I've seen / heard of these adjustable main jets available for S&S carbs, and wanted to know how they hold up, how they work, pro's / con's, etc.

Seems kind of thrifty to be able to adjust a jet on the fly, but what's the reality? I am considering re-jetting anyway, so is this a viable option, rather than buying a whole bunch and tinkering until I get it right?

And, of course, does anything like this exist for the intermediate as well? That's probably asking too much, I know - but it never hurts to ask!

Thoughts appreciated.


- Al

 

I have no experience with the S&S.

With the Keihin you have to drill a hole in the float bowl and insert a mechanism that attaches to the main jet. You have to drill the hole very accurately. The kit comes with a tool to mark the spot but it is quite crude. The kit includes an oversize main jet and an adjustment mechanism. Then you have to readjust it every time you remove the bowl for service.

I have one on my shelf that i will never install.

 

It's quite simple actually and very easy to do. Simple cut off the fuel, pull the bowl and you can change the main and intermediate in a matter of 5 minutes. The down side to this is a lot of people start changing their jets at the first sign of trouble which usually just masks another problem only allowing it to get worse for the temporary relief they get from re-jetting. I love my S&S carb, hence the reason I don't want to go back to the original if I don't have to.

 

I run a Bendix with adjustable jets and it is very thrifty to be able to adjust on the fly.The down side is that I find my self messing with it all of the time. If I am out at night and its cool I will richin just a touch to get what feels like the best mix. I have heard good and bad about the Bendix but its simple and was easy for me to set up. I was able to get it close in the garage then take it out for a ride adjusting along the way to dial it in.

T-Ron

 

This much I have gathered about the S&S adjustable so far: no drilling necessary (I'm assuming this is because the main jet is directly in line, conveniently, with the bowl plug), and I guess you just have to switch out the existing main jet with an oversized one. Then a sort of "plug", being the adjuster, can be screwed in/out to control the flow of fuel through the jet.

So, this thing actually works? I'm what you might call "cheap" and "lazy", but I don't like to skimp on my bike unnecessarily. So this seems like a good solution because I won't have to take the carb apart more than once to install it, and I won't have to purchase multiple jet sizes, only one of which I would ultimately use.

I saw your ancient flame thread on that adjustable jet when I searched the forum, Mick. You never wound up installing it eh? I don't blame you - I wouldn't want to drill a hole in my rather expensive carb, either.

Readjusting after servicing could be a pain, I suppose - but I'm more concerned with functionality (do they loosen from vibration and fall out of adjustment? I'm assuming these actually DO work), ease of use, and whether this thing looks, to be frank, really awful hanging off the bottom of my S&S.

Also, anyone running an S&S, do you tweak the carb float to the default 1/16" - 1/8" from the rim, or do you go leaner? Mine's shy of that marker right now, and still seems too rich.

Cheers all.


- Al

 

Never had mine loosen on me so I cannot say that is a concern, just a tad past "emph" and I've never had problems. As far as falling out of adjustment I'm not really sure how that would be possible, I would think you have quite the opposite situation. I can remove the entire piece and service it any time I feel, which IMHO would ensure it stays in adjustment longer unless you break your carb down on a regular basis and clean the entire thing.

Ease of use wise it's pretty retard proof honestly. Pull the bowl and you have access to both your main and intermediate jet, change one, both, none, simple cleaning...etc. There really aren't any additional parts hanging out of the bottom of your carb since everything is located inside the bowl, not sure what you were referring to there?

I run my float in the recommended 1/16th - 1/8th, no reason not to, like said if I have a major problem where I feel being richer or leaner would make a difference I can adjust a jet.

Purchase wise I would recommended getting the jets you plan on using, then 2 sizes in either direction.