Gas Leak?

[Randyjaco]

As I get more familiar with my RT, I am underwhelmed with its gas mileage. I was noticing today that frequently when I stop for a traffic light I smell raw gas. I have pulled to the side of the road, I don't see any liquid evidence of a leak, so I presume it is a slow leak/leaks. I checked the area around the filler neck and it is dry. Before I start removing tupperware, I'd like to find a dye or something that would indicate where the leak might be once the gas dries up. Any suggestions on what I could use? Or does an RT just smell like gas when you stop it? 

Thanks

Randy

2017 RT

[Geekmaster]

Randy, I noticed the same thing with my 2014 RT.  I could easily replicate it at home in the garage after it had sat for a couple days.  With 3/4 or a full tank, simply rocking the bike side to side and back and forth, and I could smell gas.  When the tupperware was removed to replace the air filter at my 12k service, I noticed that there was evidence of leakage around (underneath) the gas cap assembly.  I removed the gas cap assembly and ordered a new gasket.  However, that did not fix the issue.  As I looked at it closer, I noticed that my gas tank was slightly warped around the filler neck hole.  So what I did was to take some of the Permatex (link below) and seal underneath the filler assembly.  Please note that I let the Permatex sit for about 30 minutes before reassembling.  And then it only worked after about 24 hours of sitting.  

 

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant-2-oz/

 

If I were to do it again, I might consider this Permatex product instead:

 

https://www.permatex.com/products/gasketing/speciality-gasket-makers/permatex-motoseal-1-ultimate-gasket-maker-grey-2-7-oz/

 

But what I did seems to be working, so I'm going to keep it as is until/unless it fails.

 

I did read about another RT owner who just had to replace the rubber gasket.  So, if you take yours apart, check to see if the tank is warped at all.  If it's warped, you'll need to use some sort of sealer (gas-resistant).  Otherwise, a new gasket from BMW may fix it (it was about $8).

 

Let us know how you make out.

[Randyjaco]

Thanks, sounds like a likely culprit and solution

[Paul De]

3 hours ago, Geekmaster said:

 Please note that I let the Permatex sit for about 30 minutes before reassembling.

Yes.  It is very important to let the form a gasket material to set up some before tightening down completely. If you try to fully tighten the the mating parts before the form a gasket has set up some you'll squish it out of the gap you are trying to seal and will likely still have a leak.

[strataj]

The above may be your problem but I also found it's easy to overfill, look at your manual to see the top level, if overfilled you will smell gas and then after some use no more odor.  I would think if vapors leaked from a warped tank that would persist. 

[Rinkydink]

This may be a stupid question but if it was indeed just slightly warped could you try 2 gaskets before trying to use the permatex?

[realshelby]

Before you get into mechanical stuff....know that the gas cap on these can seem to be closed but is in fact not fully latched. Put some grease/vaseline on the latch surfaces and a very small amount of lube on the stuff you can get too where the hinges and stuff are. Your symptoms are exactly what I used to see in my RT. 

[Geekmaster]

5 hours ago, Rinkydink said:

This may be a stupid question but if it was indeed just slightly warped could you try 2 gaskets before trying to use the permatex?

 

I do not think that 2 gaskets would fix it (at least not in my case).  Plus the gaskets themselves have a small ridge around to help in sealing, which would likely not seal if they were stacked.