Hi all,

Trying to help a mate with an old but cherished Kawasaki ER-5 (500cc
twin).

Long short, as soon as you turn the fuel ('Prime') on it floods both
carbs.

Now, I'm very familiar with carbs and float jets etc so I've done most
of the usual stuff, and this is after the local bike shop has done the
same for him and suggested it needs a pair of good second hand carbs
(because the float valve seats may have worn oval?).

Now, it's only done 35k miles and the carbs seem in very good fettle
generally (throttle butterflies neat and tight, slides run freely etc)
and even with new float needles and the float heights set to stock
(17mm) they still leak (out though one of the jet holes and the carb
mouths). Even lowering the float heights to the max (19mm) doesn't
seem to help matters?

If you take the cabs off, hold them the right way up and blow into the
fuel line you can hear air passing though the jets and into the float
bowls. That's good.

Turn the carbs over and blow into the fuel hose and you would explode
your lungs before anything 'leaked'? That's also good?

Removing the float bowls and turning on the fuel sees the fuel pouring
out though the float jets. Lifting the floats with your fingers to
just the point where the (rubber) tip of the needle would touch the
seat and the flow stops? Push harder and the spring loaded plunger in
the back of the needle allows the float to travel further but the fuel
is already off at that point anyway?

So, the only thing that doesn't seem to work is the floats turning off
the flow of fuel when in the bowls as usual?

Now, the floats don't appear to have any leaks (and FWIW they both
weigh the same at 8 grams), you can't see any fuel in them because
they are translucent and don't *seem* to be in any way distorted where
they might touch the sides of the bowls etc?

So, when the bike ran last it generally performed well on the road
(and when it ran the few times today it sounded ok), the fault first
showed itself by a raised tickover and it has been suggested that
could have been fuel leaking into the crankcase (there was fuel in the
oil) and vapour being blown back up into the carbs via the breathers
and fuelling the engine that way (bypassing most of the carb functions
etc)?

So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Or what else could it be?

It *could* be intermittent because we tested it after cleaning and
calibrating by rigging up a temporary fuel tank and the carbs didn't
flood at all?

Cheers, T i m

T i m wrote:



Or what else could it be?

It *could* be intermittent because we tested it after cleaning and
calibrating by rigging up a temporary fuel tank and the carbs didn't
flood at all?

Cheers, T i m

is ther sufficient fuel flow out of the tank shutoff device
my triumph amal carb always starts to overflow when the in tank filter starts to block
if both cabs are doing the same thing then unlikely that they suddenly both have the some fault

-

On Tue, 7 Aug 2018 23:28:13 -0000 (UTC), Mark wrote:

T i m wrote:



Or what else could it be?

It *could* be intermittent because we tested it after cleaning and
calibrating by rigging up a temporary fuel tank and the carbs didn't
flood at all?

Cheers, T i m

is ther sufficient fuel flow out of the tank shutoff device

Good question. The fuel tap is 'remote' and vacuum operated so there
are 4 hoses. One the main tank outlet to the tap, one the reserve tank
outlet to the tap, the feed from the tap to the carb(s) and a vacuum
pipe to the inlet of one carb.

The tap has 3 positions, Prime (full on), On (main outlet enabled by
engine vacuum) Reserve (reserve outlet enable by engine vacuum). There
is no 'off' because without the engine running there is no vacuum on
the tap and so no fuel (except in the Prime position).

So, to answer your question I'd say 'yes' as it both seems to allow
the engine to flood pretty quickly (in any position) and filled a 5l
petrol can pretty quickly on Prime with the outlet going to the can.

my triumph amal carb always starts to overflow when the in tank filter starts to block

Oooerr?

if both cabs are doing the same thing then unlikely that they suddenly both have the some fault

Agreed ... and why I was asking here. ;-)

Googling around on the ER-5 bike it seems the symptom of sitting at
3000 rpm on tickover and flooding are both 'known issues', some of
which are down to the fuel tap not turning off *and* the float jets
not turning off (even with the bike parked and idle etc).

