Author Topic: fuel tank ports  (Read 349 times)

Offline Dirk_S

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fuel tank ports
« on: February 10, 2019, 11:45:33 AM »
TL;DR: what do all the fuel ports do on my V7 II?

My previous bikes were 70s carbureted machines, so my knowledge is based off them. That said, read on for a nice chuckle, lessons learned, and questions to ask...

Recently, before a trip to Canada, i bought an INNOVV dual dash cam. Hooked the + and - wires up, couldn’t figure out where to hook the accessory wire to (Guzzi working diagram was hard to read), and made a random choice to solder in with a yellow wire that’s part of a harness near the battery under the seat. Dash cam worked great, but a few weeks later, I found the battery was draining - didn’t help when I left the engine cutoff switch ON <cough>. Battery needed to be replaced.

* Bought a lithium-iron battery, accidentally produced an arc because I always forgot which terminal to hook up first (I remember now!). Battery still holds A charge, but I wondered if it shorted too much.

* Bike started and ran for a while, but again began to have starting issues. I figured I had destroyed that lithium-iron battery or was hooked up to a permanently live feed with the AUX.

* Disconnected the dash cam setup; will address it again this spring.

* Bought a new LEAD ACID battery (not making THAT potentially expensive mistake twice!)...... Wrong size battery.

* Bought the CORRECT size lead-acid battery (not making THAT mistake twice!). Installed the battery, bike wouldn’t start.

* Feared I might’ve doofed up a relay or the starter motor!

* Checked the fuel tank. Low. Dumped some gas in. Still no start.

* Remembered that the one hose nearest the seat tends to pop off when I lift the tank. Lifted the tank - saw it was disconnected!

* Connected the hose, gave a few starts, and bammo! Back in business! The hose was short, dry, and cracked - decided to buy a new line. Assumed it was a fuel line.

* Replaced the old hose with new, longer fuel line hose. Realized it wasn’t a fuel line but a vent port.


I hope that was at least mildly entertaining. I tend to learn best from (sometimes expensive) mistakes.

2 QUESTIONS, though:
  • is it a legitimate fact that the bike won’t start if the vent hose is disconnected? How is this so? Is there a sensor?
  • there are a bunch more ports and hoses than I’m accustomed to, and I can’t find literature to what they all specifically are. Directing me to this knowledge or providing insight would be greatly appreciated!

Footnote: bike is currently running on lithium-iron battery with a battery tender. Will continue to monitor it. At least I have a lead acid battery backup!
Current:
‘16 Guzzi V7 II Stone

Previous:
‘77 Kawasaki KZ400 Special
‘78 Honda CX500 Standard
‘80 Honda CX500 Deluxe
‘11 Suzuki TU250X

Offline guzzisteve

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Re: fuel tank ports
« Reply #1 on: February 10, 2019, 12:37:18 PM »
1. It should make no difference plugged in or not
2. You should get familiar w/all on your bike, here is some info

http://www.thisoldtractor.com/mg_manuals/workshop_manual_v7-ii-abs_en.pdf

You can disconnect the EVAP system and run tank vent and gas cap well drain strait down under bike.
Parts book page 20 & 43

http://www.guzzitek.org/parts_list/pb/750/V7_II_SpecialABS_USA-CND_2016_022016_PL(GB).pdf
« Last Edit: February 10, 2019, 12:43:14 PM by guzzisteve »
"Pray through Carlo & your bike shall be healed"
Location: Planet Earth

Offline Dirk_S

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Re: fuel tank ports
« Reply #2 on: February 10, 2019, 08:45:18 PM »
Thanks! I already have the service manual, but didn’t see anywhere that pointed out the various ports. In fact, the parts fiche only calls out one port.
Current:
‘16 Guzzi V7 II Stone

Previous:
‘77 Kawasaki KZ400 Special
‘78 Honda CX500 Standard
‘80 Honda CX500 Deluxe
‘11 Suzuki TU250X

Offline Howard R

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Re: fuel tank ports
« Reply #3 on: February 11, 2019, 08:35:53 AM »
1) It is purely coincidental that the vent hose was disconnected when the bike wouldn't start.  In fixing the vent hose, you moved/bumped/reconnected whatever was the problem so it works now, until it doesn't again.

2) I'm not familiar with your particular model, but I think it has the fuel pump inside the tank.  If that's the case, there should be one port from the tank to the injectors.  This port/hose will be the largest one, OD probably as big around as your thumb (or maybe a little more) and it will probably look like it's capable of standing up to a pressure of 3 bar (45 psi) because that's about where fuel injection systems work. The vent hose you found should be not much larger than a pencil, and it doesn't have to hold any pressure.  Depending on the design of the gas tank cap, there might be another drain hose (similar in appearance to the vent hose you found) for a "moat" around the neck of the gas tank, to allow egress of water from washing or riding in the rain, or any spillage/overflow when refueling.  That one should just go to atmosphere.

Hope this helps.

Howard
Littlestown, PA  USA

1996 Sport 1100
1998 Centauro

MGNOC # L-707

Offline Dirk_S

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  • Location: Dover, NH
Re: fuel tank ports
« Reply #4 on: February 11, 2019, 09:40:29 AM »
Thanks for assuring me of the probable coincidence. I wondered if that might be the case. I’ll try to take a pic of the underside sometime soon.

 By the way, Howard, I’m originally from Spring Grove, PA - not far from you at all! I visit home at least once a year.
Current:
‘16 Guzzi V7 II Stone

Previous:
‘77 Kawasaki KZ400 Special
‘78 Honda CX500 Standard
‘80 Honda CX500 Deluxe
‘11 Suzuki TU250X

Offline guzzisteve

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Re: fuel tank ports
« Reply #5 on: February 11, 2019, 12:16:33 PM »
Should just be 2 small lines besides the main fuel disconnect. If you remove fuel cap & blow air up it will come out the drain by cap or the vent. Easy to figure out which is which.
"Pray through Carlo & your bike shall be healed"
Location: Planet Earth

 


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