Huge fuel leak, heals itself perhaps??? - K-Bikes.com - Excellence in Motion
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post #1 of 10 (permalink) Old Jul 16th, 2019, 11:37 pm Thread Starter
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Huge fuel leak, heals itself perhaps???

Hi,

I've had my K1300GT opened up a bit to install a power commander. Unfortunately, I clumsily broke part of the plastic fuel rail and so acquired a replacement from Ebay.

I put everything back together and fired the bike up before as a test before reinstalling the fairings. All was well until I noticed a pretty big trickle of fuel exiting the bottom of the bike. I shut it down and thought about what I might have missed during installation. Nothing came to mind.
So, one day later I took out the airbox and hooked up the tank so that I could see if I could see the leak when the fuel pump powered up. I did this and the leak seemed significantly less, and I couldn't actually see where the fuel was coming from.

Thinking on this a bit more, I remembered that the o-rings between the segments of the fuel rail did not seem that tight. In retrospect I probably should have replaced them, but they're quite a hassle to get to now.

Is it possible that these o-rings are swelling now that they have been exposed to fuel again after some unknown amount of time sitting dry? Is it possible this leak will seal itself in another day? Does anyone have any experience of something like this?

Obviously, if there's something I might have missed feel free to point it out, but it's not super complicated. The hose from the tank goes to the center section of the fuel rail, then there are o-rings sealing that to the two "arms" of the rail that each go to two injectors. There's one more o-ring to a pressures sensor. I can't actually see any leaking, but it is hard to see in there and impossible to get fingers in to poke around...

I guess I can order new o-rings and spend an evening taking it all apart again, but I'm tempted to wait and see if the leak is gone in another day!

Regards
Doug
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post #2 of 10 (permalink) Old Jul 17th, 2019, 8:02 am
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If you reused the O-rings I would simply replace them. Also, since you have to take out the fuel tank, replace the quick release on the tank with the metal set. It may be a hassle to replace but think about what happens on a hot day with a hot bike and a fuel leak out of the bottom.

2009 K1300 GT
1984 Kawasaki ZX750-E1 Turbo
1990 Kawasaki ZX600R
2005 R1200 RT - gone
2008 Honda CBR1000 RR - gone
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post #3 of 10 (permalink) Old Jul 18th, 2019, 2:52 pm
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I assume you've had the tank out, using the quick-release on the feeder line. (I read that) the QC o-ring is notoriously fragile and easily be damaged.

Replacement metal QC's are available; I put in one pre-emptively from https://www.euromotoelectrics.com/pr...-qdc735kit.htm

No affiliation, etc.

One "automatic it fixed itself" mode may be a massive fire. Suggest to find/fix before further riding!
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post #4 of 10 (permalink) Old Jul 21st, 2019, 9:57 am Thread Starter
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Well, this is interesting... I took things apart and replaced the o-rings and, when I was at it, the plastic quick release fitting (though it was visibly not the cause of the leak).
I put it all back together and switched on the ignition, feeling quite pleased with myself for getting the airbox back together a bit more quickly this time around.

Then, again, there was a strong trickle, almost a gush, of fuel leaking from the bike. The leak reduced very quickly to a drip. This was accompanied with an initial hissing noise as if air was escaping as the fuel rail was being filled. It reminded me of the vacuum breaker in a sprinkler system, actually.

So, one thing that's left is the fuel pressure sensor. Does that thing contain a spring/diaphram arrangement to act as an an accumulator to smooth out fuel pressure pulses? Do these things ever leak? I wonder if it has a leak that gushes at low pressure then much less so at pressure.

Obviously I'll take it apart again, but it's not as easy to see what's going on with that bike as it is with an R bike!

cheers,
Doug
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post #5 of 10 (permalink) Old Jul 21st, 2019, 12:03 pm
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Fuel pressure sensor

This is all I found. Do you have a repair manual?

O-ring part # - 13 53 7 688 284 O-RING - 9,25X1,7 $10.53
Attached Files
File Type: pdf Fuel pressure sensor.pdf (431.9 KB, 2 views)

2009 K1300 GT
1984 Kawasaki ZX750-E1 Turbo
1990 Kawasaki ZX600R
2005 R1200 RT - gone
2008 Honda CBR1000 RR - gone

Last edited by TF1200RT; Jul 22nd, 2019 at 1:44 pm.
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post #6 of 10 (permalink) Old Jul 22nd, 2019, 11:43 am Thread Starter
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I took the fuel rail apart yesterday and did not see any obvious signs of trouble, or previous leaking from the fuel pressure sensor. It looked good.

So, I carefully re-assembled everything using a very light smear of o-ring silicone grease to allow it all to go together well. The rail seemed to seat on the injectors nicely, but required a fairly firm push onto each injector. I was less convinced about the quality of the seal at the larger o-rings on the fuel rail. They seemed snug, but not really snug.

The leak still persisted after re-assembly. I wonder if there's something funny about the seating of these larger o-rings? Is it possible they weren't seated correctly, but (at least sometimes) manage to get sorted out somehow after some leaking?

The bike doesn't seem to power up the fuel pump without a bunch of airbox related stuff plugged in, and then it gets impossible to see what's going on. I think I may have to figure out the connections to power up the pump directly for troubleshooting purposes. It's too time-consuming to continue to monkey around "in the dark" like this.

This is testing my patience and maturity! (And I do have some maturity on my side...)

cheers
Doug
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post #7 of 10 (permalink) Old Jul 28th, 2019, 3:18 pm
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There is a fuel pump recall for leaking at the quick disconnect boss on the fuel pump.
The new pump has a metal reinforcement ring around it (not a clamp type)

When my pump leaked it tended to leak after engine got hot. In retrospect I should have let leak an the insurance buy me a new bike.

'07 K1200GT Crystal Gray Metalic
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post #8 of 10 (permalink) Old Yesterday, 12:35 pm
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This happened to me once. It was an injector oring that got nicked. If you did not use oring lube the first time, it may have happened then.

Mount Vernon, WA.
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post #9 of 10 (permalink) Old Yesterday, 5:22 pm Thread Starter
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I had a chance to take it apart again and this time I used compressed air to pressurize the fuel rail, while there was still some fuel in it. This allowed me to see a significant leak at the rightmost injector o-ring.
Disassembly showed no visible damage to the o-ring or the mating parts, so I reassembled with Corning 111 o-ring lube, and there is now no sign of a leak. I can only assume that the o-ring was not seated properly and earlier partial "self healing" was the o-ring shifting into a better position??

It's certainly no my first time dealing with injector o-rings, but I guess this shows there's still more to learn!
cheers
Doug
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post #10 of 10 (permalink) Old Yesterday, 11:22 pm
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I too use Dow Corning O-ring lube, good stuff, but also there is red rubber grease or some engine oil if nothing else is on hand. But I'm anal and have a shelf full of stuff. Point is those injector O-rings are snug and the surface is not silk smooth in the injector, lube is needed. Glad you found a frustrating problem.

Mount Vernon, WA.
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