34mm Kadron Tuning

I've mounted these carbs on a new 1954cc motor. I've just finished the wiring on the car and have started it several times; no problems here. My question is, if I want to do some tuning on the carbs, is there a way to change the jetting, like has been discussed on the Webers, to richen, or most likely, lean out the mixture?? I haven't heard/seen any discussion threads, but they seem to be popular enough carbs.
-Time

Tim,

you'll find all the information you need on AJ Sims website

www.lowbugget.com/kadronpage.html

I run Kadrons myself and have found them trouble free so far.
Work great with a vacuum advance dissy too.

Simon

Thanks for the link; I checked out the site and it's very helpful. I just want to confirm some of the recommendations there with experienced Kadron users. My new VS came equipped with a 1776 cc engine with dual 40 mm Kadrons (I understand they use the stock cam). A friend who owns a VW shop adjusted them slightly since it was running a little rough and it's a lot better now. It starts right up in the morning and it's idling a lot better than it did.

With respect to the website, for a 1776 cc motor they recommend 135 mm main jets for the stock 28 mm venturies, 140 mm main jets for larger venturies, 52 to 57 mm idle jets and 170 aircorrection for larger venturies. It goes on to recommend 30 to 31 mm venturies also. It says that stock jetting for Kadrons is 127 main, 55 idle. Has anyone been able to use the stock setup right out of the box for engines like mine or do I need to follow the recommendations in the Lowbugget site? I don't want to start tinkering with things in a new car unless it's totally necessary.

Ricardo:

If it's idling smoothly, accelerates crisply and has enough performance to satisfy you in daily driving, then I would suggest that you not mess with them. Fooling with jetting, especially in addition to changing vanturi sizes and balancing between main and idle mixture jets, can quickly turn into a nightmare.

In my opinion, 140mm mains on 40mm carbs on a 1776 cc engine might be a little more than it wants to see and it may run pretty rich on that combo. Run with the stock combination for a while and see how you like it.

Gordon

Thanks for the peace of mind Gord! It's reassuring to get advice from experienced guys like you; especially since I don't want to start fooling around with things unnecessarily in a new car.

Even though the car is running better after being adjusted slightly (preliminarily, we might say), I'm convinced that it's still running rich albeit better than before. I guess we still need to tweak it a little bit until we get it just where we want it. I'm also convinced that the more you use a new car, the better it starts to work after a while; it seems as if the parts get used to working together and somehow fall into adjustment....weird but somehow true in my experience.

Keep in mind that most tuners jet these engines rich on purpose. A lean engine runs hotter head and cylinder temperatures, and since that is death to an air-cooled machine, most "out of the box" engines are pretty rich. If you go leaner, watch your temperatures.

Ricardo, Just remember that trying new jets is not a problem if you make only one change at a time, and evaluate it before you go any further. If it's not working any better then replace the original part and re evaluate before continuing to the next change. Keep track of all the changes on paper alone with a baseline of where you started from. Worst case senario you can go back to where you started, no harm no foul. And you may learn something. Eddie

Gee, that may explain why I seem to be accepted by the local Harley Biker crowd - we're all running a little rich (which also explains all that raw gas smell that follows us around!!)

Tim,

Remove the carbs and ship them to A.J. with all of your engine specs and as much info on your car and driving habits as you can.

We just had a set done up by him and the power/drivability/gas miliage/etc. was NIGHT and DAY! If was a totally new engine (1914cc) with the carbs set-up by him!

If you want to drive it for a while and have the carbs done up over the Winter, that's cool, but you shouldn't miss the opportunity to have them done up right. They'll be good forever and you won't believe the difference! I just can't say it enough, honestly . . .

TC

I called A.J. when I first bought my Speedster. He talked my ear off. The guy loves to talk about these carbs. He will answer any question at length. I bought the venturis, idle and main jets, and the air cleaner mounting kit. You tell him what you have for engine size and cam lift, he will send you what you need. This is the cheapest performance upgrade you can buy.

The carbs are very simple and easy to set up yourself with AJ's parts.

My original post was based on pure speculation. I've only 7 miles on the car, and am only adding ~1 gal. of gas at a time. Still working on the beast. My engine is a 'hybrid' size at 1954cc, but as far as carburation goes, it's been an absolutely trouble 7 miles !! One of my personnal aims is to have an economical ride; I've three other vehicles that average 20 mpg, so I'm thinkin' a 4cyl. ought to get better. It sure sucked that first gallon in a hurry though!! Therfore, I'm still thinkin'...
-Tim

Thanks for the tips guys; I decided to let it be (as the song says) for the moment. I went to inspect the spark plugs (only 200-something miles on them) and of course they were all black due to the rich mixture. I decided to clean them up with mineral spirits, check the gap and reinstall them. The first one I thook out was the one on cylinder one and as I cleaned it I noticed that the ceramic top part (is it called isolator?) was slightly cracked (not open but you could notice it and feel it with your fingernail). I bought a set of replacement Bosch plugs (the ones from factory are NGK)and will install them tomorrow. Do you think that could be the cause of a rougher running engine?