12425 - Established June, 2013 - all GRiSO, all the time...
 
HomeFAQRegisterLog in

Share | 
 

 Pressure in fuel tank

View previous topic View next topic Go down 
AuthorMessage
jeremyb
Grignapoco
Grignapoco


Posts : 101
Join date : 2013-12-19
Age : 61

PostSubject: Pressure in fuel tank   Tue Aug 19, 2014 6:41 pm

I just put my tank back after removing and totally dismantling it to coat the inside with Epoxy.
Now there's a significant 'whoosh' when I open the fill cap.
I don't think its normal, but this is my first Florida Summer with the bike, so I'm not sure how much pressure should build-up.

The bike is a 2008 US-version GRiSO 1100/2V
I have previously removed the Charcoal vapor canister, and joined the TB ports together with a hose.
I checked the 2 vent hoses at the back of the tank, and they are clear.

Questions:
Is this normal ??
Is there another internal vent in the tank that I might have clogged with epoxy ??
The two vents seem to go up through rigid plastic tubes, and exit in the fill-cap area. Is there a critical way to align the fuel tank surround or gasket or filler cap ?

And - did I do all this for nothing ??   Sad 
I used Caswell 'Dragons Blood' epoxy inside the tank.  We have issues with Ethanol gas here, especially in a hot climate like Florida.
I haven't heard of many issues with the Acerbis tank on Guzzi's, but I got bitten badly by this when I had
my Ducati Sports Classic. Some of those are on their 3rd or 4th tank......I only had 2.  

Jeremy
Back to top Go down
Triman023
Grignapoco
Grignapoco


Posts : 178
Join date : 2014-06-05
Age : 66

PostSubject: Re: Pressure in fuel tank   Thu Aug 21, 2014 10:01 am

I am also getting the whoosh when i open my fuel cap. Once blew some gas out of the tank.
This is a new bike with less than 500 miles on it. Will ask the dealer service what goes. The tank should vent better than that.
Back to top Go down
Pete Roper
GRiSO
GRiSO


Posts : 3783
Join date : 2013-05-29
Age : 59

PostSubject: Re: Pressure in fuel tank   Thu Aug 21, 2014 11:22 am

There was a short run of tanks that had blocked vents, there was a 'Technical Update' campaign for them from memory. I think it was the vent rather than the drain. I'll have a look later.

Pete
Back to top Go down
Phang
Grignapoco
Grignapoco


Posts : 170
Join date : 2013-11-22
Age : 44

PostSubject: Re: Pressure in fuel tank   Fri Aug 22, 2014 12:47 am

here you go...

[You must be registered and logged in to see this image.]
Back to top Go down
Pete Roper
GRiSO
GRiSO


Posts : 3783
Join date : 2013-05-29
Age : 59

PostSubject: Re: Pressure in fuel tank   Fri Aug 22, 2014 2:17 am

Thanks Phang.

Pete
Back to top Go down
jeremyb
Grignapoco
Grignapoco


Posts : 101
Join date : 2013-12-19
Age : 61

PostSubject: Re: Pressure in fuel tank   Fri Aug 22, 2014 3:40 pm

Thanks Gentlemen.
I have a 2008 1100/2V, so probably not covered by that Service Bulletin.
And, its not currently doing this - it 'fixed itself'.    Rolling Eyes    Hmmmmmm

Put compressed air down the vents anyway, and everything is clear.

Jeremy
Back to top Go down
Triman023
Grignapoco
Grignapoco


Posts : 178
Join date : 2014-06-05
Age : 66

PostSubject: Re: Pressure in fuel tank   Sun Sep 28, 2014 5:06 pm

My dealer fixed my tank by finding a pinched hose. It is blissfully silent when I open the gas cap now.
Back to top Go down
jeremyb
Grignapoco
Grignapoco


Posts : 101
Join date : 2013-12-19
Age : 61

PostSubject: Re: Pressure in fuel tank   Mon May 04, 2015 6:11 pm

Well, Bugger me, it's started doing this again - and worse...
Came out to the bike yesterday morning, and a there was a large 'dent' in the tank. I was PISSED
However, opening the gas cap released a lot of vacuum, and the dent pretty much went away. I didn't know painted plastic was that flexible...
Anyway, I obviously have a venting issue. Something (crankcase vacuum after shutdown, temperature changes ??) is generating a strong vacuum.

I removed the gas cap completely, and blew thru the 2 vents both ways and they were clear.

I suspect the problem is with this contraption inside the filler neck:

[You must be registered and logged in to see this link.]


So, has anyone worked-on or had issues with this ??
(For the ever helpful Aussie Gurus - you may not have this thing. My bike is a US-spec 2008 1100, and this looks like some emissions-related crap)

This part of the filler neck covers the vent tube (I think) under this cover is a ball check-valve. I think its to allow over-pressure venting, but not spill in a tip--over ?
The Moto Guzzi Workshop Manual and Parts List is, as always, f-ing useless. It shows the tank cap as one complete unassembled item.
The Guzzi Engineers really should invite the Technical Writers to the pasta lunches where all this stuff is designed and discussed. Then they'll know WTF some of the parts on the bike actually do....
Back to top Go down
Street
Nibbio
Nibbio


Posts : 892
Join date : 2013-05-29
Age : 57

PostSubject: Re: Pressure in fuel tank   Mon May 04, 2015 8:30 pm

Global Weirding!
Back to top Go down
Sponsored content




PostSubject: Re: Pressure in fuel tank   Today at 1:43 am

Back to top Go down
 
Pressure in fuel tank
View previous topic View next topic Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
GRiSO ghetto :: The Ghetto :: GRiSOLOGY-
Jump to: