HOW-TO: Convert 1989-2000 Petcock to non-vacuum operation

[coll0412]

How to convert your 1989-2000 vacuum petcock to work without vacuum with a simple flat head screwdriver.

1. First lets define how the petcock works before the mod. Putting the selector on "ON" allows fuel to flow from the "ON" inlet to the ENGINE when there is vacuum on the vacuum port. Putting the selector on "RES" allows fuel to flow from the "RES" inlet to the ENGINE when vacuum is in the vacuum port. Putting the petcock on "PRI" allows fuel to flow from the "RES" inlet to the ENGINE when there is NO VACUUM



2. Remove the bent metal sheet metal cover by lifting the two tabs and pulling the selector lever up and the bent sheet metal piece will come with. Put it down on the desk and do not disturb the orientation!



3. Rotate the blue selector valve 180° degrees from the factory position. I used a large flat head screw driver to rotate it 180°.


4. Take the selector valve and rotate the entire assembly, being careful not to disturb the sheet metal bracket to selector valve orientation. Rotate entire assembly 180° from how it came off and install back onto the petcock(DON"T FORGET THE SPRING").

5. Now lets check the operation.(NOTE: THERE IS NO VACUUM REQUIRED FOR THESE FLOWS, YOU CAN CHECK BY BLOWING ON LINES TO SEE FOR YOURSELF!)





Effectively the former "ON" inlet is now the "RES" inlet
The former "RES" inlet is now the "ON" inlet.
And the "PRI" position shuts the flow of entirely.

To correct for this you need to switch your RES and ON fuel lines at the tank(or just remember its backward!)

[ben2go]

Here's the original.
http://gstwins.com/gsboard/index.php?topic=19363.0



Here's a cheap replacement that doesn't require vacuum.
http://gstwins.com/gsboard/index.php?topic=36958.0

[Ronin]

Thank's Dude's !!!!  Thank's for the refresher...

[coll0412]

Yeah it only took me two years to write up....

[pbureau69]

okay question;

first we both agree suzuki created Putting the petcock on "PRI" allows fuel to flow from the "RES" inlet to the ENGINE when there is NO VACUUM

all I see this mod do is confuse RES and ON to work without vaccum, but we already have PRI for that function, or am I missing something in the functionality of the petcock.

I am not bashing your mod, Just trying to figure out the advantage (flow restriction on RES?)

I always run on PRI because always on the highway, if I did this mod, what advantage do I get on RES/ON over PRI (oem)?

[VSG]

The advantage is that that you'll be able to ride as if it's in PRIME, and still have the luxury of the Reserve amount.

So no fuel starvation on the hgihway, and you still have the reserve.

Buying the switch for the 04 Honda CR250FX does the same thing: gives you a non-vaccum on & reserve, and an "off".

[dgyver]

PRIME actually has a smaller orifice than RES and ON.

[Jerka]

So by doing this do you have to switch the gas off everytime you get off of the bike?  What if you are sitting in traffic for 2 or 3 minutes...do you have to worry about the carbs overflowing?  Do you leave the vacuum tube connected to the petcock or will it have to be capped? 

Sorry for all the questions...my diaphragm just bit the dust and I'm looking for a cheap, quick fix.

[ohgood]

So by doing this do you have to switch the gas off everytime you get off of the bike?  What if you are sitting in traffic for 2 or 3 minutes...do you have to worry about the carbs overflowing?  Do you leave the vacuum tube connected to the petcock or will it have to be capped? 

Sorry for all the questions...my diaphragm just bit the dust and I'm looking for a cheap, quick fix.

if your float needles are good, it won't hurt to leave it in the 'ON' or 'RESERVE' position overnight.

if they are damaged, you'll piss all that expensive gasoline on the deck.

[socialDK]

hey thanks for this tread. i keeped dying over the last few days did this quick mod and no more problems. thanks alot.