yzf600 tank question

[mxryder21]

I'm still doing mock-up and right now I'm on the tank. I know that the red fuel hose connects to the brass colored nipple on the petcock but there is a smaller nipple and I have no idea what it's for. Do I just plug it?

[Ickis]

Simple answer is no. First, depending on the year of tank, I recall that the early versions of the YZF600 tanks had an internal fuel pump. So from there you would route the fuel line Petcock > Fuel Filter > Carbs. Otherwise, if it's one of the later models, it'd be Petcock > Fuel Filter > Fuel Pump > Carbs. That tank looks like one of the earlier models with the internal fuel pump. But this is just off the top of my head and I may be wrong. BTW, is that two outlets on the petcock that I see?

[mxryder21]

BTW, is that two outlets on the petcock that I see?

That's what I was wondering... what the hell is that second (smaller) port on the petcock for?? I'm guessing I just plug it since whatever it's for I dont have on my bike.

[yamaha_george]

I'm still doing mock-up and right now I'm on the tank. I know that the red fuel hose connects to the brass colored nipple on the petcock but there is a smaller nipple and I have no idea what it's for. Do I just plug it?

Hi,
the brass tube is the gas line, the smaller one looks like a vacuum line for the pump?

[delvryboy]

Don't quote me, but I think the reserve is vaccuum operated?

[mxryder21]

Thanks for the replies! Soooo, if it IS a vacuum port what do I do to/with it??

[DonTZ125]

It's not the Reserve that's the issue; that's an in-tank pump with a level sensor and a 'Reserve' switch, like the FZR1000s have, plus a low fuel light.

I *think* the pump has a vacuum on/off tap; the pump comes on, but fuel only actually flows when the engine is drawing a vacuum. Looking at the parts fiches, the YZF600 carb boots have great long nipples on them. The hoses leading off #s 1-3 are plugged, while the #4 leads up to the tank.

The FZR carb boot have M6 threaded ports, plugged with bolts. You'll need to add a nipple of some sort to a convenient carb (#4, for instance) and run a hose to the pump tap. Motion Pro sells these - http://www.motionpro.com/motorcycle/partno/08-0219/

[mxryder21]

It's not the Reserve that's the issue; that's an in-tank pump with a level sensor and a 'Reserve' switch, like the FZR1000s have, plus a low fuel light.

I *think* the pump has a vacuum on/off tap; the pump comes on, but fuel only actually flows when the engine is drawing a vacuum. Looking at the parts fiches, the YZF600 carb boots have great long nipples on them. The hoses leading off #s 1-3 are plugged, while the #4 leads up to the tank.

The FZR carb boot have M6 threaded ports, plugged with bolts. You'll need to add a nipple of some sort to a convenient carb (#4, for instance) and run a hose to the pump tap. Motion Pro sells these - http://www.motionpro.com/motorcycle/partno/08-0219/

Whoa, instead of doing all that should I try to find a "gravity feed" petcock with ON-OFF-RESERVE to eliminate the need for vacuum?

I know there are two ports that I capped on the #3 & #4 carbs... would I be able to just run a hose from that port? The #3 & #4 ports I'm referring to were "T"d together but I'm not sure what they connected to.

[DonTZ125]

Whoa, instead of doing all that

?? All what?

I know there are two ports that I capped on the #3 & #4 carbs... would I be able to just run a hose from that port?

You'll need to add a nipple of some sort to a convenient carb (#4, for instance) and run a hose to the pump tap. Motion Pro sells these - http://www.motionpro.com/motorcycle/partno/08-0219/

Add $4 nipple to #4 boot, run hose to vacuum port. Stick M6 bolt in #3 boot.

[Ickis]

Don's solution is about the only one that's simple AND cheap assuming that's how it needs to be done (I don't have the shop manual on hand to confirm). However, from my understanding there is a button you'll need to find and hook up to the fuel pump. Given that the fuel pump, once low, cuts the fuel. Pressing the button turns the fuel back on.

The 95'-96' designs for fuel delivery are completely different from the later models.

The 95'-96' models have an entire circular plate that the fuel pump (in the gas tank) and petcock (outside the tank) are attached to. Whereas the newer model's petcock and low fuel sensor mount in separate positions on the tank. The circular plate is what allows you to access the fuel pump should you need to replace it. Now... the later model petcocks look like they may bolt up to where the older one goes, I don't know for sure. If that is the case, it would probably require the removal of the internal fuel pump. Which also means plugging the holes that the fuel pumps power wires go through. But this ultimately leaves you with no way of knowing when you're low on fuel. And judging once again based on pictures, it looks like the Low Fuel sensor from the newer models *MIGHT* be able to be mounted where the fuel pump wires go through if you cut the assembly a bit. However, you may be able to retain the 95'-96' low fuel sensor without the fuel pump, and hook it up to a dash light.

Either way, making the newer petcocks fit to your year tank will require more work than Don's solution.

[DonTZ125]

Depending on what MX has for a TCI and harness, the 'Reserve' switch may be unnecessary. Certainly, a FZR600 TCI won't be turning it off for any particular reason!

MX - What you might want to consider is to design and fab a 'Low level' light that comes on at some point. Otherwise, since there is no reserve petcock or pump alert, you'll have to watch your odometer like a hawk, and learn to use it as a fuel gauge.

[Ickis]

Is it the TCI turning it off or is it the low fuel/fuel pump assembly?

[mxryder21]

Depending on what MX has for a TCI and harness, the 'Reserve' switch may be unnecessary. Certainly, a FZR600 TCI won't be turning it off for any particular reason!

MX - What you might want to consider is to design and fab a 'Low level' light that comes on at some point. Otherwise, since there is no reserve petcock or pump alert, you'll have to watch your odometer like a hawk, and learn to use it as a fuel gauge.

Hey Don, I'm using the stock FZR600 TCI and harness, and the odometer will be my fuel gauge. I can't remember if my tank is an 'early' 600 tank or a 750 tank In any event, I couldn't find the right 600 diagram but the 750 showed the hose going to cylinder #1. If it doesn't matter which cylinder it goes to, I'll probably plug into cylinder #3 since it already has a port.

Pics:


What do you think Don? Will it work?

[DonTZ125]

Ickis - the TCI gets the signals from the level sender and the reserve switch, then decides whether to turn the pump on or off.

MX - that looks just about perfect! The 750 has it going to #1; the 600 has it going to #4. "What ever works, baby, what ever works!"

I can't remember if my tank is an 'early' 600 tank or a 750 tank

- same part numbers, same piece of equipment.