Apparently the 3000 rpm tickover issue can be related to a leaking
throttle slide diaphragm but I'm less worried about that whilst we
have the flooding issue whilst the engine is turned off.


Cheers, T i m

On Tuesday, 7 August 2018 23:01:36 UTC+1, T i m wrote:
Hi all,

Trying to help a mate with an old but cherished Kawasaki ER-5 (500cc
twin).

Long short, as soon as you turn the fuel ('Prime') on it floods both
carbs.

Now, I'm very familiar with carbs and float jets etc so I've done most
of the usual stuff, and this is after the local bike shop has done the
same for him and suggested it needs a pair of good second hand carbs
(because the float valve seats may have worn oval?).

Now, it's only done 35k miles and the carbs seem in very good fettle
generally (throttle butterflies neat and tight, slides run freely etc)
and even with new float needles and the float heights set to stock
(17mm) they still leak (out though one of the jet holes and the carb
mouths). Even lowering the float heights to the max (19mm) doesn't
seem to help matters?

If you take the cabs off, hold them the right way up and blow into the
fuel line you can hear air passing though the jets and into the float
bowls. That's good.

Turn the carbs over and blow into the fuel hose and you would explode
your lungs before anything 'leaked'? That's also good?

Removing the float bowls and turning on the fuel sees the fuel pouring
out though the float jets. Lifting the floats with your fingers to
just the point where the (rubber) tip of the needle would touch the
seat and the flow stops? Push harder and the spring loaded plunger in
the back of the needle allows the float to travel further but the fuel
is already off at that point anyway?

So, the only thing that doesn't seem to work is the floats turning off
the flow of fuel when in the bowls as usual?

Now, the floats don't appear to have any leaks (and FWIW they both
weigh the same at 8 grams), you can't see any fuel in them because
they are translucent and don't *seem* to be in any way distorted where
they might touch the sides of the bowls etc?

So, when the bike ran last it generally performed well on the road
(and when it ran the few times today it sounded ok), the fault first
showed itself by a raised tickover and it has been suggested that
could have been fuel leaking into the crankcase (there was fuel in the
oil) and vapour being blown back up into the carbs via the breathers
and fuelling the engine that way (bypassing most of the carb functions
etc)?

So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Or what else could it be?

It *could* be intermittent because we tested it after cleaning and
calibrating by rigging up a temporary fuel tank and the carbs didn't
flood at all?

Cheers, T i m

Crap in the fuel tank/damaged/disintegrating/missing fuel filters can lodge in the float valve seats so causing leakage.
Fuel filter usually attached to fuel shutoff tap inside tank..


When I was a teenager we used to grind float valves in if they leaked.

On Wed, 8 Aug 2018 00:09:33 -0700 (PDT), harry
wrote:

snip

Crap in the fuel tank

How often should we do that? boom tish ;-)

/damaged/disintegrating/missing fuel filters can lodge in the float valve seats so causing leakage.

True.

Fuel filter usually attached to fuel shutoff tap inside tank.

Except this setup has a remote tap (so no tap fitted to the tank
itself) and unless there is a filter inside the tap, there isn't one
on there. We have spoken of fitting one but they can cause issues
themselves (I fitted two on my BMW motorbike and had to remove them on
the first trip).


When I was a teenager we used to grind float valves in if they leaked.

These are rubber tipped so again, not possible in this instance.
However, they are brand new (carb service kit).

It's very frustrating.

A float valve is the most basic of mechanical systems and on the
bench, everything about these look perfect.

Further, with the basic 'blow into the fuel line and test the float
valves the right way up and upside down (so the valves only being
closed by the weight of the floats and jets) seem to demonstrate the
things as working perfectly? Operating the floats manually whilst sat
on the bike (with the float bowls off) also demonstrates they are
working perfectly?

So it's looking like the (hollow plastic) floats aren't working
properly when they are expected to 'float' (in petrol) but they don't
appear to be punctured or cracked or have taken on any fuel (and at 8g
weigh exactly the same).

