12 replies to this topic

[Bjørge]

I've tried to adjust fuel levels, after installing el fuel pump. Fuel levels were way too high, in the range of maybe 5mm. Bent tangs to get levels within specs, but they are now barely open when float is in min. position. Strange?

At first (new float valves, vacuum pump) levels were too low, caused by a stiffer spring, methinks.

Also, what is the smallest off-adjustment level you have experienced to affect running, or the other way - largest off-adjustment that did not affect running?

[Studley Ramrod]

Shouldn't really matter if they only look to be barely open so long as they're filling the carbs.  I'd expect them to be closer due to leccy pump in place of vac wan.

Difficult to know really, unless you've actually run the bike at many different fuel level settings and recorded them all.  Given that there's only 1mm to play with between min and max fuel level, I would imagine it's fairly critical.  Maybe a couple of mm ?

[Bjørge]

Yeah, seems probable. This implies that a worn vacuum pump would also cause a slightly lowered fuel level....

Adjusting the fuel level accurately is not easy, especially when the 1mm range is to be hit. The capillary effect makes it all but a straight line....
I'll give it a try tomorrow!

[Bjørge]

Tested today. Someting's horribly wrong. Lack of power when on higher rpms and anything beyond half throttle. Stumbles.
I start wondering if it's the measuring procedure...what's the actual fuel level in bowl supposed to be when running?
One question I ask is what's happening when you open the drain screw to let fuel flow into the the clear tube to measure? Is there still pressure to fill bowl, or is internal fuel level sinking? If the latter is the case, then length and inner diameter of tube will be crucial...

[Studley Ramrod]

Fuel level when running should be the same.  Should be enough pressure to keep fuel bowl full, assuming your fuel supply is higher than the carbs.  Worth making sure the drain screws are opened a good few turns or you might get a false reading.

[Bjørge]

You're probably right, it would fill up anyways....
Afraid I just have to try without measuring. But it's such a hassle!

[Bjørge]

Bit the bullet, and ordered a 2nd hand FZR fuel pump, starting all over....

[Bjørge]

Well, finally got to pick up this work after selling the 9er😐. Carbs on bench, reset level to ~0 by straightening tangs. Still on gravity feed. Todays project is hooking up the fzr pump to see effect on fuel level before trying to hit the sweet spot.

Any guesses out there? Will leccy pamp affect fuel levels?

...should mention I've installed new OEM valves...

Edited by Bjørge, 01 May 2020 - 09:15 am.

[drewpy]

Well, finally got to pick up this work after selling the 9er. Carbs on bench, reset level to ~0 by straightening tangs. Still on gravity feed. Todays project is hooking up the fzr pump to see effect on fuel level before trying to hit the sweet spot.

Any guesses out there? Will leccy pamp affect fuel levels?

...should mention I've installed new OEM valves...

when I had a fuel pump , i lowered the float by 1mm after installing new float needles 

[Bjørge]

when I had a fuel pump , i lowered the float by 1mm after installing new float needles 

I just tried it, and the pump doesn't seem to affect level. That is, I found out auxilary fuel tank affected fuel level below a certain height. After raising it, there was no rise in level when I switched pump on.

Very happy with that, now I just need to get level up some 5 and 7mm.

Btw, this is a ~1990 fzr600 pump, and it is very much less noisy than the chinese crap one I tried earlier😎
Also, fuel lines seem to fit, being 8mm.

[Bjørge]

Didn't think of what angle carburetter sits on bike...😱

Starting over 😎

[drewpy]

Didn't think of what angle carburetter sits on bike...

Starting over

that helps 

[Bjørge]

Finally got the levels right, and it seemed reasonable as tangs were about straight.
Looking forward to install tomorrow and maybe hear the old cow running again 😎