Ducati.ms - The Ultimate Ducati Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter #1
Hey guys,

I've got my 900ss back together after the "rebuild" but, I'm now having some problems.

The bike idles perfectly for about a minute and a half. then it starts to "studder"

If i put it in gear and try to take off, the bike stalls upon clutch release. It has absolutely no power. It appears to be missing/backfiring on both cylinders. If i let the bike sit for an hour, It runs fine again... for about 2 minutes.

I removed the charcoal canister and plugged the vacuum line. So, I'm sure the tank is venting properly. In fact, With the gas cap open, symptoms remain.

I replaced the fuel filter with an aftermarket (albeit smaller) unit. Could the filter be too small?

Admittedly... i have been running the system without a "bag filter" on the end of the fuel pump, BUT since my tank has been recently restored (por15 treatment (less than 10 miles since treatment)) there shouldn't be any debris in the tank.

any ideas?! I'm really hoping my fuel pump isn't on the way out...
Could any "debris" have made its to the fuel injectors in my "fiddling" with the system. Are the injectors difficult to clean?


Thanks!
 

·
Registered
Joined
·
836 Posts
what reason did you have for not running the pump filter??

you should always run a filter BEFORE the pump to stop damage to it which is sounding like a possibility to your issues.

cam belt timing correct??
 

·
Registered
Joined
·
30 Posts
Discussion Starter #3
well, The PO welded the tank due to the infamous tank rust issue. When the tank was welded, the bag filter was not removed from the tank, therefore, was melted/burned/ruined.

I figured it would alright (for a short time period) considering the tank was freshly "refurbished".

cam belt timing *should* be fine... The only thing I have touched since this "rebuild" has been the fuel system within the tank. The bike ran perfectly before i took the tank apart for repair.

I have a fuel pump lying around from one of my other projects (jaguar xjs). IIRC, it pushes out ~35 psi. Would this be enough for the SS? Im not necessarily looking for a permanent replacement here... but if it solves the problem, I'll know for sure that a faulty pump is my issue.
 

·
Registered
Joined
·
836 Posts
that pump should be fine, i run a V8 fuel pump on my 2002 900s engine, no issues at all and find it runs better than the stock one and was half the price!! lol
 

·
Registered
Joined
·
30 Posts
Discussion Starter #5
Awesome!

This pump fed a 5.3L v12 @6k rpms so, I imagine this .9L twin will be a walk in the park.

I'm still back at my original problem though, I need to find a pre-pump filter/ strainer to protect the pump. I'll stop by auto zone this afternoon and see if I can find something.

Ah... another thing... my jaguar fuel pump is an external unit...
1. Any idea if it would hurt it to be run internally?
2. Could I just run it externally??
 

·
Registered
Joined
·
56 Posts
Running the Jag pump externally would be required, but gives you the chance to do some good fault finding. Try running that pump off a CLEAN small auxilary tank of some sort, then add your smaller filter in the line. That will prove if the filter is too small. If that all goes ok then it can only be your original pump or a kinked line in the tank setup. Would pay to run some fuel through the pump before connecting to the bike to be sure theres no crud in it.

The other thing worth checking first is the return line off your fuel regulator which goes back to the tank. If the pump is working ok and the flow is not restricted by your filter I would have throught this would be flowing fuel back to the tank at idle. Does anybody see any harm in running the bike with the regulators return flowing into a gas can to test this?
 

·
Registered
Joined
·
836 Posts
just dont run it dry and testing it like that will be fine.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #8 (Edited)
okay... I've got it figured out.

With the jag pump plugged in, it runs like a champ. I've linked a video, The video started after the bike was addling for around 10 minutes. I let it run another 5 minutes afterwards just to be sure it ran okay.

Which, in a way... sucks. Hooray for expensive fuel pump replacements:mad:. If I could, I would just run the jag pump externally but, it's too darn big. Plus I would still have the pre-pump-filtering issue.

Anyone have any suggestions for Sub $100 fuel pump replacements. I have a few friends that have upgraded their turbo car fuel pumps but, most of them have already given away their OEM Pumps.

 

·
Registered
Joined
·
241 Posts
1 - 9 of 9 Posts
Top