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Post subject: CB350 Carb Rebuild Posted: Fri Mar 15, 2013 8:08 pm

Post subject: Re: CB350 Carb Rebuild Posted: Fri Mar 15, 2013 8:13 pm

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CB350 Carb Rebuild

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

Hi All,

Currently rebuilding the carbs on my '71 CB350 K3. Everything is cleaned up and ready for

assembly, and I'm wondering if I need to be putting gasket sealant on the float bowl gasket,

or if I can get away without it.

I also have some questions about the rebuild kit. I purchased kit 16010-344-305. It came

with a small metal washer, and I can't figure out where it should go. I definitely didn't take

one off during disassembly. I'm using the Clymer's manual, so maybe it doesn't go that far

into the carb. Secondly, is there suppose to be a gasket on the idle mixture screw? Once of

my carbs had one, the other didn't, and I've found assembly drawings showing both. It looks

like the kit includes one for it.

I'll writeup the rebuild process here once I finish this up.

_________________

1972 Honda CB350 K3

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J-T

Moderator/Supporting Member

Sounds like all the stuff that goes with the idle mixture screw.

First you put the spring on the screw.

Post subject: Re: CB350 Carb Rebuild Posted: Fri Mar 15, 2013 8:23 pm

Joined: Sun Jun 21, 2009 4:22 pmPosts: 3549Location: Lennox, South Dakota Motorcycle(s): 1981 CM400T, 1982GL500

Then you put the small metal washer on the screw.

Then you put the rubber o-ring on the screw.

Pictures would help.

_________________

JT

81 CM400T Under re-construction

82 GL500

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

That's kind of what I was thinking, though the washer has too large OD so it must go

somewhere else. Is it ok to put the spring on the screw, then the rubber o-ring without a

washer?

Attachments:

DSCN4557.JPG [ 192.4 KiB | Viewed 544 times ]

_________________

1972 Honda CB350 K3

Post subject: Re: CB350 Carb Rebuild Posted: Fri Mar 15, 2013 10:20 pm

Post subject: Re: CB350 Carb Rebuild Posted: Fri Mar 15, 2013 10:37 pm

Post subject: Re: CB350 Carb Rebuild Posted: Sat Mar 16, 2013 6:44 pm

1972 Honda CB350 K3

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Mydlyfkryzis

Moderator/SupportingMember

Joined: Wed Jul 04, 201211:00 pmPosts: 2458Location: Northern NJ USA Motorcycle(s): 1976CB360t, 1991 Nighthawk750

That washer looks like the gasket for the bowl drain screw on my CB360. Do your carbs have a bowl

drain?

_________________

Richard

Mydlyfkryzis = Mid Life Crisis

My Build: http://www.hondatwins.net/forum/viewtopic.php?f=5&t=16466

______________________

1991 Honda Nighthawk 750 "Big Red"

1976 CB360t "Sophie"

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

Yes, I have a bowl drain, but they have a rubber o-ring gasket. The washer is the same size

though, does the drain require both a gasket and washer?

_________________

1972 Honda CB350 K3

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asdfqwer426

Twins Addict

Joined: Sun Aug 29, 2010 12:38 pmPosts: 536Location: Winona, MN

its not uncommon for the guys that make carb kits to try to make kits that fit multiple years

of a single model, or sometimes even different models. I would just look at the carb parts

diagram online, make sure everything is there, and call it good.

I could be mistaken, but i'm trying to remember my 350 carbs and i dont remember there

being a washer like that anywhere. the float bowl is just an o ring.

the reason you want a washer on the idle screw is because the end of the spring can tear up

the rubber o ring. the washer is just a flat spot for it to sit on. i'm sure it would be fine

without one for a bit, but it will likely rip it up eventually. i would recommend using a washer.

finally, you mentioned that one of the idle screws had a gasket (i assume you mean o-ring)

and one did not, its likely still stuck in the hole it sits in, as many of them often are. you'll

have to get it out or at least make sure its not in there before you put it back together.

finally, its also likely that your small washer could be in there stuck with the o ring too.

good luck, hope it all works out.

