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Author Topic: F2 Carb Cleaning  (Read 6393 times)

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Offline Terry in Australia

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F2 Carb Cleaning
« on: March 26, 2005, 02:58:42 AM »
Okay, let it be known by all men that I, Terry, F2 builder extraordinaire and unemployed porn star, have posted the first technical question in the new SOHC4 site!

OK, so I'm pulling my 1977 F2 carbs apart tomorrow, apparently my #4 cylinder pilot jet is blocked, as the bike won't idle on all four cylinders, but as soon as I give it some gas, it runs fine on #4. When I bought the bike in a hellish state it was the same, but I put this down to the zero compression in that cylinder due to a PO leaving out one of the piston circlips in that cylinder, allowing the wrist pin to wander up and down the cylinder, wearing a .5mm channel.  I've replaced the cylinders as part of the resto, but still haven't gotten it to idle on #4 yet? ???

Anyway, there's been a lot of sitting since the rebuild a year ago, and the bike has barely turned a wheel in that time. I originally cleaned the carbs out with some disassembly, but I couldn't remove the pilot jets, (pressed in) Does anyone know how/if i can safely remove them and reinstall them after I've done some serious cleaning? Any other pointers of note from the collective genius that this site comprises? Thanks Guys, in advance! Cheers, Terry. :-*
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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Chris in Ramsey

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Re: F2 Carb Cleaning
« Reply #1 on: March 26, 2005, 05:05:40 AM »
Terry, I sure hope that the pilot jets can  be removed and re-installed, as that's what I've done on my F2 carbs! Grip the jets near the base with a pliers(NO SLIPPING ALLOWED) and twist as you pull straight out. You've probably received similar instructions from the directors of porn movies you starred in.
  After cleaning, the jets can be tapped back in, being sure that they seat all the way(the jets are slightly shouldered) This does work OK, it's also the standerd procedure on late-model 550 carbs. Good luck! 
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Offline BobbyR

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Re: F2 Carb Cleaning
« Reply #2 on: March 26, 2005, 08:30:25 AM »
I have had luck with old Guitar strings, spray cleaner and high prerssure air cleaning them out. While I have heard others pull them out I don;t have the stones to do it. If the clog is from Vegemite you may all well give up and sell the Bike ;D.
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Offline jtb

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Re: F2 Carb Cleaning
« Reply #3 on: March 26, 2005, 05:15:27 PM »
Terry, the pilot jets on my F2 carbs have been pulled out and replaced by the PO.  He also put in 115 mains.  After I put in 105's when I rebuilt the carbs, the bike wouldn't run for sh*t.  I Put the 115's back & it runs much better.  I did get some old guitar strings from my neighbor next door (he used to play background music for porn movies, perhaps you've met) and used them to clean out the pilots. 

The owner of the MOST beautiful 1977 CB750F2,
John
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1977 CB750F
1985 V65 Sabre
1986 VFR 750 (gone but missed greatly)

Offline Terry in Australia

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Re: F2 Carb Cleaning
« Reply #4 on: March 26, 2005, 09:27:59 PM »
G'Day John, how are you mate? Yeah, I probably know your neighbour, and maybe his wife and her sister too! (Black Betty?) Ha ha, now as to who's F2 is the prettiest, well, yours can be the most beautiful in Birmingham, and mine is definately the sharpest in Mill Park, he he! Have a good one mate, I'll try those bigger jets while I've got the carbs apart, I've almost finished painting Tim's car, so I'll be able to play with the bike again tomorrow! Cheers, Terry.
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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline MRieck

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Re: F2 Carb Cleaning
« Reply #5 on: March 27, 2005, 08:38:19 AM »
Get rid of those carbs and get some CR-29's. You're going to need them when I get done with your head! ;D
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Offline Terry in Australia

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Re: F2 Carb Cleaning
« Reply #6 on: March 27, 2005, 03:03:34 PM »
G'Day Mike, I've got a set of early Mikuni flat slide "smooth bore" race carbs off an old Suzuki GSXR race bike, they are super lightweight compared to the OEM boat anchors, and I reckon they can be made to fit the CB750 head, would they be ok? Cheers, Terry.
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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline kaceyf2

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Re: F2 Carb Cleaning
« Reply #7 on: March 28, 2005, 06:00:12 AM »
 ::)   Terry, High Bro, and well done for being the first poser, sorry, I meant poster! (ha ha)
 If you send me your carb body, i will run it through my ultrasonic cleaner,that I have for my tatoo gear.
No "poking" no "scratching" no risk of widening orifices or any other damage , and its totally thorough.  Nothing can withstand the effects of ultrasonic cleaning, it was deseigned for removing caked on crud from inaccessable places, on a microscopic level.
The first time I used it was on my own F2's accelerator pump body, The bit were the "square" brass plug is factory fitted into a round hole.  You cannot clear this out with a "bit of wire" nor can you remove the plug or get into it in any way, once totally blocked, its a major headache......
I dunked it into the ultrasonic, switched it on , and in seconds, the crud was rising in a string of exploding bubbles....job done!  Nuf said.
many regards.
kaceyf2
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In my own experience...
It wasn't a Previous Owner who didnt know what he was doing that messed up your bike, it was The Previous owners mate who THOUGHT that HE did.

low-side

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Re: F2 Carb Cleaning
« Reply #8 on: March 28, 2005, 10:14:51 AM »
Hey Terry, I just cleaned the world's nastiest set of F2 carbs, every idle jet was clogged solid and the bowls were growing that green fuzz inside.  I filled the jets with Berrymans carb cleaner and left it overnight and just shot air through them and now they're clear.  The only problem I'm having is that I can't find my repair manual and can't remember the float height.  Do you know off-hand?
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Offline jtb

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Re: F2 Carb Cleaning
« Reply #9 on: March 28, 2005, 11:53:27 AM »
Hey, Low-side.  14.5 mm +-0.5 mm.  (.571 " +- .02")

The owner of the MOST beautiful F2
John Baldridge in Birmingham, AL
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1977 CB750F
1985 V65 Sabre
1986 VFR 750 (gone but missed greatly)

Offline CB750R

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Re: F2 Carb Cleaning
« Reply #10 on: April 05, 2005, 11:22:25 PM »
I just found out, I have a 77 K engine in my F2 frame!!! how do I know if I have F2 carbs or not?? I'm a new owner, and I've ordered a kester carb kit for 77CB750F now I'm worried I bought a lot of useless stuff, whats the proper part number for the 77 F2 carbs???

Thanks
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