Ironhead Upgrade carb kit

[sungod]

Originally Posted by brucstoudt

sungod,it's not an H-D and i'm not sure of the size mm but i'm less than thrilled with it.

Got it.

[ericfreeman]

Best carb I've ever found for my Ironheads is a vintage Mikuni-Solex 36 PHH automotive carb adapted by Jerry Branch. First bought one directly from Jerry back in 1977 for my new XLCH that had a horrible flat spot in the stock Keihin. The new carb really woke up the engine and also gave fantastic fuel mileage due to it's efficiency. Although long gone now, I've managed to pick up a few and rebuild them. Very easy to tune with all jets accessible through a small cover on top of the carb. Only issue is they stick out a ways so if you have long legs this could be a problem. My 30" inseam is no problem. I'm running two of them on my '77 and '78 and wouldn't trade them for gold. Much better than the stock Keihin or the S&S Super E my '78 had when I bought it.

[kitabel]

That's a 2 bbl., similar to the Weber DCOE.
Is the manifold a plenum (merges both barrels before the manifold legs), or independent runner (each barrel feeds only 1 cylinder)?

[ericfreeman]

Yes, 2 barrel sidedraft carb similar to Weber DCOE only about 2/3 the size. Each barrel has a 36mm butterfly. You'd think it might be way to big considering the stock carb is a single 38mm throat. But it really works well. There's a common, highly polished plenum. Interestingly, adjusting the mixture screw on the front carb barrel actually affects the rear cylinder and vice versa for the rear screw. Appears the air flow acts like an X in the plenum for smoother flow.

[80HDXLS]

I am joining this discussion late. I had a Mikuni 38-9 with the KN air cleaner on my 1980 XLS. The Mikuni is easy to work with and did a very good job on my bike. I did replace it because I did not like how far the air cleaner stuck out, and I liked the look of the original air cleaner. I bought a couple of Keihin butterfly carburetors to cannibalize and the original type air cleaner. It was a process of trial and error to get the correct jet size, and its only been about 6 months, but the bike seems to run well and the gas mileage is about the same as I got with the Mikuni. Performance is good enough and I think it looks a lot better.