Re: 80 Moby Carb questions

Pat Finley /

Ron,

I'm not really sure. (I have now attached the pictures of the disassembled carb for you to review.)

In answering your question, I can only say that based upon the picture of the carb I posted (pre disassembly), I would have said the choke cable enters the carb from the bottom of the hollow choke assembly. However, this contradicts your thoughts as well as the Motobecane manual. It doesn't seem logical either because it seems like it would be harder to create tension. However, I swear this is how it was on my ped for a long time. You can see the end of the choke cable right there in the picture on the top of the carb...

I'm lost.

Re: 80 Moby Carb questions

Ron Brown /

Pat,

I am now on information overload! Great pictures!

I just gave myself a huge "dope slap" when it dawned on me that when you refered to the cable being installed from the bottom, you meant the bottom of the choke internals. All this time I was under the impression that the cable entered the carb from the bottom instead of the top.

I had never considered this as I have not disassembled my choke mechanism from the cable. It is now obvious to me that cable installation involves threading all the components onto the cable then threading the cable back into the outer case. The control end is then clamped by a screw clamp.

Time out to consult manual....

My manual shows what looks like your plastic piece going into the carb first (the brass piece may be inside this), then the spring. In the cable replacement section, it talks about replacing the cable as I described above.

In the manner of all good shop manuals, it is just short of explaining it in enough detail to be able to resurect a handfull of parts. You have to have a complete carb to look at.

It appears that no one with a carb in hand is going to respond here and that you will continue to inundate us with jpegs until this puzzle is solved. : )

Sighs and heads for garage to pull carb of ped....

Will post results.

Ron

Re: 80 Moby Carb questions

Ron,my face is RAW with all the dope-slapping I've had to do lately.I think yours will do for me this time.So he's talkin' about the cable hooking into it at the bottom of the whole mechanism that removes out the top.Well,maybe I can stand one more....KEEEETTTCHH!! That's better! Where's the Oil Of Olay,Linda!

Re: 80 Moby Carb questions

Ron Brown /

....returns from garage administering "dope slaps" with both hands alternately...

OK, forget what I said many posts ago about brass slugs with rubber tips blocking gas passages. This is true of every Jap bike I ever disassembled but I obviously underestimated the deviousness of the French!

Here is how the "choke" works. The hole into which the brass slug fits is drilled all the way through the carb body (if anyone is aware of any plug or cap for the bottom end of this hole I would like to hear about it). The diameter of the hole is stepped to a slightly smaller diameter about half way down. The brass slug is also stepped in diameter so that if you drop it in the choke opening, the step on the brass slug sets on the step in the bore. The slug is a sliding fit in the choke bore for both diameters. A hole is drilled from the engine side of the carb venturi, through the choke bore and into the float bowl. This hole passes through the choke bore larger diameter just above the step to the smaller diameter. With the slug in its lowest position, the large diameter of the slug covers these small holes on either side of choke bore. This is the choke off position. When the slug is raised by the cable, the larger diameter of the slug is raised above the through hole which is now in line with the smaller diameter of the brass slug. This creates a cavity between the small diameter of the choke bore and the large diameter of the brass slug. Vacuum in the intake causes fuel to be sucked through this cavity, around the brass slug and into the intake.

Is this prone to leakage of gas and sucking in dirt? Sure, but it is French!

Ok, now to putting yours back together.

I am fairly sure that the nylon piece you have is the piece the outer case of the cable fits into on top of the carb. Before you start you may want to verify that the cable case fits into one end of this plastic piece. Mine is different, the placement of my carb requires this piece to have a severe bend as it leaves the carb.

Using a 10 speed gear shift cable inner, thread onto the end without a nipple, the brass slug, small diameter first. Then the spring, followed by the brass washer(I think dimple down but see how it mates with the nylon cable guide and carb top). Lastly, the nylon sleeve, with the cable sheath end on last.

Assemble the choke mechanism to the carb top with the carb top between the spring and the brass washer. Install the carb top. Slip the outer cable over the inner and check for length to the choke control. If required, slide the outer back off and cut to length. Shorten the cable adjuster on the control, fit the inner cable in the cable clamp in the choke control leaving about 1/16" of play in the cable with the control in the off position.

Hope this works for you,

Ron

Re: 80 Moby Carb questions

See what several strategically placed dop slaps can do,Pat? Masterful,Ron,masterful job!

Re: 80 Moby Carb questions

See what several strategically placed dop slaps can do,Pat? Masterful,Ron,masterful job!

Re: 80 Moby Carb questions

Pat Finley /

Ron,

Thank you so much. I really appreciate all your effort on this! Thanks for the detailed description of how it works too.

Pat Finley

I'll let you know when I'm cruising and snap a photo. What's another 500 KB file to wait 10 minutes to view?

Re: 80 Moby Carb questions

Ron Brown /

Pat,

Thanks, I can cancel that new, larger hard drive now. : )

Ron

Re: 80 Moby Carb questions

Way to go,Pat! Swarm and Destroy!!

Re: 80 Moby Carb questions

Pat Finley /

Don,

Going out now to put it together. Got new cables. We'll see what happens...

Pat

Re: 80 Moby Carb questions

Okay,Pat!All the best! And how `bout that guy Ron Brown stickin' with you all the way?Way to go,Ron!

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