I've managed to get a small fuel pump and aluminium holder for the 4RT. The only thing I need is the "bulb" which I assume is some kind of expansion tank between the pump and outlet. Is the bulb needed or can I just put a tube from the pump to the outlet?

The bulb is a high pressure fuel filter. It's there to keep finer particles that may have passed through the teabag inlet filter from getting to the injector.

There's a similar Honda part on other models. Below is an image of one (taken from an eBay ad) that's common to larger EFI street bikes.

This one looks similar to the part used on 4RT fuel pump assemblies. But it might be a little larger based on the scale. However, there could be some perspective error that makes it hard to get an accurate sizing in the image. Sorry, but I don't have a 16900-MBG-013 to compare directly to a 4RT filter, so can't tell you for sure. You may want to check with local Honda dealers to see if they have one in stock for comparison.

Future Trial sells another filter for the high pressure side, it appears to be made by Mahle but I can't make out a part number. It's got a plastic body, and I haven't been able to look into it to see what the pressure rating is.

Note that fuel hose on the high pressure side is also reinforced.

If you do find the 16900-MBG-013 fits nicely, or if you find a suitable replacement, please report back. Thanks.

 

Edited May 1, 20179 yr by sportsawyer

Hi and thanks for the comprehensive reply. It might take me a couple of weeks to reply because I'll probably fix it into my flat tank. I'll let you know how it goes. 

Cheers

I looked into the Mahle filter a little more. Future lists it as 30mm diameter. There's a Mahle filter for 4 different Ducati models 2007-2012 that's 30mm and looks the same as the one Future sells. The Mahle number is KL97 and it's a replacement for Ducati part 425.4.015.1A. On Ducatis, this filter is used in-tank on the pressure side, same as with the 4RT. So it should work, but you may need to look into it further if you're thinking of going that way. It has straight barbs from each end, so would need more hose bend (and hose that will take the bend) or a barbed u-bent piece. See the Future fuel pump assemblies for an idea.