in"sight" to the 990 Fuel pump

i managed to open up the fuel pump on my '07 990S and give it a thorough look inside. It looked good except for some grains of dirt and a few metal looking filings, which were filtered by the dual filters (good - they are doing the job). Of course the pump O-rings were damaged (even before i opened removed the pump) must be a installation related damage ?

here are some pics.. i hope you guys will find them usefull.


the complete fue lpump assembly



the two O-rings



they are of different sizes. The larger Dia O-ring is thinner and the small dia O-ring is thicker by 0.5mm





measuring the larger dia O-ring (thickness 3.0mm)



the smaller dia O-ring is thicker (3.5mm)

the pressure regulator and upper (circular) filter assembly



assembly opened up

the fuel pump itself






the pump's vanes can be seen here




pump Identification no. ?



The crescent shaped filter (this is the one which getrs blocked with dirt/grime from bad fuel)






The pump connection tabs


If you have forgotten to note down which wire goes where, don't sweat. The polarity is marked on the plastic. Red wire goes to "+" and the Black one to "-"

Great pic's, thanks for posting. makes me wonder if it would be possible to retrofit some sorta automotive style fuel filter to replace the "sock" filter. I will be traveling around South America for about a year and I know other people have had problems with dirty filters and failing fuel pumps. I have yet to take my pump apart but it would be nice if I could fit a generic/common car or truck style filter in there that I could easily find replacements for in the middle of Argentina and doesn't cost $100+.

Is this possible?

I know the pumps are pricey, but if i were to ride my 990 to S.A. I would
carry a spare pump and a set of filters.
When I rode my 950 down a few years ago I carried a fuel pump and H2O
pump rebuild kit.
I picked up my SE to ride back to Bolivia this fall. It's far simpler to work
on than the 990 with no ABS or EFI. But then again I've ridden my 990
over 25,000 miles in rough conditions with no issues and will leave in a
few weeks for two months of two up riding through Alaska and Canada,
on the 990.
Thanks for the tear down pics Mr.Vicks.
It would be helpful if someone could find a place to buy just the fuel pump
part of KTM's fuel pump assembly. It would save $ and be more compact to carry.
Twist it, MAX

Don't have a 990, but those pricey o-rings look a lot like some that came with a set of o-rings I bought at Harbor Freight for about $10, IIRC. It was an entire range of metric sizes and thicknesses. Paying $60 for those things is robbery.

Not sure its the same pump BUT

I googled MK5 Fuel pump and this is what came up.


http://cgi.ebay.co.uk/WALBRO-255-FU...temQQimsxZ20090423?IMSfp=TL090423139004r13097

maby its the same ?? its listed for 80 pounds uk.

http://www.nolimitmotorsport.com/walbro/

I have no idea if any of these pumps works or not for our bikes. Hope there is someone here with enough knowlidge to find out.

After doing the pump, i understand (pls correct me if i'm wrong) that the each of the inlet and outlet for the pump has a filter. The pump Inlet has the crescent (sock) filter and the outlet has the round paper element filter.

Its usually the crescent/sock filter which gets clogged and once this happens, the fuel flow slows down, thereby giving the characteristics experienced by many. During this clogging, if you shutdown the bike and start it again, the clogged filter probably gets freed up a li'l bit and then you get another few miles of riding before it gets clogged due to the dirt. The fuel pump itself looks pretty sturdy in design to me and i feel that all the 990 fuel pump problems (or atleast the majority of them) are due to failing filters, and not the pump mechanism itself.

If we can find a filter which will fit inside the tank, similar in size (filtering area) to the existing sock filter, and if we can manage to connect it to the fuel pump nozzle (by means of an adapter/pipe/reducer/connector etc) then we have a solution.

I'm trying to come up with a drawing to explain this .. shall get back in a while.

Excellent information Mr. Vicks.

Thanks for that and the time you took.

back home in Indiyeah, we have a saying that goes like "pour the water that you take from the pond, back into the pond"

i'm just doing that. i'm giving back to the pool from which i have learnt most of what i know today.

cheers guys

maybe this helps.

no it doesn't help

cos i ain't gonna spend 100s of dollars on that thing when i can think of a cheaper solution.

something like this. its still an idea, but let me see if i can make it materialise.

Fken A. i just go to the local bearing shop for those 1 dollar each and they are the ones that are viton, gets me all my steering head bearing with races complete, wheel bearings at a third or less of the oem, which is exactly where they get them from any way , the only time i had trouble was with a honda big end bearing, which is made special by a honda subsidiary i supose.

Thanks for that, did you perchance take a shot of the pump assembly with filter sock attached?

I'm still looking around for replacement O-rings for the fuel pump, so its still lying out side.

ask away for whatever pictures you need

will take pics and post up in a while.

picture of complete fuel pump assembly


with sock filter

the valve inside the fuel line disconnector which does not allow fuel to flow out once the disconnector is... well ..... disconnected !!!!




so dont go around disconnecting the fuel line, turning the engine over and get baffled cos no fuel flows out. It is NOT supposed to !!!

found them !!!

at an auto parts store

Do you think there is any possiblility to use paper from some other filter to excange the filter in the original KTM filter. I mean take the old dirty KTM filter apart and well, hmm, put paper from some stock cheap filter there instead ????

It would save a lot of money if possible.

Just thinking aloud , maby its not possible but would be nice to look into it. Have to take my filter out when back home and look into this.