Gas Cap Revisited - A Solution! - KTM Duke 390 Forum
 59Likes
Reply
 
LinkBack Thread Tools
post #1 of 78 Old 07-06-2015, 09:30 AM Thread Starter
Senior Member
 
Join Date: Apr 2015
Location: Murrysville, PA, USA. A pleasant, wooded suburb of Pittsburgh.
Posts: 2,160
(Thread Starter)
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)

Cheers, Will

"If you don't know where you're going, you might wind up somewhere else."
--Yogi Berra

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.
Diploman is online now  
Sponsored Links
Advertisement
 
post #2 of 78 Old 07-06-2015, 10:08 AM
Senior Member
 
Hoover's Avatar
 
Join Date: Apr 2015
Location: Madison WI
Posts: 807
Nice job mate. Looks great.

2015 Speedy White one.
Mods: Bazzaz piggyback, MNNTHBX open airbox, K & N air filter, Werkes exhaust, R6 rear shock, PowerParts seats, G6 quick turn throttle, Spal fan, EI conversion, cheapo bar end mirrors and levers, Evotech tail tidy, Evotech spols and bobbins, R&G radiator guard, PowerParts chain guard, EBC HH pads.
Hoover is online now  
post #3 of 78 Old 07-06-2015, 11:39 AM
Member
 
pyxie's Avatar
 
Join Date: Jun 2015
Location: California
Posts: 52
Garage
Ooooooh love it! My gas cap sits a wee bit crooked and it annoys the heck out of me. This sounds like and looks like a great alternative. Thanks for the share!
pyxie is offline  
 
post #4 of 78 Old 07-06-2015, 05:56 PM
Senior Member
 
mejetski2000's Avatar
 
Join Date: Mar 2015
Posts: 1,497
Garage
That looks great, unfortunately I just bought the KTM stick-on faux carbon piece. So on some bikes if I understand you correctly Will, the shroud holes aren't always lining up with the holes in the tank itself ?

Pete

Pete in Maine
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
mejetski2000 is offline  
post #5 of 78 Old 07-06-2015, 06:46 PM
Member
 
Join Date: May 2015
Posts: 52
This is James... I'm still not understanding the solution to this.
I'm so stoked it worked for you, but I am also extremely confused as to how it now fits?
If you look at the pics I posted - the Chinese cap compared to the stock one (upside down) you can see that the Chinese one is centered and the original was not... There was my issue, so I don't know how yours fit snug and in place. Yes, the holes always lined up for me, and I thought I had it as well, but it was a tight uneven fit... And I was unable to open/close it, once on...
You wouldn't happen to have any pics of your cap, showing the underside before you put it on? That may explain a lot... Perhaps you got a newer updated one or something? I'm really puzzled and excited at the possibility that the one I have may fit now... I sent you a PM. Hope to hear from you soon. Thanks!
I'LLBUYTHATFORADOLLAR is offline  
post #6 of 78 Old 07-07-2015, 09:04 AM Thread Starter
Senior Member
 
Join Date: Apr 2015
Location: Murrysville, PA, USA. A pleasant, wooded suburb of Pittsburgh.
Posts: 2,160
(Thread Starter)
The Duke's gas tank is an unusual design that uses a tank cover/shroud to provide an aesthetic clean-up for the actual utilitarian-looking plastic tank. The shroud also covers assorted parts hung on the frame, such as the coolant tank, evaporative canister and various electrical bits.

The shroud and tank are separate components and can move relative to one another when unfastened. The shroud, I believe, has a total of 8 fasteners that hold it in place, on the front, back and sides. Each of these fasteners, when tightened, creates tension loads that can alter the position of the shroud relative to the tank. Preventing this from happening is the idea behind the service manual's recommendation to create "special tools" (ie M5 bolts with head cut off at 40mm length and slotted) which are inserted into the gas cap bolt holes on the tank as the bolts themselves are removed. The cutoff bolts then serve as alignment pins to hold the shroud in the correct position relative to the tank. Otherwise, there can be difficulties in re-installing the gas cap after reassembly of the tank/shroud ensemble.