Cheers, T i m

T i m wrote:
Hi all,

Trying to help a mate with an old but cherished Kawasaki ER-5 (500cc
twin).

Long short, as soon as you turn the fuel ('Prime') on it floods both
carbs.

Now, I'm very familiar with carbs and float jets etc so I've done most
of the usual stuff, and this is after the local bike shop has done the
same for him and suggested it needs a pair of good second hand carbs
(because the float valve seats may have worn oval?).

Now, it's only done 35k miles and the carbs seem in very good fettle
generally (throttle butterflies neat and tight, slides run freely etc)
and even with new float needles and the float heights set to stock
(17mm) they still leak (out though one of the jet holes and the carb
mouths). Even lowering the float heights to the max (19mm) doesn't
seem to help matters?


Wouldn't you need to raise the float heights?

I had an Amal concentric on me old Tiger Cub, and that had a punctured
float, but you've already checked that. I'd only add that the puncture
was tiny, and you couldn't hear the petrol splashing about. The floats
weren't clear like yours, though. In those days, there was a metal tab
that you needed to bend up to make the adjustment.

Maybe the floats have 'shrunk' with age and become denser? Everything
else (blowing in the pipe while they're upside down) makes it sound like
they would be fine as long as the float lifted properly.

If you take the cabs off, hold them the right way up and blow into the
fuel line you can hear air passing though the jets and into the float
bowls. That's good.

Turn the carbs over and blow into the fuel hose and you would explode
your lungs before anything 'leaked'? That's also good?

Removing the float bowls and turning on the fuel sees the fuel pouring
out though the float jets. Lifting the floats with your fingers to
just the point where the (rubber) tip of the needle would touch the
seat and the flow stops? Push harder and the spring loaded plunger in
the back of the needle allows the float to travel further but the fuel
is already off at that point anyway?

So, the only thing that doesn't seem to work is the floats turning off
the flow of fuel when in the bowls as usual?

Now, the floats don't appear to have any leaks (and FWIW they both
weigh the same at 8 grams), you can't see any fuel in them because
they are translucent and don't *seem* to be in any way distorted where
they might touch the sides of the bowls etc?

So, when the bike ran last it generally performed well on the road
(and when it ran the few times today it sounded ok), the fault first
showed itself by a raised tickover and it has been suggested that
could have been fuel leaking into the crankcase (there was fuel in the
oil) and vapour being blown back up into the carbs via the breathers
and fuelling the engine that way (bypassing most of the carb functions
etc)?

So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Or what else could it be?

It *could* be intermittent because we tested it after cleaning and
calibrating by rigging up a temporary fuel tank and the carbs didn't
flood at all?

Cheers, T i m

On Wed, 8 Aug 2018 10:24:40 +0100, "Dan S. MacAbre"
wrote:

T i m wrote:
Hi all,

Trying to help a mate with an old but cherished Kawasaki ER-5 (500cc
twin).

Long short, as soon as you turn the fuel ('Prime') on it floods both
carbs.

Now, I'm very familiar with carbs and float jets etc so I've done most
of the usual stuff, and this is after the local bike shop has done the
same for him and suggested it needs a pair of good second hand carbs
(because the float valve seats may have worn oval?).

Now, it's only done 35k miles and the carbs seem in very good fettle
generally (throttle butterflies neat and tight, slides run freely etc)
and even with new float needles and the float heights set to stock
(17mm) they still leak (out though one of the jet holes and the carb
mouths). Even lowering the float heights to the max (19mm) doesn't
seem to help matters?


Wouldn't you need to raise the float heights?

Yes / no, I think this is just a terminology thing Dan.

The spec says 17 +-2mm so 15-19mm. We initially set them to 17mm and
that is really the *distance* (not 'height' as such) between the
bottom of the float (when the carb is the right way up) and the body
of the carb, when the float is dangling such as to *just* close the
valve. So making that a bigger number will cause a lower fuel level (I
believe). ;-)

I had an Amal concentric on me old Tiger Cub, and that had a punctured
float, but you've already checked that.

