Air cleaner is not at fault, problem is still active when air cleaner
is disconnected. I was told to try two tests. 1) disconnect fuel line
and use a seperate container directly to the fuel line, 2) also check
to see if diaphram needle is coming completly up on acceleration.

I will let you know what happens with tests.

--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "Clive"
< This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

If you start the bike, then take off the air filter does it get

better

QUOTE:
or worse?
If worse, I would check the manifold to make sure there are no leaks
or cracks. Could also be you have a weak spark so double check all
spark plug cable connections.
If it gets better, you could have a blocked air filter (dust or oil).
Since the issue seems to be above idle, it could also be your main

jet

QUOTE:
is still blocked or the float level is too low (latter would me more
unusual since floats tend to go other way over time).
Clive.

Forget the first test but the second has merit. That\'s why I asked
you to check the rolling diaphragm. You see the slide is not
mechanically actuated but is pulled up by partial vacuum caused by
air flow thru the carb throat. A tear or hole in the diaphragm will
allow it to move only so far until it begins to leak, loose vacuum,
and then drop. Then it starts all over again in a surging or pulsing
sequence.
--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "David
Sallee" < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

Air cleaner is not at fault, problem is still active when air

cleaner

QUOTE:
is disconnected. I was told to try two tests. 1) disconnect fuel

line

QUOTE:
and use a seperate container directly to the fuel line, 2) also

check

QUOTE:
to see if diaphram needle is coming completly up on acceleration.

I will let you know what happens with tests.

--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "Clive"
<clive@> wrote:

QUOTE:

If you start the bike, then take off the air filter does it get

better

QUOTE:
or worse?
If worse, I would check the manifold to make sure there are no

leaks

QUOTE:

QUOTE:
or cracks. Could also be you have a weak spark so double check

all

QUOTE:

QUOTE:
spark plug cable connections.
If it gets better, you could have a blocked air filter (dust or

oil).

QUOTE:

QUOTE:
Since the issue seems to be above idle, it could also be your

main

QUOTE:
jet

QUOTE:
is still blocked or the float level is too low (latter would me

more

QUOTE:

QUOTE:
unusual since floats tend to go other way over time).
Clive.

OK in trying to identify Walbro carb parts. Looking at the carb
oposite side from the enricher ( choke ) , what it behind the dime
size cap ( this will be on trottle cable side of carb). My mechanic
is curious on what purpose this item is?


--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "tomcas1234& quot; < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

Forget the first test but the second has merit. That\'s why I asked
you to check the rolling diaphragm. You see the slide is not
mechanically actuated but is pulled up by partial vacuum caused by
air flow thru the carb throat. A tear or hole in the diaphragm

will

QUOTE:
allow it to move only so far until it begins to leak, loose

vacuum,

QUOTE:
and then drop. Then it starts all over again in a surging or

pulsing

QUOTE:
sequence.
--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "David
Sallee" <davsal@> wrote:

QUOTE:

Air cleaner is not at fault, problem is still active when air

cleaner

QUOTE:
is disconnected. I was told to try two tests. 1) disconnect fuel

line

QUOTE:
and use a seperate container directly to the fuel line, 2) also

check

QUOTE:
to see if diaphram needle is coming completly up on

acceleration.

QUOTE:

QUOTE:

I will let you know what happens with tests.

--- In Strada-Vento-QJ-UM-

ChineseScooters@yaho ogroups.com, "Clive"

QUOTE:

QUOTE:
<clive@> wrote:

QUOTE:

If you start the bike, then take off the air filter does it

get

QUOTE:

QUOTE:
better

QUOTE:
or worse?
If worse, I would check the manifold to make sure there are no

leaks

QUOTE:

QUOTE:
or cracks. Could also be you have a weak spark so double

check

QUOTE:
all

QUOTE:

QUOTE:
spark plug cable connections.
If it gets better, you could have a blocked air filter (dust

or

QUOTE:
oil).

QUOTE:

QUOTE:
Since the issue seems to be above idle, it could also be your

main

QUOTE:
jet

QUOTE:
is still blocked or the float level is too low (latter would

me

QUOTE:
more

QUOTE:

QUOTE:
unusual since floats tend to go other way over time).
Clive.

