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Buell Forum » Old School Buell » Archive through April 26, 2013 » X1 EFI Fuel System Diagnosis & Repair Part III « Previous Next »

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Buellx1w
Posted on Sunday, April 21, 2013 - 09:42 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Part III

OK, at this point you know you have no fuel delivery from the pump assembly. Here are the possibilities (assuming you know you have fuel, and the pump whirrrrs) ..

1. a blockage on the pump intake, output line, or petcock.
2. a bad fuel pump
3. a bad pressure regulator (PR)
4. this is the sneaky one- a LEAKING regulator!

Pull the assembly (see service manual). Ruling out the fuel pump itself isn't easy because setting up a test rig outside the tank can be difficult. Just remember- SPARK and FUEL can be a serious problem outside of a combustion chamber! And a 12v supply can easily create a spark. Refer to other posts to test the pump but remember don't test it with gasoline outside the tank. I've read that some test with alcohol (no not beer!) which is probably a better choice which won't contaminate the pump.

Another source of problem is the intake screen/filter. It tends to disintegrate and gum up the pump after many years. Inspect it. While you're there, replace it if its old. HD sells them separately.

If you need a pump, fuel-pumps.net was very helpful for me and offers local pickup in central Fl. Walbro WALSCA210 can be had for under $100, which is a direct plug-in replacement. note this is JUST the pump- not the whole Pump/PR assembly.

As far as blockage- once the pump is off you can attempt to blow air thru the output and see if it it blocked.

Now for the tricky part which had my bike down for weeks as I chased other ghosts.. The Pressure regulator (PR) is leaking.

The Buell PR is, more accurately, a waste-gate which operates just like a turbocharger waste-gate except it vents fluid instead of air.

The pressure regulator (PR) is the round part held down by 2 screws.

The pump pressurizes the regulator to, presumably, something over 50PSI. At or about 50PSI, the PR begins to open to vent pressure back into the tank until it drops back to 50PSI. Tank pressure is relieved with the cap vent.

The PR should fit snugly in its cavity- it should not rock or be able to be turned. It's constrained by 2 sets of O-rings; one small on the base, and a large one around the body. To inspect it, remove the 2 screws and carefully remove it.

If these start leaking, you'll first discover the bike starts to break up at hi RPMs, because it can't supply enough fuel to the injectors on hi-demand.

As the symptons get worse, you'll find that the bike runs worse and worse, then won't idle, then won't start.

The EZ fix is to just replace the O-Rings. But I was so sick of pulling this FP, I just replaced the whole Reg and O-Rings. Plus- HD doesn't sell the O-Rings seperately. Of course!

Once re-assembled, you can check the pressure with a suitable FP gauge. Harbour Freight sells them for under $50. Or, as I did, borrow them from a buddy.

The SNEAKY part of all this is the symptoms indicate a component fail like a pump, regulator, filter. But instead its really just a LEAK, but not a leak you can see , because it leaks BACK into the tank.

It's such a pain to get the pump out and fish it back in, I recommend, if it original- just replace the pump and PR and O rings. You can do all of them for under $150 and you'll be good for the next 30-40K miles.

Be sure the connectors are tite and secure of course- remember the advice about sparks! You DO NOT WANT these to fall off -it could be very dangerous.


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Greg_cifu
Posted on Sunday, April 21, 2013 - 11:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hmmm...so I DID call it correctly: same failure as my Excelsior Henderson and the designs are so similar that I have to believe the pump assemblies are from the same supplier. Couple of points:

1) Since you are already a patron of Harbor Freight, their giganto O-ring kit had ones in there that were close enough to work fine. If HD sells the regulator separately, jump for joy 'cuz on most bikes, you have to buy the whole pump assembly to get the regulator.

2) You still missed one or two more O-rings. That plastic regulator manifold somehow attaches to the fuel pump (hard to tell from your photos). On the Excelsior it slid down two 1/4" rails and was held in place with circlips. I see a huge zip tie on yours. Maybe that's it. In any case, the snout on the fuel pump has one or two sealing O-rings that go into that plastic regulator manifold. If the regulator's O-rings failed, those can't be far behind. Time to pull it and have another look-see.
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Jramsey
Posted on Sunday, April 21, 2013 - 12:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Regulator/fuel pump housing is Aluminum.
Pump has rubber sleeve/bushing, no o-rings.



H-D only sells a complete assy.




I'd git rid of the cable tie and use the proper clamp.



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Greg_cifu
Posted on Sunday, April 21, 2013 - 01:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Whoa! Wait a minute! That clamp is all that keeps the pump from SLIDING away from the manifold? Nothing else? Yeah, I wouldn't trust that zip tie for a minute. Man, that's just going to slide apart and strand him without warning.

Is that rubber sleeve on the pump snout original? My Excelsior had a long o-ring groove there. One bike had a single o-ring, the other had two.
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Wack01
Posted on Wednesday, November 27, 2013 - 07:18 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Where did you buy the pressure regulator? thanks
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