The best we can Dan. Luckily the floats are hollow plastic,
translucent and made of two 'sides', and neither side on neither
floats are leaking that we can tell?

I'd only add that the puncture
was tiny, and you couldn't hear the petrol splashing about.

Yes, I have experienced that in the past, confirm we tested for that
(sploshage) and couldn't sense any at all.

The floats
weren't clear like yours, though. In those days, there was a metal tab
that you needed to bend up to make the adjustment.

Same now days. ;-)

Maybe the floats have 'shrunk' with age and become denser?

I'm at the point where I'd consider anything possible!

Everything
else (blowing in the pipe while they're upside down) makes it sound like
they would be fine as long as the float lifted properly.

Precisely. The only issue I can think of with that test is that the
weight of the (very light) floats when upside down in air may offer a
grater closing force to the jets than the floats floating in petrol
(but really)?

snip

Apparently these Kawasaki ER-5's (and other makes and models no doubt)
suffer with issues of the automatic (intake vacuum driven) fuel taps
not closing fully / intermittently but I've only ever turned the fuel
taps of my motorcycles off when I've finished using them that day, not
because not doing so will see them flood? ;-(

Ok, I think the carbs on my old 'Airhead' BMW's have been know to
flood but all that does is soaks your boot, not flood the engine /
crankcase / airbox and a quick clean (and the float bowl clips on,
making that a roadside job). ;-)

Cheers, T i m

In article ,
T i m wrote:
So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Dunno these carbs, but with SUs you'd tend to replace the valve and seat
complete - it just screwed in.

Does the valve and seat look OK under a magnifying glass? If not, and the
seat is part of the carb body, I'd be inclined to lap the valve to it.

Other thing is not enough lift from the float, or it sticking. But you
seem to have covered this. I assume you can't just by new ones?

--
*If you remember the '60s, you weren't really there

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 08 Aug 2018 13:49:21 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Dunno these carbs, but with SUs you'd tend to replace the valve and seat
complete - it just screwed in.

Yeah, same on many bikes Dave, just not this one.

Does the valve and seat look OK under a magnifying glass?

I've not looked by daughter has (with her good eyes) but I should be
able to get in there with an endoscope.

If not, and the
seat is part of the carb body, I'd be inclined to lap the valve to it.

Except, these bike valves are often rubber tipped and so you couldn't
really use the valve itself to do any lapping.

Other thing is not enough lift from the float, or it sticking. But you
seem to have covered this.

Well, sort of. I am wondering if the float upside down in air is the
same (jet-sealing) effect as the right way up in petrol (buoyancy V
mass etc).

I assume you can't just by new ones?

No, you probably can but I'd hate to think how much. The throttle
slide diaphragms on this model are ~£100 each. ;-(

One thing I have learned since posting is that you can put a small
clear hose on the bowl drain nipple and run it up beside the carb.
Then you crack the drain screw(s) open, apply fuel then you can see
what the fuel level is in the carb bowl(s). ;-)

And that's fine of course, *if* it doesn't flood straight away! ;-(

Cheers, T i m

In article ,
T i m wrote:
If not, and the
seat is part of the carb body, I'd be inclined to lap the valve to it.

Except, these bike valves are often rubber tipped and so you couldn't
really use the valve itself to do any lapping.

Ah - of course. Think those arrived on later SUs too. I'd guess the rubber
might wear or perish etc? No chance of buying new? Checked Ebay etc for
pattern parts?

--
*I have a degree in liberal arts -- do you want fries with that

Dave Plowman London SW
To e-mail, change noise into sound.

On Thu, 09 Aug 2018 10:46:02 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
If not, and the
seat is part of the carb body, I'd be inclined to lap the valve to it.

Except, these bike valves are often rubber tipped and so you couldn't
really use the valve itself to do any lapping.

Ah - of course. Think those arrived on later SUs too. I'd guess the rubber
might wear or perish etc?

I think the classic failure mode for them is the develop a ridge where
they sit on the hole in the seat.

No chance of buying new?

New already fitted. ;-(

Cheers, T i m