Kaweco Classic Sport Fountain Pen - Black

I really liked this pen for it's portability and size when capped. It's still large enough when posted to be used comfortably even if you have large hands. Mine was a bit hard starting even with a cleaning. It took 12 hours for the ink to fill the feed but after that it's been working fine. The one issue I have is how light weight the pen is. It doesn't feel great to write with because it's so light but it is a nice plus when it's in a shirt pocket.

Updates
Jon emailed me and helped me after I wrote this comment, which is super nice. I forgot to do the standard practice "flushing the pen out with a bit of dish soap". Well I forgot to do that last night, however, the ink was flowing smoothly this morning when I used it. Maybe the manufacturing oil is gone now. Anyway, it's a truly amazing pen now! I really enjoy writing with it.

Original Post
I love this fountain pen. It is crafted so elegantly. It's love at the first sight.

However, when I started to use it, I noticed that the ink doesn't flow very well. On the first day, it was really bad. I decided to give it two more days to see if the ink flows better. Now it's the third day. The ink does flow better, but the ink still pretty frequently, all of a sudden, flows poorly or not at all.

Could you help me to fix it? or just tell me why is it?

*I used Kaweco's ink cartridge.

With a 1.1 Italic, this has become one of my favorites. Inked with Noodlers Black, it leaves just the perfect amount of ink that gives you satisfaction you wouldn't expect from a pen in it's price range. The size at first almost turned me away, however I am glad I gave it a shot.

This is my first Kaweco and I love it. Tiny when capped. Disappears in a shirt or pants pocket (be careful lest it goes into the laundry!). The only reason I can see for getting it with the clip is to keep from having to fish for it.
Posted it fits my large hand nicely. I love the retro/industrial styling.
I have had the pen three weeks. Very smooth, with just enough tooth and excellent ink flow. I got it with the 1.5 mm nib that Wonder Pens swaps in. I have not seen anyone else offering this option. Saved me having to buy the nib I wanted separately. Way to go you thoughful people!
Truly an amazing pen: well made, highly portable, comfortable, dependable, cheap, and with a huge range of nib sizes.
Next on the agenda is to convert it into an eye dropper. Must also get an AL Sport.

I bought this pen in an extra fine nib, with the gold clip and short convertor, and have really enjoyed it. The portability is great and I don't find that the pen is difficulty to use when posted.

I did expect this nib to be a bit finer than it is in practice, but I have read that Euro/American pens in extra fine are slightly broader than Japanese extra fines.

Despite having a bit thicker line than expected; I really enjoy the looks of this pen; it's my only black business pen and it suits the purpose.