GPX 600

 Hi,
Anyone know the pilot air screw settings (turns out) for a 1989 gpx600.
Carbs have been stripped and cleaned and new O rings fitted to the pilot air
screws,set them 2 turns out but is still running weak,turned the outer ones
out a bit more and this improved things but i need to take the carbs off
again to set the inner ones Any help appreciated.
Ken

 wrote:

I don't need to remove the carbs from my bikes to adjust the idle
mixture screws because I have a very short slot screwdriver tip that
came with a set of tips that go in a 1/4 inch socket.

The tips are only about an inch long...

It's hard to say exactly what the idle mixture screw settings should
be without knowing what size the idle jets (pilot jets) are.

The ordinary range of idle screw settings can be as little as 1/8th of
a turn out from lightly seated if you have #40 to #42 idle jets and as
many as 3-1/2 turns open when you have #30 or #32.5 idle jets on a
larger engine.

Generally there is no effect to turning the screws out more than 3-1/2
turns because the idle mixture is too rich.

You can usually tell that the idle mixture is too rich when you start
a cold engine using full choke and the RPM races up too fast.

Also, you'll know that the idle mixture is too rich when the RPM hangs
up too high
after the engine is hot.

You can tell the idle mixture is too lean when you roll off the
throttle and you hear a piffle-piffle-snap sound out the exhaust as
you decelerate.

If the idle mixture is too lean, you won't get the throttle response
you want as you accelerate from closed throttle.

If the idle mixture is too rich, you might hear a fart-BANG sound out
the exhaust when you roll the throttle off.

 
wrote:

I don't need to remove the carbs from my bikes to adjust the idle
mixture screws because I have a very short slot screwdriver tip that
came with a set of tips that go in a 1/4 inch socket.

The tips are only about an inch long...

It's hard to say exactly what the idle mixture screw settings should
be without knowing what size the idle jets (pilot jets) are.

The ordinary range of idle screw settings can be as little as 1/8th of
a turn out from lightly seated if you have #40 to #42 idle jets and as
many as 3-1/2 turns open when you have #30 or #32.5 idle jets on a
larger engine.

Generally there is no effect to turning the screws out more than 3-1/2
turns because the idle mixture is too rich.

You can usually tell that the idle mixture is too rich when you start
a cold engine using full choke and the RPM races up too fast.

Also, you'll know that the idle mixture is too rich when the RPM hangs
up too high
after the engine is hot.

You can tell the idle mixture is too lean when you roll off the
throttle and you hear a piffle-piffle-snap sound out the exhaust as
you decelerate.

If the idle mixture is too lean, you won't get the throttle response
you want as you accelerate from closed throttle.

If the idle mixture is too rich, you might hear a fart-BANG sound out
the exhaust when you roll the throttle off.

Thanks for the response m8
I dont know the size of the jets i assume there standard,problem is throttle
response with the jets tuned out 1-2 turns it wont take the throttle at all,
as i said i turned the outer ones out a bit more and this improved things.
Ive thoroughly cleaned out the carbs (twice) and made sure the rubber
connections to the air box are ok.I`ll try using a short bit as you suggest
giving them maybe 3 turns

 

How thoroughly? Ultrasound? Compressed air?


--
BMW K1100LT  Ducati 750SS  Honda CB400F  Triumph Street Triple
Suzuki TS250ER  Coo, down to just five bikes!
If you don't know what you're doing, don't do it. And RTFM.
chateau dot murray at idnet dot com

 wrote:


If the engine dies when you twist the throttle grip, the idle passages
and ports are all plugged up with gum and varnish. You can use a clear
carburetor cleaner that
contains acetone and toluene to quickly clean out the passages.

One way to get the carb cleaner into the carbs is to disconnect the
rubber fuel hose and spray it into the float bowls using the red
plastic straw that comes with every can of aerosol carb cleaner.

Another way is to add 4 or 5 ounces of carb cleaner to a full tank of
gasoline and ride until the engine starts running better, but the
engine has to be running well enough to allow you to ride safely.

A third way is to spray carb cleaner into the carbs through the pilot
air jet if it's in the intake bell of the carb. If it is there, it's
the smaller hole. If the pilot air jet isn't in the intake, it's
underneath the rubber diaphragm that raises and lowers the vacuum
slide.