hose from petcock to Carb 4?...... Should there be one?

[marcusdweaver]

Good evening all,

This is my first post and i greatly appreciate this forum and hope you guys can help.

I got my first kat on monday. It is a 91, 600 with 24k miles and she wasant in the best shape. I cleaned the carbs in accordance with Carbs 101 (great tutorial), drained and cleaned the gas tank, and replaced the air filter. I got the carbs all put back together last night when i realized i had no gas to start her up. so tonight i will see if i did a good job puting everything back together. (fingers crossed) If i have time i will also change the oil and attempt to sync the carbs. She ran when i got her "barely" and would idle for about 45 seconds at 800 rpm before she would die. so hopefuly this cleaning and sync will help but I noticed some posts that mention a line coming from the #4 carb to the petcock. I do not have one. Just the fuel line. the othr porton the petcock has a rubber cap over it. Am i supposed tohave one? where on the carb does it attach?



Also my airbox drain has no line coming out of it. it is vented to the atmosphere. is it suposed to be?

Thanks

[Stumpy]

urgh - messy!

You'll be leaking vacuum as you don't have a capped airbox line. Get some line, attach it to the barb and run it out down near the footpeg and the tank overflow line. Cap it off with a bung and a pushclip, or a bend it back and tie-wrap it if you have to.

#4 carb line to petcock is vacuum to open the diaphragm and let fuel flow. If it's not there, it's entirelly possible you have a petcock that is purely gravity fed and so does not require it.

Pics will help!

[Kreylyn]

The vauge description is leading me to believe that you have a modified bike using mixed parts.

The 91 OEM used dual output fuel lines from the petcock to the carbs (2 fuel lines) and a vacuum line from the side of #4 carb to the petcock back side for vacuum operation of the petcock.

Running 1 line split to 2 into the carbs doesn't work as well if that is what they did.

Is there a fuel filter on the fuel line as well?

Take some pics... of the carbs and the rest of the setup. Closer up pics so we can actually see details. I don't need to see a 10 foot away pic of the bike.

Krey

[marcusdweaver]

ok, so it looks like you are correct Kreylyn. i have put some close up pictures in my garage of my petcock and carbs. I have MIKUNI carbs..... anyone know how to sync them?
As far as the fuel lines that are attached there is a single line leading from the petcock to the carbs. it splits in the middle and feeds the ports between crabs 1&2 and 3&4. the pictures in my garage show the underside view of the fuel tank with all hoses that i have connected. it may be an aftermarket petcock because the picture does not seem to match the one in the repair manual. If anyone has any advice on this setup please help me to make sure everything is hooked up right. Thanks

[Stumpy]

WTF?

need pics of this!

OK - seen the pics You have some bulging in boot #3 - I'd replace that. Still no good pics of the petcock though - I can't even see how many lines it takes from those photos. Unless I'm being an idiot or something.

[marcusdweaver]

pics are in my garage

[Kreylyn]

So.... you got yourself a project there. And the project isn't that the bike is old, it's that the Previous Owner (PO) was just awesome! /sarcasm

Just the quick over view of the bike with the GSXR rear end "stuck" on there gave me pause. Your probably going to find all kinds of issues coming up.

So I have to ask... what are you wanting out of the bike? Just Get it running, fix it up right but keep the POs line of though, or go back original?

As for issues I could see in the pic...

Wrong clamps on the air box boots.

Carbs were not fully seated in the engine boots.

Vacuum port on #4 carb is capped off instead of having the right vacuum line.

Missing vent lines on the top of the carbs.

(couldn't see, but by your description... )

Wrong petcock or modified petcock that isn't working right.

Wrong fuel lines setup.


If it was me... I would remove all of the plastics and start at the base of the bike. Look for missing bolts/nuts. Make sure what is there are all tight.

