Ducati Monster Forum

Moto Board => Tech => Topic started by: greenohawk69 on January 23, 2017, 08:11:17 AM

Title: FUEL HOSE SIZE - 97M900
Post by: greenohawk69 on January 23, 2017, 08:11:17 AM
What is the size of the fuel hose that is north of the fuel pump?
Title: Re:
Post by: greenohawk69 on January 23, 2017, 08:23:31 AM
Found a different thread:  http://www.ducatimonsterforum.org/index.php?topic=43932.0

That states it is 5/16" to the vacuum petcock (vp) and 1/4" from the vp to the pump.

A member stated they removed the vacuum petcock. What are the pros and cons to this?
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Speeddog on January 23, 2017, 08:59:20 AM
Not sure which direction North is on the bike.....

I've found that by this time, the youngest VP on a Monster being 16 years old, many of the vacuum petcocks are not working properly.
Not opening, or not closing, or leaking from the fuel to the vacuum side.

Manual petcock you've got to remember to turn it on and off.
Title: Re:
Post by: greenohawk69 on January 23, 2017, 09:20:17 AM
The pump is lower or south of the vacuum petcock. I'm referring to the hose from the pump back up towards the petcock and gas tank.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Speeddog on January 23, 2017, 07:15:12 PM
Pump to petcock is 1/4" or thereabouts.

Buuuuuutttt.... it's a preformed hose, it does a very tight bend to connect to the bottom of the fuel pump.
Over-the-counter fuel hose won't make that bend.

You may be able to re-route some regular hose and get it to work.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 23, 2017, 07:56:16 PM
Quote from: Speeddog on January 23, 2017, 07:15:12 PM
Pump to petcock is 1/4" or thereabouts.

Buuuuuutttt.... it's a preformed hose, it does a very tight bend to connect to the bottom of the fuel pump.
Over-the-counter fuel hose won't make that bend.

You may be able to re-route some regular hose and get it to work.
Shouldn't we be concentrating on getting rid of a vacuum petcock on a 20 year old bike?

Then a preformed hose is no longer an issue. ;)

Title: Re: FUEL HOSE SIZE - 97M900
Post by: Speeddog on January 23, 2017, 08:24:48 PM
Well, I've eliminated the VP on my M750, and have a manual petcock spliced into the OEM line that formerly went from the VP to the pump.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Howie on January 23, 2017, 11:00:44 PM
This is what I did on my 750.  Got rid of the preformed and got the hose to the carbs away from the heat.

(http://i298.photobucket.com/albums/mm276/hlep2890/bike/IMG_0422.jpg) (http://s298.photobucket.com/user/hlep2890/media/bike/IMG_0422.jpg.html)
Title: Re:
Post by: greenohawk69 on January 25, 2017, 11:40:19 AM
Have some questions as I can't quite make everything out in the picture:

1) Are you running a 5/16" fuel line from the fuel filter straight to the carb (bypassing the vacuum  petcock and the fuel pump)? Any issues doing this? I would be using a shutoff valve between the filter and carb...probably in a location somilar to Howies'.

2) If the fuel pump is bypassed, does anything have to be done to it (other than plugging inlet / outlet)?

3) The vacuum hoses from the VP to the manifold and from one manifold to the other - are these removed? If yes, are the outlets on the manifolds plugged?

Title: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 25, 2017, 11:51:26 AM
If you eliminate the pump you won't ever be able to use all the fuel in the tank. There will always be about 1/3 left due to the height of the tank outlet and the carb inlet. I wouldn't recommend eliminating the pump.

If you remove the VP you remove the vacuum line and you can use a vacuum cap on the nipple, or a threaded plug in the manifold with the nipple removed.
Title: Re:
Post by: greenohawk69 on January 26, 2017, 09:14:25 AM
Can a 5/16" fuel hose be used from the fuel filter to the pump? Or just stay with the 1/4"? Some have mentioned the 5/16" won't make the bend to the pump. The 1/4" fuel line can make the bend?

In the above link I included, a 5/16" SS flexible hose has been used by one owner.

