Author Topic: need opinions on carbs  (Read 1213 times)

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Offline hapakev

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need opinions on carbs
« on: January 18, 2010, 01:50:57 PM »
Which are the best cb750 carbs and why?
Smoking Jack
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Offline GammaFlat

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Re: need opinions on carbs
« Reply #1 on: January 18, 2010, 01:53:40 PM »
K6
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Offline gerhed

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Re: need opinions on carbs
« Reply #2 on: January 18, 2010, 02:58:45 PM »
These are cool:(http://www.cyclexchange.net/Carb%20System%20Comp%20Page.htm)


I have a set of these on my '75 750F
--work well ---fit very close to the frame, though.
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Offline hapakev

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Re: need opinions on carbs
« Reply #3 on: January 18, 2010, 03:43:13 PM »
I meant stock carbsd, but those are sweet. Someone posted that those won't fit on a stock frame. I was bummed when I read that as I was planning on using them. What about stock carbs, which year is best?
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline wannabridin

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Re: need opinions on carbs
« Reply #4 on: January 18, 2010, 03:53:35 PM »
i've heard F2 carbs are some of the best performing.  but i've also heard the K carbs do a good job as well...
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...

Offline hapakev

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Re: need opinions on carbs
« Reply #5 on: January 18, 2010, 04:03:15 PM »
I have a 73 motor I am rebuilding, thanks to Ricky Racer, and was wondering if I should use my 78F carbs or try to find some earlier ones?
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline hapakev

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Re: need opinions on carbs
« Reply #6 on: January 18, 2010, 07:37:30 PM »
Wow!! No more opinions? Where is everybody?
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline wannabridin

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Re: need opinions on carbs
« Reply #7 on: January 18, 2010, 07:49:40 PM »
Wow!! No more opinions? Where is everybody?

you have to remember that some of the big ones on here are on the other side of the world, so responses come later than you want.  the others that are close by usually own shops, so they're busy too...

MReick should be able to chime in here, same with MC and Terry, they always have great advice!
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...

Offline hapakev

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Re: need opinions on carbs
« Reply #8 on: January 19, 2010, 08:56:52 AM »
you're right of course, I can wait for the wisdom :)
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline fmctm1sw

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Re: need opinions on carbs
« Reply #9 on: January 19, 2010, 09:20:38 AM »
Wow!! No more opinions? Where is everybody?

Contrary to popular belief, not everybody here has a 750  :)

regards,
the pouting guy that wants one...
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Offline tinyrobot

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Re: need opinions on carbs
« Reply #10 on: January 19, 2010, 09:27:43 AM »
The lack of responses could be because of the question too.  "Best" carbs for a 750.  Almost an oil thread.  Best for what: cost, parts availability, performance, function, aesthetics, rarity...?

Offline gane

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Re: need opinions on carbs
« Reply #11 on: January 19, 2010, 07:17:50 PM »
My 2cents,  Sohc 750's are unique in their spacing & intake throat diameters. Early 750 carbs were cable operated (4 cables) & were never really right at both initial opening & full opening, & were / are in constant flux...  late 71-thru 76, while not the optimum carb have some nice attributes, (hold sync nicely, drop off bowls, brutaly simple in design etc.)  77-79's K &F carbs  can be fit w/ corresponding intake manifolds, and step-up to 28mm, w/acc. pumps.  and when right are better.. Unfortunatly due to the acc. pumps design, inaccesible check valves, & pressed pilots are harder to get "right". For 836 & larger, 29mm Mikuni "smoothbores"  were excellent, but required special manifolds,  rare & expensive... Yamaha seca/maxim 650/750 cv's can be "persuaded" to fit, But to date, have'nt been able to match stocker's  overall ridability..undoubtably there are many options, just my experiance...Luck G

Offline Flying J

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Re: need opinions on carbs
« Reply #12 on: January 19, 2010, 07:23:04 PM »
PD carbs (77-78) have a accelerator pump. That is what i would say makes them better then the rest.

Offline Spanner 1

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Re: need opinions on carbs
« Reply #13 on: January 19, 2010, 07:29:21 PM »
A '73 motor deserves '73 carbs but you might prefer the later 'pumper' carbs for their extra throttle response. More stuff to go wrong in the later carbs tho'..!
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline hapakev

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Re: need opinions on carbs
« Reply #14 on: January 20, 2010, 08:37:02 AM »
Thanks for the comments.  I think I will stick with my PD carbs.  Sounds like they are the most advanced of the stock carbs, and work well when they are clean.  Since I already have a set, I may as well rebuild them. 
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline wannabridin

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Re: need opinions on carbs
« Reply #15 on: January 20, 2010, 11:50:14 AM »
pictures for those that can't distinguish the years and models of carbs??  what is a PD carb?
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...

Offline Yoshi823

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Re: need opinions on carbs
« Reply #16 on: January 21, 2010, 05:09:52 AM »
I got the OEM carbs on my 750F2 working well with K&N individuals on them. I had the carbs in bits to be painted, fitted 750K7 mains (118s in the UK), float bowls raised 1mm, inlets polished to match K&Ns for flow.Got good MPG & good throttle response with the needles in the 3rd notch with small shims under so'e to get the best between 3rd & 4th notch.
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Offline hapakev

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Re: need opinions on carbs
« Reply #17 on: January 21, 2010, 09:04:19 AM »
Did the F@ carbs overthere have adjustable needles?  The needles on those carbs here in US are fixed height.  I have heard of some shimming the needles here, but I wish they had the clips.

Wannab- the PD carbs are the 77-78 carbs.  I dont have a pic right now.
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline Flying J

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Re: need opinions on carbs
« Reply #18 on: January 21, 2010, 10:57:30 AM »
I have a set of 77 and 78. the 77s are adjustable and the 78 are not. I swapped out the needles and had all kinds of problems, so i changed back. Not sure if they were messed up or what. I shimmed my 78 needles but its hard to find the correct washers. I found them online at a carb shop.