Clean it well (wash it all) and then start with a valve adjustment. Then tear down the carbs and do a full cleaning. Replace/fix the petcock. Make sure the rubber boots on both sides of the carbs are in good condition, including the Orings on the back side of the engine boots. Replace all the lines correctly. Clean and reseal the air box boots to the air box. Start the bike and sync the carbs.

Then you will have a base to work from.

Krey

[marcusdweaver]

[Stumpy]

Yup - thats a gravity feed. You are in for some fun getting this thing working

[marcusdweaver]

Ok so there is a few pictures of the underside of my fuel tank. Will someone please tell me if i need a new petcock in order for the correct fuel line system to be in place? also when i filled the tank i noticed that fuel flows from the petcock in all 3 positions freely (some more than others). if this is the correct petcock would i need a rebuild kit?

as far as what i want out of this bike...... i want to be able to ride....and i want her to run smooth and be reliable. if i can achieve that with the curent setup then i am ok i just want to be sure that as far as the engine goes. she is where she needs to be to run like new.

This is my first bike ever and i am a big lover of projects so these setbacks do not bother me. i just want to be sure that the setup on it is correct so i do not cause more harm then good.

ok so it is gravity fed. does that mean i need a new petcock assembly?

[Stumpy]

I'd get an OEM replacement. I'm not familiar with the pre 98 bikes, not worked on one or ridden one, so I can't comment on their fuel systems in detail. All I can really do is have a beer for you and hope you get it running soon

[marcusdweaver]

Can someone tell me if this choke is on or off? i am not sure if it is hooked up backwards?

[IMG][/IMG]

Yes if it wasnt labor day i would go buy a new OEM one and some fuel/vac lines now but all the stores are closed. I'm dying to get it running........ wife's not happy lol

[Kreylyn]

Choke is on in the pic. The plungers go in to be closed (move the rail left as oriented in the pic...)

Your petcock is not for the right year model bike. It's either an 88-89, or 98-06 petcock (or non OEM made after those models). I would suggest replacement with one from 90-97 600, or 89-97 750 that has dual fuel output.

Your assessment of the petcock you have not working correctly is also on target. A rebuild though may not fix the issue, as it is possible the problem is the assembly or bent prime spring internally. I would open it up and inspect to verify before purchase of a rebuild kit (contingent on if you are going to try and use or fix that one anyways.)

Krey

[marcusdweaver]

OK I will get an OEM petcock and hook it up the way it is supposed to be.

currently the bike runs good but only if the choke is fully on. The choke switch says it is off but apparently the Carb pic I posted earlier in this thread state otherwise. I will have to swap the cable from the choke lever to orient it correctly.

i am guessing that the bike will only run with the choke fully on because I have a gravity fed fuel system that is flooding the bowls? Hopefully the proper fuel line setup will fix it.

[Kreylyn]

OK I will get an OEM petcock and hook it up the way it is supposed to be.

currently the bike runs good but only if the choke is fully on. The choke switch says it is off but apparently the Carb pic I posted earlier in this thread state otherwise. I will have to swap the cable from the choke lever to orient it correctly.

i am guessing that the bike will only run with the choke fully on because I have a gravity fed fuel system that is flooding the bowls? Hopefully the proper fuel line setup will fix it.

I think there might be some confusion.

"Choke" for these bikes is just a generic term, and isn't really a choke. A real choke is a plate that blocks or chokes off air flow. That's not what happens on your bike. On these bikes, "choke" is a fuel enrichement system. When you pull the cable, 4 plungers slide open on each carb. That plunger allows the vacuum flowing through the carbs to pull fuel from the bottom of the bowls and pump it directly into the intake in addition to the fuel already flowing from the jets.

Cold engines need a rich enviroment to start. Less air or more fuel = rich. So... it just uses a different method to accomplish that rich fuel mix for starting.

If your bike won't run with out choke on... it's most likely that your carbs need serious cleaning because the pilot fuel system inside the carbs is not working right.

As a quick review... Choke adds fuel. Throttle adds Air. Choke to richen it. Throttle to lean it out.

Krey