Gas Cap problems

Post by **jcslocum** » Sun Jun 11, 2006 12:14 am

A funny thing happened on the way to fill up today. The gas cap would NOT come out of the filler hole. It appears that the black rubber/plastic thing has expanded for some reason and would no longer fit thru the hole. I had to come home and remove the filler assembly in order to squeeze the 2 "ears" in far enough to pull the cap out.

I hooked up a small grinder and had to remove a significant amount of material to make it so that it just fit and could be removed.

I'm guessing that the Ethanol mixed into the fuel has probably caused the rubber/plastic to swell up some. Has anyone else encountered this problem??

BikerBard · Post by **BikerBard** » Sun Jun 11, 2006 3:53 am

Wow, funny you should mention this. I had the exact same problem tonight! I've had this Duc since '02 and have NEVER had trouble getting the cap off. Tonight I like to have never got the freaking thing out of there. I thought I was just going crazy.

:screwy:

delagem · Post by **delagem** » Sat Jun 17, 2006 4:14 am

Well, I'm no expert on Ethanol, but I do know that both of you live in areas controlled by the EPA's strict emissions laws, and just in the past few weeks is when they switched the gas from the lighter, 9.0 rvp gas to the summer grade, heavier, 7.8 rvp gas. If I get a chance I'll look at the lab spec's and see what's different in the gas between the two grades.

delagem · Post by **delagem** » Wed Jun 21, 2006 2:51 am

Ok, well, I looked at the lab spec sheets and I now think I'm barking up the wrong tree. Not much difference betwen 7.8 and 9.0 rvp gasoline.

Notable differences:
Specification normal 9.0 summer 7.8
Aromatics 37% 32%
Benzene .65% .70%
Gum (mg/l) 2mg <.5mg
Olefins 13.7% 14.3%
Sulfur (ppm) 36ppm 48ppm

The spec's I'm looking at are for conventional gasoline, not reformulated. Either of you guys still in a RFG area? I don't know as though anyone is using MTBE anymore, but if you are, that's your problem. MTBE plays havoc on plastics and conventional rubber. Eats the valve seals on the ship, and hauling gasoline is what we do! Certainly not something that Ducati could have thought of 20 years ago...

But I thought MTBE was a half-assed fix for poor air quality during the winter, not summer? I believe that either MTBE or Ethanol has to be labelled on the pump...

Post by **paso750** » Wed Jun 21, 2006 8:10 am

I remember a similar problem disussed either here or in the mailing list longer time ago. The gas cap wouldn`t come off due to underpressure building up in the tank for some reason. Let`s see if I can find it.

G.

fasterdammit · Post by **fasterdammit** » Thu Jun 22, 2006 1:57 pm

paso750 wrote:I remember a similar problem disussed either here or in the mailing list longer time ago. The gas cap wouldn`t come off due to underpressure building up in the tank for some reason. Let`s see if I can find it.

G.

Blocked vent tube?

Post by **jcslocum** » Thu Jun 22, 2006 4:15 pm

No, no, no, no. You're heading in the wrong direction. You've left the road and driven into the cornfield!

This is NOT a vacuum issue. This is a mechanical interference, where the black plastic thingy would not fit thru the aluminum plate even AFTER it was removed from the tank.

750pheonix · Post by **750pheonix** » Thu Jun 22, 2006 10:32 pm

I was going to offer the spare cap i have but i realised that wouldn't change anything... the cap you have now is the original size anyway

the rubber seal has been altered to make it impossible to place the cap back in to be able to lock it in place...

We don't have the same problem in the UK, the petrol is made up a little differently.

spaynenda · Post by **spaynenda** » Tue Jun 27, 2006 5:50 am

Just passed 27,000 miles on the odo this weekend on a run up to Santa Barbara from my home in San Diego area, and had difficulty removing the gas cap, as some of you described. This is not the first time, although until this spring I've not had the problem at all.

At first I suspected misalignment of the plastic bit with the actual cap, but on closer inspection, the plastic part does appear to have gotten slightly larger.

I'm not much of a wrench, but perhaps a gentle sanding of the plastic surface without changing the contour would solve the problem, as suggested by our man jcslocum.

My only question is, should the surface be finished back to smooth after removing the material? For some reason, I worry that rough surface may accumulate nasty stuff, need to seal to somat or some such other mysterious thing.

Post by **jcslocum** » Fri Jun 30, 2006 1:45 am

The seal is made by an o-ring up higher and not by the plastic thing. I just filed it till it fit and went riding.

I plan to find something to seal the tank and take the cap off this weekend and leave it in the sun to heat up and dry out. Maybe that will help shrink it back to it's original size.

I'll let you know how I make out.

BikerBard · Post by **BikerBard** » Sun Jul 02, 2006 4:22 am

Would different brands of gas make a difference? Maybe it's just my imagination, but it seems worse when I use Exxon.

DG

delagem · Post by **delagem** » Sun Jul 02, 2006 1:27 pm

Probably not; it's a sad truth of my industry that when you buy Exxon, or Sunoco, or whatever, you're just getting whatever gas they happen to have on hand. We bring in 12,000,000 gallons of gas every week to south Florida, and less than half of it goes to Citgo. We pump it to whoever needs it; they just buy it from Citgo, or trade it; i.e. pay it back when their contracted ship comes in.

There are only a few grades that are guaranteed proprietary. Sunoco Ultra 94, and Amoco Ultimate are the only two I can think of off the top of my head.

If you wanna really be annoyed, let me tell you about when tankers all had common pumping systems, and at the end of a discharge, all other grades were stripped into the Regular. So your regular had all the tank bottoms (ie sludge) and all the diesel, jet fuel, etc. mixed in with it.