Author Topic: Can you name these mystery carbs?? (Read 6068 times)

Thor's Hammer! · « **on:** July 31, 2009, 08:03:57 PM »

I have a strange set of carbs on my newly acquired 750F.

Pulled the carbs and found they were labeled KEIHIN VE and there was also what looked like a serial # 54AAUKJ...the second A was inside a small square.

This information was on the outside carb on the left side, if mounted on the bike.

Here is the only pic I have at the moment:

I found a set of carbs that look the same on ebay in this auction:

http://cgi.ebay.com/ebaymotors/1993-HONDA-CB750-NIGHTHAWK-CARBURETORS-CB-750-HAWK_W0QQcmdZViewItemQQhashZitem53dbfecac6QQitemZ360173193926QQptZMotorcyclesQ5fPartsQ5fAccessories

Thor's Hammer! · « **Reply #1 on:** July 31, 2009, 08:10:56 PM »

Looking at more ebay auctions, I am thinking these carbs came off a Nighthawk 750.

There are two fuel nipples that were not connect to anything between 1 & 2 and 3 & 4....perhaps this was why the bike wouldn't run?

Off to search to nighthawk carb rebuild info.

Will these carbs even work right on my CB750F??

razor02097 · « **Reply #2 on:** July 31, 2009, 08:12:59 PM »

Quote from: mismith356 on July 31, 2009, 08:10:56 PM

Looking at more ebay auctions, I am thinking these carbs came off a Nighthawk 750.

There are two fuel nipples that were not connect to anything between 1 & 2 and 3 & 4....perhaps this was why the bike wouldn't run?

Off to search to nighthawk carb rebuild info.

Will these carbs even work right on my CB750F??

Actually they are probably vents...

honda750k · « **Reply #3 on:** July 31, 2009, 08:22:09 PM »

Yup, those bear STRIKING resemblance to Keihin CV/CVK carbs, which have a vent tube between 1-2 and 3-4 as well. you dont plug those, just leave them open.

Thor's Hammer! · « **Reply #4 on:** July 31, 2009, 08:34:56 PM »

Quote from: honda750k on July 31, 2009, 08:22:09 PM

Yup, those bear STRIKING resemblance to Keihin CV/CVK carbs, which have a vent tube between 1-2 and 3-4 as well. you dont plug those, just leave them open.

Thanks Fellas! Good to know.

What do you all think...will these carbs be ok on the SOHC 750 motor?

bucky katt · « **Reply #5 on:** July 31, 2009, 08:40:40 PM »

i woudlnt use them i'd go with a set of the carbs that came on that bike. the cv carbs can be difficult to tune i understand

Thor's Hammer! · « **Reply #6 on:** July 31, 2009, 08:41:55 PM »

OK...just found a site where they talk about doing a jet kit on a 1993 750 Nighthawk.

I am 98% sure these are the carbs I have. In one pics, you can even read KEIHIN VE.

So...the big question now is...will these carbs works as they should on my older 750F SOHC engine or will they flow too much fuel and or air?

Here is the site I found:

http://www.nighthawk750.com/mods/dynojet.html

honda750k · « **Reply #7 on:** July 31, 2009, 09:55:55 PM »

Quote from: bucky katt on July 31, 2009, 08:40:40 PM

i woudlnt use them i'd go with a set of the carbs that came on that bike. the cv carbs can be difficult to tune i understand

actually quite the contrary. tuning CV carbs is very easy if you've got the right jets for your needs.

MRieck · « **Reply #8 on:** July 31, 2009, 10:43:08 PM »

Quote from: honda750k on July 31, 2009, 09:55:55 PM

Quote from: bucky katt on July 31, 2009, 08:40:40 PM
i woudlnt use them i'd go with a set of the carbs that came on that bike. the cv carbs can be difficult to tune i understand

actually quite the contrary. tuning CV carbs is very easy if you've got the right jets for your needs.

I totally agree

honda750k · « **Reply #9 on:** July 31, 2009, 11:43:44 PM »

For me, it may just be me, but those CVs are the easiest things ever to actualy dial in. just get the right jets for your application, set your pilot screw to 2.5 turns out, synch em on the bike. DONE.

if you want HARD, a freakin poulan chainsaw has a HARD to tune carb. although I may just be well above average when it comes to bike carbs.

bucky katt · « **Reply #10 on:** August 01, 2009, 12:49:19 AM »

i stand corrected gentlemen, i had always heard that the cv carbs were a nightmare to deal with.

honda750k · « **Reply #11 on:** August 01, 2009, 01:17:12 AM »

nope, that honor goes to Amal carbs. or newer mikunis. words cannot express how much I HATE mikuni's carbs unless I get into profanities.

Thor's Hammer! · « **Reply #12 on:** August 01, 2009, 03:38:42 AM »

I'll let you know if I can make these things work or not later on.

It sounds hopeful though.

Gonna clean em up (the are hella dirty) and try to get the bike running today.

Bill/BentON Racing · « **Reply #13 on:** August 01, 2009, 06:16:50 AM »

I vote for Amals or those flatslides Drouin had on those old supercharger kits,but on your 750F,it had 26mm carbs? you can put on 70-76 linkage carbs off any K model along with the manifolds and notice the improvement,lots of these out there,28mmfor these carbs.Bill

Thor's Hammer! · « **Reply #14 on:** August 01, 2009, 12:26:31 PM »

Well...whatever the heck the carbs are off of, they work on the my CB750

They need to be rebuilt with new needles and plunger diaphragms (if that's what they're called)...but they do run the bike with free flow fuel...if the pit cock needs vacuum...no love.

Still interested if anyone knows exactly what these carbs are off of or how I would identify what year they are so I can look into a proper rebuild kit.

Bill/BentON Racing · « **Reply #15 on:** August 01, 2009, 03:56:37 PM »

Honda CB650SC 1983 & 84& 85 used VE54A,float level 18.5mm,main jet 115,slow jet 35,pilot screw 2&5/8ths out,these stock jets are a little small for 750's,but see what he had in them,proably have to richen it up.Good Luck,Bill

Thor's Hammer! · « **Reply #16 on:** August 01, 2009, 06:56:28 PM »

Thanks Bill!!!

Much appreciated!

Bill/BentON Racing · « **Reply #17 on:** August 01, 2009, 06:59:27 PM »

You are very welcome,Let us know how they work and what jets are in them,Thanks,Bill

countrygreg · « **Reply #18 on:** August 01, 2009, 09:30:04 PM »

No, but you can rule out 1979 - 1982 Cb750 DOHC carbs. Try searching the Sudco web site.

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Author Topic: Can you name these mystery carbs?? (Read 6068 times)

countrygreg