I think that\'s the air cutoff valve. It\'s purpose is to richen the
fuel mixture on deceleration to prevent backfire.

--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "David
Sallee" < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

OK in trying to identify Walbro carb parts. Looking at the carb
oposite side from the enricher ( choke ) , what it behind the dime
size cap ( this will be on trottle cable side of carb). My mechanic
is curious on what purpose this item is?


--- In Strada-Vento-QJ-UM-
ChineseScooters@yaho ogroups.com, "tomcas1234& quot; <tomcas@> wrote:

QUOTE:

Forget the first test but the second has merit. That\'s why I

asked

QUOTE:

QUOTE:
you to check the rolling diaphragm. You see the slide is not
mechanically actuated but is pulled up by partial vacuum caused

by

QUOTE:

QUOTE:
air flow thru the carb throat. A tear or hole in the diaphragm

will

QUOTE:
allow it to move only so far until it begins to leak, loose

vacuum,

QUOTE:
and then drop. Then it starts all over again in a surging or

pulsing

QUOTE:
sequence.
--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "David
Sallee" <davsal@> wrote:

QUOTE:

Air cleaner is not at fault, problem is still active when air

cleaner

QUOTE:
is disconnected. I was told to try two tests. 1) disconnect

fuel

QUOTE:

QUOTE:
line

QUOTE:
and use a seperate container directly to the fuel line, 2) also

check

QUOTE:
to see if diaphram needle is coming completly up on

acceleration.

QUOTE:

QUOTE:

I will let you know what happens with tests.

--- In Strada-Vento-QJ-UM-

ChineseScooters@yaho ogroups.com, "Clive"

QUOTE:

QUOTE:
<clive@> wrote:

QUOTE:

If you start the bike, then take off the air filter does it

get

QUOTE:

QUOTE:
better

QUOTE:
or worse?
If worse, I would check the manifold to make sure there are

no

QUOTE:

QUOTE:
leaks

QUOTE:

QUOTE:
or cracks. Could also be you have a weak spark so double

check

QUOTE:
all

QUOTE:

QUOTE:
spark plug cable connections.
If it gets better, you could have a blocked air filter (dust

or

QUOTE:
oil).

QUOTE:

QUOTE:
Since the issue seems to be above idle, it could also be your

main

QUOTE:
jet

QUOTE:
is still blocked or the float level is too low (latter would

me

QUOTE:
more

QUOTE:

QUOTE:
unusual since floats tend to go other way over time).
Clive.

Yes he is unfamiliar with these scooters, he makes his living working
on american made automobiles. Kind of taking him out of his element
helping me out on my chinese scooters. Not to mention he rides a 06\'
Harley Davidson, that makes it even more embarrasing asking for help.
He has been real nice with everything. And no I am not talking about
the little pump on the side of the carb, he figured that one out, this
is just above this on the same side of the carb, has some sort of
channel going upward to the diaphram area.

--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "Clive"
< This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

That is an accelerator pump. It uses a small diaphragm to squirt

more

QUOTE:
gas into the carb when the throttle is opened quickly to prevent
hesitation on fast acceleration. If its bad you would get the
hesitation, but unlikely to have the problems you mentioned. Sounds
like your mechanic is not familiar with bike carbs (esp CV types).
Clive.

The acelerator pump is easy to ID because it has a bellows dust deal,
an extension rod, and is actuated by a lever. What he describes as a
diaphragm under a dime sized cap does not fit this description but
describes the air cut off valve.
--- In Strada-Vento-QJ-UM- ChineseScooters@yaho ogroups.com, "Clive"
< This e-mail address is being protected from spam bots, you need JavaScript enabled to view it > wrote:

QUOTE:

That is an accelerator pump. It uses a small diaphragm to squirt more
gas into the carb when the throttle is opened quickly to prevent
hesitation on fast acceleration. If its bad you would get the
hesitation, but unlikely to have the problems you mentioned. Sounds
like your mechanic is not familiar with bike carbs (esp CV types).
Clive.