Topic: 350f Carb Questions

[mlinder]

Hello folks. Got the 100 dollar cb350 running today. Pulls to 10k nicely.

Got 2 carb issues though:

Issue 1: The choke lever springs seem backwards to me.
The springs want to pull the the armature to close the butterfly valves at the intake side of the carbs, closing the choke. I've got a piece of wire holding it open right now. It seems to me the spring should want to pull the choke open not closed.
Does this sound right?

Issue 2: It idles at 3k right now. With the air filter off, it idles at 2k.
The idle screw is backed all the way out, with the armature the scrwe pushes not even touching it at this point.
I've tested for airleaks, none appeared. I HAVE NOT checked the mixture screw, so I guess I'll go do that and get back on that one.
Anyway, hella fun bike. at about 6.5 k, that little bugger just starts to pull like a turbo was turned on or something.

Pertinent info:

Carbs pretty well cleaned.
Stock airbox, pretty clean filter.
New plugs
some aftermarket 4 into 2's, sound pretty loud, so may be less restrictive than stock.
72 350f

[mlinder]

Okey Dokey...

Mixture screws were out from between 2.5 and 3.5 turns.
Turned to 1 out, down to 1200 rpm idle. Seems ok.

Still can't get my head around the spring issue though.

[tomkimberly]

7/8 turns out from lightly seated +/- 1/8 turn.

Ru it with the air filter.

Hard to say about the choke issue with out any pictures.

Tom (on vacation somewhere in Colorado)

[mlinder]

Just took a little spin on the little fella around my little neighborhood.

My impressions so far:

where x = cb350f
and y = cb750k
and S = smile factor,

(S * x) = (S * (y * 2.5))

What a fantastic little bike.

I'll take some pictures of the choke linkage tomorrow. It boggles the mind.

I'm actually kind of jealous, this is not my bike, it's one I picked up for my girlfriend, which she paid for. She was tired or riding behind me on the cb750, so we got her this.

100 bucks.
about 14 hours of elbow grease and 35 bucks in #$%* to make it run.

Climbs to redline without a hitch.

Plugs are tan and beautiful.

Yeah, I AM jealous.

[CBGBs]

There may be an idle advance that is incorrectly installed making the choke plates out of spec and causing the idle to always be in advance. Just an idea.

[Trevor from Warragul]

The choke on the 350F closes the butterfly valves on the intake side (this blocks off the air supply & enrichens the mixture).  It also raises the throttle slides a tad (same as opening the throttle a little bit on start-up).  If you take the carbies off you'll see a nut & bolt that you adjust to control when the choke begins to lift the slides.  If this is adjusted incorrectly you can get a high idle even with the idle screw backed right off. 

[mlinder]

RIght, saw all that, had the carbs apart and cleaned them. I found the issue. Theres a weird little arm that controls the snap back that is out of whack, will deal with that tonight I think.