Yamaha Turbo Fuel Pump Regulator

Anyone know of an aftermarket replacement?
Couldn't find one on XJ4Ever.
Ths

 

you could try this one
https://www.holley.com/products/fue...regulators/carbureted_regulators/parts/12-887

I read on the turbo forum another guy used it. Its adjustable between 4.5-9 psi but the poster said he was able to adjust it down to the 3 psi range needed.
I did my own research, called up the listing on Summit Racing, plugged in the criteria and this was the cheapest one checking all the boxes.
Another one appears to be the same thing only chrome.
https://www.holley.com/products/fue...regulators/carbureted_regulators/parts/12-881

It first puzzled me what to do with the outlet port but this would just get plugged if it was mounted in the same place as the OEM.
It could be mounted before the check valve (which is a more conventional automotive configuration) but then you would need to cap the output on the check valve, same difference.

Nothing I've found is as compact as the OEM Yamaha FPR so the routing would likely need to be reconfigured once a suitable place to hide it is determined.
There are probably 1,000 different model specific FPR's in the automotive world that look like the Yamaha but of course they don't list the specs, they are not adjustable, and they are set up for fuel injection with much higher pressures.

What is wrong with yours?
There is actually a new original OEM Yamaha one on eBay now for $291.99.

 

Running 15 psi, it misfires when I use the boost. It's a fueling issue. The outside carbs are starved for fuel. The tank, petcock, and pump/filter are fine (I removed the stock filter and run an inline). It's down to the regulator not supplying enough fuel at boost. I'm looking for a rising rate 1:1 FPR that can be adjusted down to 3 psi as you mentioned. An OEM may do the same thing as it is not designed to work at 15 psi. Thx for replying.

 

Checked the Holley site. The only FPR that I saw that has any type of chance of working is this one:
https://www.holley.com/products/fue...regulators/carbureted_regulators/parts/12-880.
It's a rising rate 1:1 that can be adjusted down to a 4 psi base rate. Without the rising rate feature, a FPR set to a 3 psi would only work at idle or 0 or less manifold pressure. As soon as boost is added and the carbs pressurized past 3 psi, fuel would not enter the carbs. At full boost using the 15 psi blowoff valve, 18 psi is required to fill the carbs. A non-rising rate FPR will not work.
If you'd like to see what a properly-fueliing stock Yamaha Turbo can do go to and turn up the volume!
That's 90 RWHP at 15 psi and almost 70 ft/lbs of torque. The charts are here http://www.turbomotorcycles.org/Images/ytdynochs.jpg.
From the factory without the Power Up Kit they made 70 RWHP, but 90 RWHP is so much more fun!

 

What fuel pump are you running? The OEM is only rated for 14.2 psi.
Also, what in-line fuel filter have you installed?
I had fuel starvation with an in-line filter.
Have you tried running without it?

The FPR I referenced is 1:1.
Connecting the boost port on the FPR to the manifold pressure will provide the rising rate.
The OEM FPR will maintain 2.8 psi fuel pressure above whatever boost pressure you have.

I would 1st measure what your fuel pump is capable of.
If it is capable of 18 psi then look at the filter.

Remove the fuel return line from the petcock and dead end it into a pressure gauge.
You don't need the motor running, following a tip from @ManBot13

 

I am running the stock, original fuel pump. Volume is more than enough.
Haven't put a gauge on it, but from checking the flow I'd say it's at least 14-15 psi.
The starvation problem exists even without using the boost.
I am running an oversized, automotive, paper element in-line filter.
I removed the stock FP filter as it fills with debris regularly and installed the in-line trying to eliminate the problem.
Didn't help.

These bikes don't begin to build serious boost until 6000 rpm. It happens even when running easy up a long hill with 4 psi on the boost gauge.
I called Holley (they are very helpful) and was told the FPR I should use is the 12-879 with a 4-15 psi range. The 880/881 only goes to 9 psi.
I was also told over-boosting the FPR will damage the diaphragm as they are only rated to the specified psi.
Who used the 880/881? I would like to know how much boost they are running and how that FPR worked for them.
Does anyone know the max psi rating of the stock FPR?
If so, what is it?

Thx for your help.

 

Look closer at Simmy's last post. If you're running 15psi of boost with the original fuel pump, it explains your starvation, or at least it could.

You have to remember that you are running with pressurized, blow through carburetors. Instead of the fuel bowl being exposed to atmosphere, and the pressure drop in the venturi drawing fuel, the venturi is exposed to boost pressures, so the pressure in the carb bowl must be increased to compensate. But because it's a carb, everything has to be balanced to work. Hence, the pressure regulator. It doesn't regulate to a fixed pressure, but instead regulates to 2psi over the boost pressure. That 2psi allows the bowls to refill through the boost range.

If your fuel pump only puts out 14 psi, then you can only boost up to 12psi. Your bowls won't fill over that unless you add more fuel pressure. If you're going for more, I'd recommend a fuel pressure gauge (they run a little over $100 with an electronic sender). I had one on my Turbo with a stock fuel pump so I'd never be surprised by a pump or regulator failure, especially after installing a manual boost controller. But I only ever set mine to 11psi.