1979 Carb Rebuild (Pt 1)

Caps for the 6 pilot screws are not required. 3 to 3.5 turns is the generally accepted starting point for the pilot screws. A "Color-Tune" can dial them in but I've found that the "Blue" range is relatively broad, so some time is required to find a middle point.

Any idea why the carb plungers are different on the carb rebuild kit I've bought? The new ones don't have the small needle piece on the bottom. This is a shame as one of mine is slightly bent.

Are these off a different or later model, and are they interchangeable?

I too have found like Scotch the Blue Range to be quite wide on the mixture settings when setting with a Colortune Plug, so I take it slowly to the Rich end of the scale (Yellow Burn) and set them around 1/2 a turn IN from there as its better and safer to be slightly Richer (cooler) than Leaner (hotter).
This setting gives me ideally coloured plugs and instant starting on the button with very litte choke even when cold.

Pete F
Uk

Are these off a different or later model, and are they interchangeable?



Good question ! I have no specific answer, regarding originality or OEM style change. I once thought of the "extension" as a metering needle. I've discounted that premise, primarily because it's not tapered so can't progressively meter. The "extension" or "pin" being referred to seemingly serves no true purpose, as I can determine because it's out of the small port, in the full choke position. Hence, it's been eliminated in aftermarket plungers. I would recomend using the same style of plunger despite them being interchangeable.

and because I'm still working on Java #2

Without getting into symantics, the bare bones of this topic are: For the choke plunger to begin to deliver choke-fuel, it must be high enough to expose the two ports in the plunger bore. In the FULL lift postion the bottom of the plunger (forget the "extension") simoutaniously fully exposes both the fuel port (to the intake manifold) and the supplementle air port ( opposite side of plunger bore, under the diaphragm). This is the position that will deliver maximum fuel for the choke circuit. The amount of fuel being delivered will depend on the amount of port esposure but I believe this becomes an academic point once the lifted plunger exposes approx. 1/3 or more of the ports.
Although straightening the bent extension could be accomplished, care must be used. If it's not perfectly straight, binding will definitely occur and the internal spring which closes the plunger may not be strong enough to seat the plunger, correctly. This may seem counter-intuitive given my previous comment about fuel only being delivered to the choke circuit when the plunger is fully lifted but the concern would be "leakage" of fuel past the plunger and plunger seat if the two are not in full contact when the choke is OFF. How much, if any leakage would be present will be determined by the overall condition of the plunger bore, bore-seat and seal surface, AND the external stem seal. While on the topic of the external stem seal: At the age they are they are pretty much hardened and are more of a dust seal, now. They can be removed and reinstalled easily by warming them with a hair dryer. I am not aware of replacent being available.
Now is good time to consider:
www.kz1300.com/index.php/forum/carburato...ir-mod?start=6#23179
The various methods are merely workable options. Regardless of the option used - It works, and the ease of cold starting is significant !
Perfect timing ! On to Java #3.....and have a nice day!

Wow, thanks Scotch... fair to much information, I'll have to read it several times.

1 of my chokes is slightly bent on the shaft, so when I tighten the nut, the plunger locks and doesnt return. I've had to leave it an 1/8 turn out and put some red loctite on the threads to seal it. Not ideal.

Maybe the plungers stops it enriching but allows you to raise the tickover at low choke openings.?

Wow, thanks Scotch... fair to much information,
You asked me "what time is it?" and I thought I'd explain how the watch was made, first. It was raining (still is) and I was bored.:S
No, your "Fix" is not ideal.
That's as short an answer as I can come up with !
It's 4:50pm......and I'm outta here !