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TOPIC: ZG1300 running much to lean

ZG1300 running much to lean 2 months 2 weeks ago #24604

  • Kawboy
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Phil wrote: Hi Gavin, I fitted an adjustable fuel pressure regulator to my ZG some years ago, but there's a guy on the European Z1300 Facebook page that's fitted a Herko PR4055 fuel pressure regulator that's pre-set to 45 psi & he says it works fine, I've set my adjustable regulator to about the same pressure & it runs better. Can be found on Ebay & is pretty reasonable at about 15 quid. As far as fuel pumps go I fitted a Pierburg automotive fuel injection pump some time ago too, wasn't cheap, but there is a cheaper alternative, search for "Holden Commodore VL Main EFI External Fuel Pump RB20E RB30ET 070" on Ebay, that will do the same job.

I'm a little concerned with the Holden pump. It's rated to feed a 5.0 L V8 engine which is almost 2-1/2 times more fuel than the ZG would need.
I found a fuel pump on EBay for Kawasaki Vulcan 1500 that I think would be more in line with the fuel needs of the ZG. See
EBAY inline fuel pump

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Last edit: by Kawboy.

ZG1300 running much to lean 2 months 2 weeks ago #24606

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Well I went to the bike this morning and the fuel pump that didn’t work yesterday now does( we don’t know how long this pump has been dry as it came in a box of spares) , anyway I have done more pressure test with exactly the same results as with the original
Ignition on pump priming = 33psi
Tick over = 30 psi
4500rpm 28psi

There doesn’t appear to be any leakage apart from what normally occurs when switched off as after several minutes the pressure has only dropped 5psi.
I have been thinking on what gives the required pressure other than the pump and regulator or leaks , could a weak tank return valve cause the drop as it is only a few psi, I know a blocked one causes over fuelling so in theory a weak one or not being able to fully close would cause an opposite effect

Cheers Gavin

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Last edit: by Gavin.

ZG1300 running much to lean 2 months 2 weeks ago #24610

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Kawboy wrote:

Phil wrote: Hi Gavin, I fitted an adjustable fuel pressure regulator to my ZG some years ago, but there's a guy on the European Z1300 Facebook page that's fitted a Herko PR4055 fuel pressure regulator that's pre-set to 45 psi & he says it works fine, I've set my adjustable regulator to about the same pressure & it runs better. Can be found on Ebay & is pretty reasonable at about 15 quid. As far as fuel pumps go I fitted a Pierburg automotive fuel injection pump some time ago too, wasn't cheap, but there is a cheaper alternative, search for "Holden Commodore VL Main EFI External Fuel Pump RB20E RB30ET 070" on Ebay, that will do the same job.

I'm a little concerned with the Holden pump. It's rated to feed a 5.0 L V8 engine which is almost 2-1/2 times more fuel than the ZG would need.
I found a fuel pump on EBay for Kawasaki Vulcan 1500 that I think would be more in line with the fuel needs of the ZG. See
EBAY inline fuel pump

The fuel pressure regulator maintains rail pressure regardless of what is supplied form the pump, excess is put back into the fuel tank via the fuel return line. The Pierburg pump I fitted to my ZG was originally intended for a Volvo 3.0 V6 & has been fine. Looking at that VN1500 pump you'd have to do a bit of extra plumbing to make it work as both pipe connection stubs are on the same side.
Only dead fish go with the flow

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ZG1300 running much to lean 2 months 2 weeks ago #24611

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Gavin wrote: Well I went to the bike this morning and the fuel pump that didn’t work yesterday now does( we don’t know how long this pump has been dry as it came in a box of spares) , anyway I have done more pressure test with exactly the same results as with the original
Ignition on pump priming = 33psi
Tick over = 30 psi
4500rpm 28psi

There doesn’t appear to be any leakage apart from what normally occurs when switched off as after several minutes the pressure has only dropped 5psi.
I have been thinking on what gives the required pressure other than the pump and regulator or leaks , could a weak tank return valve cause the drop as it is only a few psi, I know a blocked one causes over fuelling so in theory a weak one or not being able to fully close would cause an opposite effect

Cheers Gavin

Not really, that valve serves only to stop fuel leaking out when the tank is removed.
Only dead fish go with the flow

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ZG1300 running much to lean 2 weeks 3 days ago #24978

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Hi everyone
Bit of an update on my Fuel injection woes,
After fitting an adjustable regulator the porcelains are now the right colour although a little bit of soot around the edge of the metal ring, however I still have tick over problems.
1)When fully warmed up on tickover and set at 1500 rpm the revs are at 1500 then drop to 1000 then build back up to 1500 then drop to a 1000 so on and so on.
2) When riding if I pull the clutch in and slow down on the brakes It does as stated above, however if I slow down using engine breaking then pull the clutch before I stop the bike cuts out every time.
3) when actually riding at any speed the bike runs smoothly, I did a top gear rolling 40mph test today just wound the throttle straight back and there was no hesitation from 40 to 100mph ( only stopped at a 100 because I ran out of straight road.
Any views from you guys to why the tick over is so crap, by the way new filter and injectors have been cleaned, tested and are virtually the same across all 6 with good flow and spray pattern

Thanks in advance

Gavin

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ZG1300 running much to lean 2 weeks 3 days ago #24983

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Hi Gavin, are the throttle bodies balanced?
Only dead fish go with the flow

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