Also, where do individuals install their shutoff valve? I was installing mine after the petcock and prior to the pump.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 26, 2017, 03:06:41 PM
You should remove the vacuum petcock and install a manual shutoff between the filter and pump where you can reach it.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: koko64 on January 26, 2017, 07:01:03 PM
Listen to the man. ;) That vacuum tap will sooner or later let you down. Also, the occasional carb flooding symptom can be dealt with by a quick 20 second off then back on of an easy to reach manual tap with the motor running in most cases. It also helps with servicing, tank draining, etc. Handy to have.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Speeddog on January 26, 2017, 07:22:29 PM
This is where I put mine on my M750.
A small piece of adhesive-backed foam rubber from a Shorai battery kit, and a ziptie to keep it roughly in place.
Rerouted the OEM hose from the fuel pump up to it, I'm pretty sure I used the remainder of the OEM hose to continue up to the filter.
Functions as a not-so-quick disconnect for the tank, as well.

(https://c1.staticflickr.com/1/743/32166506000_dfaefd5c3d_b.jpg) (https://flic.kr/p/R1rKz3)
Title: Re:
Post by: greenohawk69 on January 26, 2017, 07:49:13 PM
I've already installed a quick disconnect from the tank to the filter.

I get removing the petcock, thanks.

Was going to install shutoff valve before the pump, but...I bought a 5/16" and it appears that I need a 1/4".

My question is - does the fuel line to the pump need to be 1/4" or can you also use 5/16"?

The flexible 5/16" SS fuel line with magna clamps from Jegs was used by another individual (from the link to another thread).

Title: Re: FUEL HOSE SIZE - 97M900
Post by: Howie on January 26, 2017, 07:55:30 PM
All your fuel line should be 5/16.  Where is this 1/4" hose?  Sounds like vacuum hose to me.
Title: Re:
Post by: greenohawk69 on January 26, 2017, 07:57:58 PM
After the vacuum petcock to the fuel pump. Tried fitting the shutoff valve and it was really tight...and stopped. I'll try again. Thanks.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Speeddog on January 26, 2017, 08:11:41 PM
The valve I've got (shown in my pic) is a 5/16" Motion Pro part.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: greenohawk69 on January 26, 2017, 08:18:42 PM
Have one also. (https://uploads.tapatalk-cdn.com/20170127/a48de279b181e49c9a6447b6ef63737a.jpg)
Title: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 27, 2017, 03:33:44 AM
I don't exactly remember, but I believe I used a 5/16" petcock and line.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: Howie on January 27, 2017, 03:49:38 AM
5/16 throughout on my old 750.
Title: Re: FUEL HOSE SIZE - 97M900
Post by: greenohawk69 on January 28, 2017, 08:02:44 PM
Here's a picture of the fuel line from the vacuum petcock to the fuel pump (97 M900).

OEM is on the left (1/4") and 5/16" fuel line on the right.

I've replaced the OEM formed fuel line with 5/16" hose and secured with fuel injection commectors.

Am I better off with the 1/4" fuel line or ok with the 5/16"?

(https://uploads.tapatalk-cdn.com/20170129/401efa4c134f041a43de9e96d7652937.jpg)
Title: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 28, 2017, 08:07:18 PM
Whatever doesn't leak. ;D

What size is the line from the filter to the petcock?
Title: Re: Re: FUEL HOSE SIZE - 97M900
Post by: greenohawk69 on January 28, 2017, 08:09:39 PM
Quote from: ducpainter on January 28, 2017, 08:07:18 PM
Whatever doesn't leak. ;D

What size is the line from the filter to the petcock?
That's what I was going to go with. Lol

5/16"...why I assumed it was to the fuel pump.  :o
Title: Re: Re: FUEL HOSE SIZE - 97M900
Post by: ducpainter on January 28, 2017, 08:16:03 PM
Quote from: greenohawk69 on January 28, 2017, 08:09:39 PM
That's what I was going to go with. Lol

5/16"...why I assumed it was to the fuel pump.  :o
It'll be fine with 5/16". No real pressure...tighten the clamps.

It'll be fine. ;D ,,,it's a 16th.