Post subject: Re: CB350 Carb Rebuild Posted: Sat Mar 16, 2013 10:36 pm

Post subject: Re: CB350 Carb Rebuild Posted: Sun May 12, 2013 10:05 am

good luck, hope it all works out.

_________________

Nick

CL350 K4 (pamco installed)

CB500T cafe (pamco, single unit kohler reg/rect)

81 yz125

80 xr200

83 xr350r

1980 CX500C (3 of them. one runs, working on number 2)

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

I decided the same and didn't bother with the aforementioned washer. For the idle screw,

there was nothing stuck in the carb. Neither had a washer, and only one had an o-ring. I

decided to throw it together and get it on the bike anyways. Everything seems to be running

well, but maybe I'll try to get a small washer down the road. I also decided not to put any

sealant on the float bowl gasket.

Here's a web page with some good pictures of the process. I'll try to get some of mine on

here later. http://cb350.blogspot.com/2007/05/carb-rebuild.html

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1972 Honda CB350 K3

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

Alright, so I finally have some time to sit down and write about the carb rebuild and post

some pictures. I'll write it as a series of posts so I can keep the associated pics with it. It

was done for a CB350 K3 following the Clymers manual. First step, pull the carbs off the bike.

Second step disassemble and clean. Start by removing the top cover (with the 4 screws), the

diaphragm return spring, and the diaphragm/slide assembly.

Attachments:

File comment: Dirty carb.

Post subject: Re: CB350 Carb Rebuild Posted: Sun May 12, 2013 10:12 am

DSCN4534.JPG [ 91.64 KiB | Viewed 439 times ]

File comment: Remove cover.

DSCN4536.JPG [ 92.08 KiB | Viewed 439 times ]

File comment: Pull the diaphragm / slide assembly.

DSCN4537.JPG [ 97.51 KiB | Viewed 439 times ]

_________________

1972 Honda CB350 K3

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jp_boardrides

90cc

Now remove the float bowl (this also has 4 screws), the 2nd main jet, needle jet, primary

main jet, and main jet holder. Being my first time, I had a hard time figuring out which

needles were which so I pulled everything I could find. I don't think it matters much, just

make sure they go back in the same place when you're done (taking pictures helps). Then you

can remove the float assembly pivot pin and the float assembly.

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

Attachments:

File comment: Dirty float bowl.

DSCN4538.JPG [ 97.22 KiB | Viewed 439 times ]

File comment: Inside float bowl.

DSCN4539.JPG [ 98.8 KiB | Viewed 439 times ]

File comment: Jets

Post subject: Re: CB350 Carb Rebuild Posted: Sun May 12, 2013 10:21 am

DSCN4541.JPG [ 97.24 KiB | Viewed 439 times ]

File comment: Float assembly removed (assembly and pivot pin in lower left of pic).

DSCN4543.JPG [ 101.98 KiB | Viewed 439 times ]

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1972 Honda CB350 K3

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jp_boardrides

90cc

Joined: Wed Dec 01, 2010 7:29 pmPosts: 49Location: Pittsburgh, PA Motorcycle(s): 1972 CB350 K3

Now remove the float needle (it is by the black retaining clip in DSCN4543.JPG) and the float

valve seat retainer clip. You should be able to pull out the float needle valve seat now.

Clymers recommends using a pair of needle nose pliers with the tips wrapped in electrical

tape so you don't damage the part. Seems to work well. The next step, which I found tricky,

was removing the pilot jet and slow speed jet. These are the two long ones shown in the

attached pic. You must use something soft to press these out, such as a plastic or fiber rod,

so you don't damage them. I had neither of these things, but I managed to carve down a

plastic air pump nozzle and get them pushed out.

Attachments:

File comment: Pilot and slow speed jets.

Board index » 250's, 350's and 360's (CB,CL,CJ,SL) - 1968-1976 » Fuel Supply and Carburation All times are UTC - 5 hours

DSCN4544.JPG [ 112.49 KiB | Viewed 438 times ]

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1972 Honda CB350 K3

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