pod air filter info

[bpeck54]

Hello again and thanks for the latest answers to my questions and here is the latest one.

I have a 1980 sf with a four into one header, the carbs are the ones with the
rubber air needle jet block out next to the main jet. I use a clymer manual that states the main jet sizes are 115 and 120 Iam swiching to pod filters and will
they affect the main jet sizes.

[DGXSER]

Well, you have two issues here. First off, if you have the "bastard" 80 year carbs with the crossover tunnel and the rubber caps on the pilot jets, in my opinion, you should have the 137.5 main jets. The manual is based on the fully changed over carbs that do NOT have the crossover tunnel and the plug in the pilot jets.

As to adding pods to the mix, yes, with a 4-1 and pods, most find they need to increase the mains a little to compensate. How much, well there is a jetting guide on the site, I forget where though, tech tips or the FAQ section. That will give you some idea where to start, but where you end up is typically a game of trial and change.

[bpeck54]

Thanks dgxer , in your opinion whick carbs work the best.
But i will try and live with what I have for now.

Bill Peck

[DGXSER]

Honestly, this is my first round with the earlier model carbs. I think they each have their benefits and drawbacks.

The early model ones have the external vents to deal with, not that it is horrible or problematic really. You also have the metal to metal float needle valve issue which does not seal very well (thus the reason for the XV920 "upgrade"). But you also have the mixture screw exposed so it does not tend to get stuck and impossible to remove like the ones in the newer model carbs that are stuck down inside that tunnel. But then, the mix screws on the early ones have a tendency to snap off in the hole in the carb throat.

The newer carbs also idle screw seems like an easier location to get to when the carbs are mounted and on the bike with the tank on. The viton float needle valves, also the plastic floats that are not as easy to leak or dent.

In the end, I think it is six of one half dozen of another, and either set should tune just as easy and well for any year engine. Just my opinions though.

[bikerphil]

the "bastard" 80 year carbs with the crossover tunnel and the rubber caps on the pilot jets, in my opinion, you should have the 137.5 main jets

Don, I've worked on many sets of the 80 carbs with the rubber plugs, and I've never had to go with a main jet larger than 120.

[DGXSER]

Ok Phil, thanks! Only seen and worked on one set, and we never got them tuned in right. We had 120 mains and low end and mid range was always crap IIRC. My thought was the main was not big enough to draw the pilot and main needs and needed to go bigger, just like in the 78-79 carbs. Guess I was incorrect, dang...twice in one year!!! I am going down hill!!

[TomRodgers]

I would tend to agree with Phil!!! I have 125 mains on Sunshine, and runs well, maybe a bit rich at times, but never fouling...this winter i may install some 120's to test color and mpg....however....the mpg is usually controlled by the left side of my brain rather than anything mechanical on the bike