problem with emergency tank

[nick field]

ktm 620 egs-e adventure.......

i was wondering if any of you guys or gals have had problems with the emergency tank on the adventure.
i am finding that the bike cuts out leaving about a pint of fuel still in the tank. i can then restart using the thottle but will stall when this is released.
i have changed the tap due to a damaged o-ring and fuel hose to the correct length of 330mm.

any input will greatly be received, because my head is in bits searching for a solution.

[Ian]

This is probably obvious, but if I remember rightly doesn't the 620 Adventure have 3 fuel taps?

Secondly, is the hose which provides the vacuum for the fuel pump in good condition with no leaks and all connected OK?

Finally, is the fuel pump itself functioning correctly?

Cheers


[This message has been edited by Ian (edited 15 May 2004).]

[nick field]

thanks for your response and i apologise for the delay.
i have re-checked your suggestions and all seems too run fine until this last pint is required.

according to the good book (egs-e manual that came with the bike) the emergency tank is direct flow to the carb and is used when
- fuel pump failure (backup to the pump)
- prime the pump due too late switching from main-->rev.

i have tried every configuration with the present being clear hose too see the direction of travel of the fuel.

i have noticed that
-the emergency tank take off sits lower than the inlet of the carb and thus cuts out when these levels are the same. (atm pressure), this will explain the pint.
- the low pressure created in the venturi when acelerator/choke are open will syphon the fuel from the emergency tank but the bike will stall when released.
- i dont seem too get any pressure drop on idle too syphon the fuel from the emergency.

what i do find confusing are the layout of the fuel pipes which verified on the ktm world website have changed on later models.

i have made too many assumptions, of which i don't like doing. i do like hard facts, so any input pulling my points apart can only increase my knowledge on how it is and how it should work.

thanks again.

[neil.larsen]

Nick - just a couple of points to help you sort this out..
1) Venturi vacuum is highest when teh throttle is SHUT.
2) The float bowl in a carb normally breathes to atmosphere, so you will NOT be sucking fuel from the tank by means of the venturi vacuum.
3) however...the venturi vacuum does operate the fuel tap, where a vacuum tap is fitted.
4) Dont care what the book says, you need a pump of some sort to lift the fuel if it's below the level of the carb.

Sorry if you know all this already, but I can't help but wonder if your fuel pump is misbehaving.....
Cheers
neil

[SpiritualRider]

I have had many similar fuel problems with my EGS-E Adventure over the years.

I replaced the fuel pump at one point and that helped a lot, although I agree it doesn't have any bearing on the emergency tap, because, as you say, this bypasses the pump.

In my opinion this is quite simply poor design, as the fuel from the emergency tap is lower than the carb.

Whenever I got really stuck in the past I always managed to get going in the end by using the choke and then keeping the revs high while tentatively releasing the choke.

Once it gets going the carb will generally continue sucking the fuel out the tank; its getting it going in the first place that can be a bit tricky. If it feels like it's going to stall again, (e.g. at a junction) a little flick of the choke may help keep it going.

God knows what this must be doing for the life of the engine, but it’s always got me going in times of desperation.

One of these days I will write to KTM about what I see as this design fault. Also I will look into getting a better fuel pump (possibly electric?) before going away on a long journey again.

Regards,
Graham.