Ducati Monster Forum

Moto Board => Tech => Topic started by: BlackKat on October 31, 2010, 04:33:45 AM

Title: fuel line size/spec on carb'd monsters
Post by: BlackKat on October 31, 2010, 04:33:45 AM
G'morning guys,
As some have you have seen on my other posts, the previous owner of my bike did many things wrong...One of my winter projects is the clean up the fuel lines a bit. The other day I wanted to measure them and discovered a couple sizes on the bike. I presume this isn't correct. I.e., 1 size going into the filter and a different coming out...

Does anyone know the correct size fuel line for a 99 750?

Cheers!
Title: Re: fuel line size/spec on carb'd monsters
Post by: Howie on October 31, 2010, 04:49:24 AM
5/16 fuel line, but before you do anything try to determine why the sizes are different.  For example, some of the aftermarket fuel filters that supposedly fit have a 1/4 inch nipple.  Same with some aftermarket fuel pumps.  1/4" line will flow enough fuel for your bike.
Title: Re: fuel line size/spec on carb'd monsters
Post by: ducpainter on October 31, 2010, 04:50:37 AM
The OEM lines were slightly smaller going into the filter so that piece is probably original.

Most people use 5/16" id for replacement.

howie beat me... ;D
Title: Re: fuel line size/spec on carb'd monsters
Post by: junior varsity on October 31, 2010, 05:15:59 PM
5/16" fuel capable lines, here's an example of some i've used before and i like because they match the fren tubo oil cooler lines and brake lines I have on a M900:

(http://www.jegs.com/images/photos/800/865/865-29390.jpg)

http://www.jegs.com/i/Spectre/865/29390/10002/-1 (http://www.jegs.com/i/Spectre/865/29390/10002/-1)
Title: Re: fuel line size/spec on carb'd monsters
Post by: The Mad King Pepe' on October 31, 2010, 08:00:37 PM
Don't know if it's the same buy on my 2001 M750 I have 5/16 up to the pump and then 1/4 to the carbs.
Title: Re: fuel line size/spec on carb'd monsters
Post by: junior varsity on November 01, 2010, 07:06:58 AM
Mine were originally 5/16" and 1/4", I didn't like this. Now its all uniform.
Title: Re: fuel line size/spec on carb'd monsters
Post by: koko64 on November 04, 2010, 07:38:20 PM
I'm running 5/16 all the way, it's an OCD thing :D
Title: Re: fuel line size/spec on carb'd monsters
Post by: Duck-Stew on November 04, 2010, 08:13:41 PM
Quote from: Pepe' on October 31, 2010, 08:00:37 PM
Don't know if it's the same buy on my 2001 M750 I have 5/16 up to the pump and then 1/4 to the carbs.

+1 on this.  I have 2 M900's in the shop now and they're both running lines as above.  The nipple out of the vacuum petcock is smaller than I feel comfortable putting a 5/16" line on (same goes for the inlet and outlet of the fuel pump and the inlet to the carbs....)
Title: Re: fuel line size/spec on carb'd monsters
Post by: dlearl476 on November 08, 2010, 12:11:59 PM
Quote from: Duck-Stew on November 04, 2010, 08:13:41 PM
+1 on this.  I have 2 M900's in the shop now and they're both running lines as above.  The nipple out of the vacuum petcock is smaller than I feel comfortable putting a 5/16" line on (same goes for the inlet and outlet of the fuel pump and the inlet to the carbs....)

Same with my '99 M900.  After my cracked line leaked 2-3 gallons of gas in my garage, I replaced all of it and binned the vacuum petcock.  Because the line out of the tank is larger than the one going to the carbs, I simply bought an aftermarket fuel filter with a 5/16" inlet and a 1/4" outlet.