This was James' issue. Somehow his tank shroud became misaligned with the tank, displaced a small distance to the rear. This gave the appearance that the tank filler hole was not in the center of the shroud aperture but situated slightly towards the front of the shroud opening. From James' photo I wrongly interpreted this situation as the actual design of the parts. In fact, it is now clear that the tank shroud opening and the tank filler hole are meant to be concentric. This means a perfectly round part - such as the Chinese gas cap - will indeed fit if both tank and shroud are correctly aligned. The misalignment of those two parts on James' bike prevented James from fitting the Chinese gas cap and led him, quite understandably, to believe that Chinese part was not to spec. James or any other Duke owner who wishes to fit the Chinese gas cap needs to insert the three alignment pins when removing the stock gas cap, loosen or remove the tank shroud fasteners, then maneuver the tank shroud as necessary to ensure that its opening is perfectly concentric with the tank filler hole before tightening down. Then the Chinese cap will fit.
Ubik, mejetski2000 and Hoover like this.

Cheers, Will

"If you don't know where you're going, you might wind up somewhere else."
--Yogi Berra

2015 390 Duke
1980 Moto Guzzi V50 II (becoming a cafe racer)
1984 Moto Guzzi SP 1000
Diploman is online now  
post #7 of 78 Old 07-07-2015, 12:03 PM
Member
 
Join Date: May 2015
Posts: 52
Thanks Will!


Remember Kiddos... When removing your gas cap, use the "Special Tools" (as referred to by the manual)
I'LLBUYTHATFORADOLLAR is offline  
post #8 of 78 Old 07-07-2015, 06:03 PM
Senior Member
 
rippedcb's Avatar
 
Join Date: Apr 2015
Location: Vancouver, Canada
Posts: 276
Will.. that looks awesome! Though i have no issue with my fuel cap.. i'm gonna have to copy you now and pick one up.
malJohann and Diploman like this.
rippedcb is offline  
post #9 of 78 Old 07-07-2015, 09:21 PM
Member
 
Join Date: May 2015
Posts: 52
So after spending the last hour pulling apart my bike and scratching my head, trying desperately to figure out just how it is that it worked for Will and absolutely will not work for me...


I finally came to my senses and realized that I live In F***ing
Comi-fornia!!!!!!! My original assessment was correct when I first tried placing this cap on my bike... No, my sight was not deceiving me and yes, I was most certainly correct when I noted that the new Chinese cap was centered and my original was not... thus making it impossible for this to work on my bike. Now, you may ask yourself, "but, James, what in god's earth does this have to do with you being a California native?"... Well, as it just so happens, California has the most absurd emission laws and once comparing my gas tank opening to the photos on the Duke repair manual, it was obvious that something was a-foot! My bike, since it is a "CA approved" model, has an un-centered tank and additional emissions breathers (or what have you). I am sure now that this is the reasoning for as to why the cap easily worked for Will and WILL NOT work for me (or anyone with a CA Duke). So, long story short, anyone thinking of doing this mod, best be aware, that the cap will not fit on a CA model Duke 390!!! Checkout the pics and look closely at the CA additional breather hoses and cylinder (on the left of the tank)
B7ACKTHORN likes this.
I'LLBUYTHATFORADOLLAR is offline  
post #10 of 78 Old 07-07-2015, 09:30 PM
Junior Member
 
Join Date: Jun 2015
Location: Central California
Posts: 27
So, is it the tank? Or the piece between the tank and the gas cap? Or both, knowing CA.

Running:
'15 KTM Duke390
'06 Ducati Sport1000
'05 Suzuki GSXR750 (2nd one!)
'99 Honda CBR900RR (wife's)

Not running:
'93 Honda CBR600F2

Sold:
'03 Suzuki DRZ400S
'98 Honda VTR1000F
ducdug is offline  
Reply

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome