I got a fuel pressure gauge kit from Autozone a few years ago, it had the appropriate fittings to connect to the schrader valve.

If you want to depressurize, you could hit the needle on the valve capturing the bit of fuel in a cup, try not to get it on hot pipes, this is the way they check it at the AHDRA races for the Destroyer fuel compliance check.

Connect the appropriate fitting to the valve, then to the Gauge, power on and see what you get for pressure while IGNITION/RUN SWITCH ON but engine off, then start bike to see pressure at idle.

Before disconnecting, purge the built up pressure via the gauge or hose if there is a relief button.

 

Borrow a gas line pressure testing gauge from Autozone. Attach it to the schrader valve and turn the ignition on. Read gauge. Could not be simpler.

 

Step 1: Position Class B fire extinguisher within arms reach from motorcycle...

 

I do that, a 10BC extinguisher right next to the bike and I work outside when I do this sort of work.

 

You can't get a meaningful fuel pressure measurement from a disconnected fuel line because neither sees the regulated pressure:

the supply line is upstream of the pressure regulator
the return line is the fuel that the pressure regulator "dumps"​

Either of these linked items will connect to the Schrader fitting in the fuel rail and measure fuel pressure as described in the manual:

Sun Pro fuel pressure tester
OTC 5630 fuel pressure tester

 

You can't get a meaningful fuel pressure measurement from a disconnected fuel line because neither sees the regulated pressure:

the supply line is upstream of the pressure regulator
the return line is the fuel that the pressure regulator "dumps"​

Either of these linked items will connect to the Schrader fitting in the fuel rail and measure fuel pressure as described in the manual:

Sun Pro fuel pressure tester
OTC 5630 fuel pressure tester

You misunderstood what I am proposing. I do not have a fuel pressure guage with the bleed off valve shown in the Service Manual. You are supposed to turn the engine on with the fuel pump electrical connection disconneted to drain it of fuel before installing the fitting of your pressure guage to the bike. After taking the reading you then have to bleed off pressure before detaching the guage at the Schrader valve.

I was proposing instead to bleed off system pressure by disconnecting either the pressure or return lines from the tank. I have done this plenty of times without anything bad happening. Doing it this way would require less specialized equipment on the fuel pressure guage. I have a pressure guage for my BMWs but I don't have the specialized fitting for the V-Rods Schrader valve and don't really want that whole contraption shown in the Service Manual.

Btw, why can't HD use the same fittings on all of their bikes? Ugh.

 

Why not bleed off the pressure at the shrader valve? It doesn't get much easier than that. The fuel pressure gauge that fits V Rods is one for a Chevrolet vehicle, just screws onto the shrader valve and when you unscrew it, it automatically bleeds off the pressure. Just wrap a rag around it when unscrewing to keep fuel from spraying on stuff. I have a permanently mounted fuel pressure gauge on mine left over from when I had a turbo on it and it comes in handy to make sure my fuel system is up to snuff.

Mike

 

Simple bleeding can be done by pulling the fuel pump fuse and trying to start the engine.
I bought an cheap R12 line (ebay) with fitting and slapped on an a gauge for the range I wanted. I found it takes 2 key cycles to reach full pressure. Probably the long lines with some expansion properties, compared to the short system of the BT engines that reached full pressure on one key on.
Prior to disconnect, pull fuel pump fuse and attempt engine start. This drops the pressure.
Frankly I've not found a whole lot come out with just direct hook up and removal. Extinguisher handy is a good idea regardless of method.
Ron

 

Simple bleeding can be done by pulling the fuel pump fuse and trying to start the engine.
Prior to disconnect, pull fuel pump fuse and attempt engine start. This drops the pressure.
Frankly I've not found a whole lot come out with just direct hook up and removal. Extinguisher handy is a good idea regardless of method.
Ron

Even on most cars there is not a lot of fuel that comes out to release the pressure, it is not very compressable.
However, it is very flamable and toxic. This is why all manuals must cover removing the pressure before connecting or disconnecting the test equipment.

 

I blew off bleeding the pressure from the lines, connected my fuel pressure guage to the Schrader valve and bled the bubbles from the fuel line with the engine running. It has a nice steady 60 psi regardless of throttle setting. Then I shut the engine off and unscrewed the fitting. A few drops of gas came out but otherwise no crisis. HD's procedure is unnecessary.

I also haven't solved the original problem. Sigh.

 

. HD's procedure is unnecessary.

Not from their lawyers point of view :deal:

 

Have you replaced the injector? I chased one of these misfires for weeks in the vrsca. Finally threw my hands up and put in a new injector and it stopped. I think the injector would not fire correctly.


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I don't have a spare injector floating around and don't want to start cannibalizing my other low mile perfect V-Rod. The nearest dealer is 85 miles away. Are the V-Rod injectors shared with any other model Harley or car?

 

http://www.ebay.de/itm/Fuel-Pressur...r-Schrader-Adapter-NEU-/300906490828?pt=Spezielle_Werkzeuge&hash=item460f6cabcc

 

You could swap the injectors front to back and see if the problem moves to the other cylinder. That would be pretty definitive I would think.

Mike

 

And a LOT less aggravating pulling the cam cover :notworth:

 

I checked a pair of my old Destroyer Injectors, they measure 15 ohms across the pins.
I also checked the newer set I installed last year also 15 ohms!

 

The bike is at the dealer. I found low compression. I should know more later this week.

I did a little research on fuel injectors and those for ECMs using low cost and stable "saturated charge" technology have high impedence, 11-16 ohms.

Depending on what failed and why I may return the engine to stock.

 

what is the spec for the fuel pressure anyway? i assume it's checked w/ key on - engine not running?

 

Fuel pressure should measure 58.5 psi (±3.5 psi) at the Schrader valve with the engine running. Pressure should remain steady as the engine speed changes (vary throttle position).

 

So, any news from the dealer on this? Been a couple of weeks and I'm curious as to the cause.

Mike

 

The bike jumped timing, and this allowed carbon build up on some valve seats, hence the low compression. Looks like the dynamics of these cams at speed and a worn, 40K mile, cam chain were not a good combination. Valves and seats will be cleaned up, there is no obvious damage (I rubbed the crud off some of the seats with a finger nail and everything looks fine underneath ), all crucial dimensions for valve guides, valve stems, spring height and tension and valve stem protrusion after the valve grind will be measured. Of course the cam chains and guide rails will be replaced. I am returning to the stock cams and throttle body, so the bored TB and SE cams will be for sale soon.

 

when the valves are out you can easily check if the stems are bent by rolling the stem on a flat surface and visually checking the valve disc for deflection, you don't need an indicator to make this test

I had about 4 bad out of 24, that's quite a lot

 

24 valves, was it an in line six in a car? Did a timing belt let go? I hate what I call "rubber band" cam drives but both of my cars have them.

 

All 24 were VRSC valves, I have eight spare cylinder heads which I purchased used for little money and overhauled myself over the years

They didn't show signs of mechanical Impact and yet they were not straight.
Cant telly you why, maybe heat, maybe "OEM eastereggs", or too much time on the limitter

 

All 24 were VRSC valves, I have eight spare cylinder heads which I purchased used for little money and overhauled myself

They didn't show signs of mechanical Impact and yet they were not straight.
Cant telly you why, maybe heat, maybe "OEM eastereggs", or too much time on the limitter

Very interesting. The tech working on my bike and I talked about this. I mentioned laying the stems on a glass surface to check straightness but he wants to use a dial guage.