Gas Cap Revisited - A Solution!
Remember the handsome black-and-orange Chinese gas cap James Emad found on FleaBay? I was so taken with this piece that I ordered one before James discovered that it would not fit his bike, concluding that it was out of spec. I was disappointed at this news and just put the part on the shelf when it arrived. After another awkward, two-handed fill-up with the OE cap persistently trying to activate its "self-closing" feature and obstructing access to the filler aperture when held open, I decided to see what kind of modification to the tank shroud/tank opening might be needed in order to adapt the Chinese gas cap to my Duke. Like many of us here, I am frustrated with the OE cap: Mine sits relatively flush, but I have seen photos of several that were machined off-center and sit crooked; when opened, it maddeningly flops closed at every opportunity unless restrained by the non-pumping hand; it is a surprisingly heavy chunk of metal; It obstructs the pump nozzle and emissions cover when filling; some have reported that the key cover flap vibrates annoyingly; but mostly, it is just a totally unnecessary PITA to use. The simple act of putting fuel in the tank really does not need to be such a hassel.
So I took off my stock gas cap, unpacked the Chinese cap, and proceeded to test-fit the latter to the tank of my black Duke. I was prepared to use a Dremel and carbon fiber mat to reshape the tank shroud opening to make the Chinese cap fit. Strangely, however, I found that the bolt holes on the Chinese cap lined up perfectly with those on my tank. Hmm - the cap's filler hole and sealing gasket must now be out of line with the tank opening, I thought. But no, when I checked they were exactly in alignment. Furthermore, the Chinese cap appeared to be nicely centered over the tank shroud opening. Curious to see what would happen, I put in the three cap bolts and gingerly tightened them down. No drama - the Chinese cap simply simply snuggled up tight and flush to the tank shroud and sat there looking splendid. I took off the plug and verified that the cap and tank openings were in alignment, and the gasket was well-placed to seal the closure. "This looks too good to be true", I thought, "There must be a catch".
Still skeptical, I rode up to my usual gas station and parked the bike at the pump. The orange filler plug comes off easily and I set it on the seat. The pump nozzle goes into the filler hole without obstruction, one-handed. Iphone comes out to photograph this unaccustomed event. I uneventfully fill the tank and withdraw the nozzle. Not a drop spills. I replace the filler plug, hang up the nozzle and we are GTG. A NORMAL, hassel-free fillup. I ride home and check the tank for leaks - none, a tight seal. I subsequently went for a 60-mile ride, checking the new gas cap for leaks, possible vacuum lock or other misbehavior. None. It just does the job, unobtrusively. I am pleased.
So this, folks, is an easy solution to the annoying issues that have irritated many of us since acquiring a Duke. I'm not saying this is the only solution, but it is inexpensive, good looking and very convenient. I will look no further. Now that we have found the Spal fan and a viable gas cap alternative, two of the Duke's biggest shortcomings have been put to rest. On to the rear shock preload adjuster!
YMMV, but I find the stylish Chinese cap superior to the OE part in several ways: It weighs less than half of the OE cap; it looks great (I love the subtle touch of orange on the filler plug); it doesn't vibrate; it fits flush; it is relatively inexpensive; it requires no key; and most importantly, it eliminates all the refueling issues about which so many Duke owners have complained. It works for me. It looks good on my black Duke but would be even more striking on a white tank.
James Emad gets full credit for finding this very nice piece of gear. Looking at his photos, I can see the reason he thought the Chinese cap would not fit - his tank shroud is displaced somewhat towards the rear. James, no need to feel embarrassed - just take a Dremel or a file and adjust the screw/bolt holes on the front/ back and sides of your tank shroud until you can get it to sit perfectly concentric with the tank's filler hole. Then your Chinese cap will fit. Thanks for bringing this much-needed upgrade to the forum's attention.
Here is the link:
(Black CNC Fuel Gas Tank Keyless Cap Fit KTM 390 200 125 Duke O1 | eBay)
"If you don't know where you're going, you might wind up somewhere else."
2015 390 Duke
1980 Moto Guzzi V50 II (becoming a cafe racer)
1984 Moto Guzzi SP 1000
Last edited by Diploman; 04-17-2016 at 03:36 PM.