 would work. cylinder 1 isnt firing like it should. The pipe takes alot longer than the others to get hot. Its got good spark and im pretty sure its not getting fuel like it should. The small plug in the intake side of the carb is missing. is it possible that its letting too much air in and throwing the mixture off alot and causing that issue? ive tried to look up what it is but cannot find any info on it. It looks like just a plug for a hole but i could be wrong. Im really looking forward to the FI conversion so I can get rid of the headache these carbs are giving me

Offline Slayer

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Re: 750f needs new carbs, any year work?
« Reply #6 on: August 31, 2009, 11:02:02 pm »
Yea I am not sure what plugs you are talking about but whatever is missing you have to replace. Everything has an important job in there. That's where I would start. Look at the carb section on here http://www.mediafire.com/?5ttzdg9yyuz 
That may not be your specific bike model but that should be the same set of carbs. Good luck man.

Offline OApb

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Re: 750f needs new carbs, any year work?
« Reply #7 on: August 31, 2009, 11:14:37 pm »
Thanks for that manual. its alot better than my clymer. According to that manual the missing plug is just that. Its the plug for the hole that you screw the vaccuum sync guages to. Im guessing that with that missing #1 cylinder is getting too much air which is causing it to not fire properly. I should prolly find something to put there

Offline Flying J

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Re: 750f needs new carbs, any year work?
« Reply #8 on: September 01, 2009, 07:00:04 am »
Yes, if that plug is gone dont expect your bike to run well at all. That is for doing a carb sync, which you should do if you can. Or at the very least bench sync them. Who told you they were proffesionaly cleaned? I dont trust anybody with used parts. Seeing is believing. Anyway, the other carbs are no better then the 77-78 and they dont have accelerator pumps. If there was any 750 worth owning besides an F im sure Twotired would have at least one.

Offline Slayer

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Re: 750f needs new carbs, any year work?
« Reply #9 on: September 01, 2009, 08:44:24 am »
I would try to find a salvage yard in your area or check out ebay. You might find a parts carb. There are probably lots of people who get frustrated and want to just get rid of those things so they should be around.

Offline Bamboozler

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Re: 750f needs new carbs, any year work?
« Reply #10 on: September 01, 2009, 12:24:43 pm »
Thanks for that manual. its alot better than my clymer. According to that manual the missing plug is just that. Its the plug for the hole that you screw the vaccuum sync guages to. Im guessing that with that missing #1 cylinder is getting too much air which is causing it to not fire properly. I should prolly find something to put there


I have a spare 78F carb set for parts.. If you need one of those plugs PM me and kick one your way.
'78 CB750F Turbo, 101 rwhp @ 8 PSI (Project thread)
2007 Yamaha FZ1
'78 CB750F basket case crying for a resto
'78 XL250S
'78 Suk GS750E
Digital Ignition project (Project thread)

Offline OApb

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Re: 750f needs new carbs, any year work?
« Reply #11 on: September 01, 2009, 05:26:08 pm »
Hey thanks for the offer. I went to lowes and picked up something real close to the plug along with some screws and nuts to replace the stripped ones. If the new plug doesnt work Ill def send you a PM and shoot a couple bucks your way

Offline OApb

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Re: 750f needs new carbs, any year work?
« Reply #12 on: September 01, 2009, 08:28:32 pm »
she runs great!!! that plug missing was definitly the killer. I put the replacement I got for $.27 in and fired her up and she idled way high. I turned the idle down and she purrs like a kitten. It even fixed the problem I was having with cylinder 1(which happened to be the carb with the missing plug) It wasnt firing correctly and that header pipe was taking forever to heat up. It now heats right up. Im glad I didnt decide to scrap the season and start my build. I might just be able to get some riding on her before the snow flies(which is always right around the corner here in buffalo :) )

Offline Slayer

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Re: 750f needs new carbs, any year work?
« Reply #13 on: September 02, 2009, 12:16:20 pm »
Good to hear. Actually I am a little bit jealous haha.