Tank Vacuum

fingerpuk · May 4, 2015

Hi all.

I've only done 220 miles on my new 821 so this may be normal, but all the threads I find argue about it. Maybe we will too. I am building up enough tank vacuum to make it hard to remove the cap, and when I do I feel the tank moving/swelling back to size. Is this normal or should I hunt for a pinched hose?

I have the UK version so no box to remove.

Cheers.

ferdi · May 4, 2015

this is not normal. seems your vent is not working or clogged

fingerpuk · May 4, 2015

Bugger. Thanks though. Where is it, the service manual I have has nothing listed under hose, fuel, or breather.

fingerpuk · May 4, 2015

Have found what I think is the breather hose, it was going through a clip with two others and was slightly pinched. Not enough to cause this I think, but I'll ride it again tomorrow and keep an eye on it. I'm not experiencing any odd fuelling issues like others do. It's booked in for it's first service soon so I'll ask them to take a close look.

kuksul08 · May 4, 2015

My bike "moo"s at me all the time so i know its venting properly.

zibbit u2 · May 4, 2015

If this happens it's because the evap canister vent line is pinched. 2 solutions to this problem are;

1. Delete the Evap system

2. Buy heavier duty vent line for the canister.

AussieHyper · May 4, 2015

kuksul08 said:
My bike "moo"s at me all the time so i know its venting properly.

Does this happen when you turn the bike off and it's cooling down? If so I thought this 'mooing' was the cooling system sucking fluid back into the radidator from the over flow tank and not a noise coming from the fuel tank vent.

Any thoughts?

ferdi · May 5, 2015

zibbit u2 said:
If this happens it's because the evap canister vent line is pinched. 2 solutions to this problem are;

1. Delete the Evap system

2. Buy heavier duty vent line for the canister.

fingerpuk said:
....................
"I have the UK version so no box to remove."
........................

seems to be another problem

fingerpuk · May 5, 2015

Took the tank panels off, checked the hose and it all looks to be ok but did a partial re route just to be safe. I can blow through the pipe fine, it makes a odd fart sound which I guess is the valve. I'll take it out for a ride now and see what happens.

fingerpuk · May 5, 2015

Did 120 mils on it today, no problems at all. Must have needed that re-route.

kuksul08 · May 5, 2015

AussieHyper said:
Does this happen when you turn the bike off and it's cooling down? If so I thought this 'mooing' was the cooling system sucking fluid back into the radidator from the over flow tank and not a noise coming from the fuel tank vent.

Any thoughts?

Nah it will moo any time there is a temperature change. If I just wheel it into the sun and it warms up it will moo at me the whole time. Then as it cools down it will moo more.

appliance821 · May 5, 2015

First time I noticed it, it was dead of night, I was I was camping and I didn't know what it was. Grabbed a headlamp and an axe ....

Tank Vacuum

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