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Fuel cap issues (leaking)

Posted: Thu Aug 10, 2017 9:45 am
Author: Viktor Larsson
Hey guys, long time no see.

The Mk.II project is on the road and it's a really pleasant ride with the new suspension, wheels, brakes and all that. But I still have an issue with the bike and it's bothering me. A lot.

So when I was rebuilding the bike I removed the stock fuel tap from the tank and welded on a new fitting for a Pingle fuel tap. Now I have the issue of fuel seeping out the fuel cap, presumably due to pressure building in the tank.

What's the remedy here? The tank is freshly painted with new decals so I'd hate to go at it with a drill and weld on a small tube and run a line for ventilation (would cost quite a bit...). Do I have any options besides doing that? Anything? :|

Re: Fuel cap issues (leaking)

Posted: Thu Aug 10, 2017 2:18 pm
Author: Julian_Boolean
Blocked vent hole in the existing cap?

Re: Fuel cap issues (leaking)

Posted: Thu Aug 10, 2017 5:43 pm
Author: Viktor Larsson
Julian_Boolean wrote:Blocked vent hole in the existing cap?


There is a vent hole in the stock cap? :shock:

I think I need to take a closer look at that. Might be where the issue is if that's the case.

Re: Fuel cap issues (leaking)

Posted: Thu Aug 10, 2017 6:42 pm
Author: z1bman
i presume you have checked the two small o rings that seals the tank cap screws ?

Re: Fuel cap issues (leaking)

Posted: Thu Aug 10, 2017 6:58 pm
Author: Viktor Larsson
z1bman wrote:i presume you have checked the two small o rings that seals the tank cap screws ?


Might have to take a second look at this too.

Re: Fuel cap issues (leaking)

Posted: Fri Aug 11, 2017 9:24 pm
Author: Viktor Larsson
Took the fuel cap apart and the breather seems to be fine. I just think it's really small but I guess it is enough since it has worked before. Cleaned out a bit of dirt from it. Also put some sealant in the threads for the screws. Hopefully it should be better now.

I'll report back tomorrow.

Re: Fuel cap issues (leaking)

Posted: Sun Aug 13, 2017 12:17 am
Author: Viktor Larsson
Took the bike out for a bit of a longer ride today after fiddling with the fuel cap yesterday. When taking it apart, it seems like one of the grooved rings that makes up the ventilation was fitted upside down and as such did not provide any ventilation whatsoever.

Thread sealant in the threads for the screws and the leaks are no more. Really happy to have sorted that out... thanks for the suggestions guys. :wink: