Ducati Monster Forum

I wanted to ask a general question on the fuel pump arrangement / performance and reliability of the S2R vs S4R fuel pumps.

Most probably know the S2R is a circular base which has both the fuel pump and quick disconnect fuel lines.  The S4R has all that as well, but was also used on 848 / 1098 etc superbikes. . . .so. . is the oval version any more reliable than the round base S2R?  I am assuming there could be a difference in pump pressure due to demand for 4V vs 2V engines.

Last, I have an S2R.  Would it be at all possible to fit an S4R tank onto my S2R?  Only asking since I'm wading through the fuel pump and fuel tank issues, and considering any possible 'upgrade path' while I have things torn down.

Thanks in advance

Afaik, all stock bikes (except the race homologation SBK Rs) ran the usual 43.5 psi fuel pressure. The pumps appear to be the same.

I've noticed zero difference in reliability of the different flange styles.
Everything except the wiring is very reliable in my experience.

Converting between steel and plastic tanks is costly, as almost none of the components are shared.

S4Rs/t plastic tank is smaller capacity than S2R tank.

Thank you - that’s the info I was looking for. I had a hunch that the S2 & S4 pump ‘plates’ were the main difference but I’m not able to compare them side by side.

I’m talking with a company that makes aluminum  fuel tanks. They’re familiar with the S4 version. No, it’s not a cheap conversation so I wanted to ask ahead of time if there is a benefit for the oval S4 design.

Cost and availability might be a consideration. It seems the round flanges go for a lot more money on eBay. $600 compared to $200 or so.

I thought I read somewhere the S4r used an oval to make more room for the extra stuff (airbox etc.) under the tank? Maybe why the S4r holds less fuel? I'm only guessing as I have the S2r.

Yes

I have a 2005 S4R with a metal tank.  Is the metal tank stock?  What year did they switch to plastic?

Derek V

Yes. First year S4R had a steel tank from the factory.

Thanks!

 ???

Both S2R & S4R/S have the airbox & battery under the tank in the same spot and in the same configuration. I'm using the chopped airbox lid from my S2R on this bike (S4RT) so I know it's not because the airbox is bigger. Is the airbox deeper or does it sit higher? Not immediately understanding why the tank capacity had to be decreased.

Larger heads  ;)

S2R and S4R, yes.

S4Rt/s is different layout of battery/ECU/etc and different airbox