Hi all,

​​​​​​I'm renovating my old CBR 900 RR SC28 from 1992. Upon disassembly I'd noticed how the fuel filter was placed between the fuel pump and the fuel intake on the carbs. However, when reading the manual, it looks as though the filter is to be placed between the petcock and the fuel pump. Which of the two is the right way? Before or after the fuel pump?
​​​​​​
Best,
Nikolai from Denmark

 

Personally I would alway go for before the fuelpump, because then also the fuelpump is protected against debree.

 

Thank you very much, Chris.

Have you done so on a similar bike?

 

It should be placed between the petcock and the fuel pump. This is a standard setup.

 

I have not done a similar bike but I have seen some variations. And there are arguments to be made for both.

Arguments for placing the fuelfilter before the pump:
- Your pump remains clean
- The rest of the fuelsystem remains cleaner.
- The filteringsurface is generally bigger and therefore one has slightly more fuelpressure.

Arguments for placing the filter after the pump
- Easy replacement
- No vacuum bubles because the pump sucking through a filter
- Fuel these days is very clean and the pump can handle a tiny bit of contaminents (see me avoiding the word debree)
- Above is only because it is a low pressure pump. If you have a serious fuelpump for example like a diesel fuel pump it cannot handle contaminents.
- If the pump blows, the rest of the fuel system remains still clean.
- If the fuelfilter is full fuelpressure drops and the engine won't run proper. Instead of having the chance that the pump runs dry because of vacuum.

So, hamlin6 is reasonably right that it is the standard setup.
And again, I can make arguments for both setups.

Most important: mount a fuel filter