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Any 550's out there running with no fuel pump?

Started by kiwibum, November 12, 2007, 02:02:07 AM

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Rikugun

I may have interpreted "easier cold starts" too literally. I was assuming any start begins with full carb bowls. So it's just a matter of how you arrive there - turn the key or turn the petcock to "Prime" and wait a bit. I have the same experience without the tick, tick, tick. If it's been run recently the bowls are full. If not run in a while I turn the petcock to prime and wait 30 seconds.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

MikeScoot

#21
Quote from: Rikugun on June 01, 2020, 06:34:54 AM
Mike, your "air filter on top" idea is one I haven't heard before. How serious are you about this? Still in a theory stage or have you worked on any prototypes or mock-ups?
Hi Rikugun,
Na, it was just a whacky idea. Could probably work pretty well but the work involved to do it would be more than I can afford.

With regard to the cold starts; I think the reason an electric pump may be better for cold starts is that it would bring the bowl levels to the appropriate height before the motor was even cranked (depending how it was wired). With a mech. pump it would require cranking to pulse the diaphram in the pump before any fuel could be moved. Just a guess.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

Rikugun

You don't have to crank a Vision over to fill the bowls. That's what the petcock's "Prime" position is for. There is a slight delay while you wait for the bowls to fill however. I can see Walt's point that it's easier (I now interpret as faster) especially after storage with empty bowls.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

MikeScoot

#23
Doesn't the fuel still have to push its way through the pump even when on prime?
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

jefferson

An experience I had with non ethanol fuel gave me much easier cold starts. Highly recommend not using ethanol fuel if you can find ethanol free. If the bike had been sitting for very long it would take a while to start, but with ethanol free it would crank right up. Put it down to the ethanol fuel evaporating while the good stuff didn't. I also lost 5 mpg going from ethanol free to the ethanol blend.

Walt_M.

Freedom is a wonderful thing. Everyone can do what they want. I am running an electric pump.
Whale oil beef hooked!

fret not

Low pressure pump if you are going to use an electric pump.  I found one with a range of 2  - 4 pounds pressure.

Another thought regarding making a tank is to make the air box before beginning to plan the tank.  In my brother's efforts at the Bonneville slat flats he learned about the importance of air flow into the engine at speed.  The engine needs "calm" smooth (opposite of turbulent) air which is why there is an air box in the first place.  And the air box needs to be at least twice the volume of the engine displacement.  There are complicated programs to actually figure this stuff out if one wanted to dig that deep.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

MikeScoot

#27
Quote from: fret not on June 01, 2020, 02:11:28 PM
...the air box needs to be at least twice the volume of the engine displacement.

I agree, but I think a distinction must be made between the volume of the airbox and the volume of air after the filter.  I would suggest that the volume of air between the air filter and the point at which fuel is introduced needs to be as large as possible. The size of the airbox itself - before air is passed through the filter - makes little difference, in my opinion, because it presents no restriction to flow - with the exception of afterthought gadgets like the RK flapper. The air filter restrics air flow resulting in lower than atmospheric pressure between itself and whatever is used to introduce fuel. The greater the volume between the filter and the carbs/injectors the less this reduction in pressure will be, and the lower the fluctuations in pressure, and the lower the turbulence.
The XZ has a huge volume BEFORE the filter element.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

Rikugun

Quote from: Walt_M. on June 01, 2020, 12:25:46 PM
Freedom is a wonderful thing. Everyone can do what they want. I am running an electric pump.
Absolutely Walt. And I didn't intend for this to become an electric fuel pump bashing session. Actually, it's a cool mod. I imagine the install is straightforward and they are effective. With my Visions it's been a matter of priorities.  Fuel delivery wasn't an issue so my efforts were applied where needed. I'm not saying I'd never use one - just haven't had to yet.

Quote from: MikeScoot on June 01, 2020, 07:28:21 AM
Doesn't the fuel still have to push its way through the pump even when on prime?

Yes, the fuel passes through the pump on it's way to the carbs. I don't know that it would pass through an electric pump though? Provided you had enough voltage in the battery it wouldn't matter. As Walt said, turn the key and the pump charges the bowls with fuel.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

MikeScoot

#29
Quote from: Rikugun on June 02, 2020, 06:37:52 AM
... Yes, the fuel passes through the pump on it's way to the carbs. ...

So even on prime with the motor not running it must pass through the pump - by gravity alone. Not an ideal system - especially since the pump is located some height above the bowls.
I'm warming to the idea of an electric pump, or simply gravity feed without a pump, more and more.

Lol also warming to the idea of getting some sleep as I have to be at work in eight hours from now.

Looking foward to any other ideas on this topic over morning coffee tomorrow.

Mike
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

Rikugun

#30
I'm scratching my head trying to understand your reasoning here but maybe I need sleep too.  :)
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

MikeScoot

lolol  I'm just trying to work out why the XZ is somewhat notorious for being difficult to start and frequently runs badly. If we assume, for the time being, that the ignition system is not the problem then we are forced to assume that the cause of difficult starting is the fuel system.

We know that the tank is an odd  design and that the bulk of the fuel is held quite low. This would mean fuel exiting the tank through the petcock would often be under less pressure than that on a more conventional tank.
We know that the bike will run, by available accounts, quite satisfactorily with no fuel pump - but that when the fuel level is low there is not enough pressure through the fuel line.
We have several reports that the fuel system seems to operate very well with an electric pump and these reports claim the electric pump enables better cold starting than the mechanical pump.

So whilst mechanical pumps are, under normal conditions, quite reliable, it seems reasonable to wonder whether the XZ mech. fuel pump set-up is doing a good job of supplying fuel at a satisfactory pressure at all times or not.

lololol I probably wouldn't even be thinking about this if my bike was running well! :-)  But even if it was, we still know the XZ can often be a mongrel to start - and that's a PITA on any engine.

Oh, and another possible factor mentioned in this thread was ethanol fuel.

:-) Off to think about blue sky, flowers, big diesels and narrow winding roads now. :-)

Mike
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

kiwibum

It is very easy to isolate the fuel pump as causing running problems, put in a direct line from the petcock to the carbs and test with a full tank of gas. I doubt low pressure from low gas level makes enough difference to notice, my bike ran fine when doing run tests with a small plastic bottle of fuel so I could run with out the tank on. One thing that will make a big difference is having a good filter in the fuel line and flushing out the fuel tank properly (same for any old bike).

I don't know if there is ethanol in the gas in Australia but this is another problem to be aware of as someone else mentioned. "Ethanol is hygroscopic, meaning it absorbs water vapor directly from the atmosphere" (https://en.wikipedia.org/wiki/Ethanol_fuel#Post-production_water_issues). So if you have a ethanol fuel mix and the tank is half empty for the week sitting in a cold garage you can have starting and running problems due to moisture.

Regarding "the XZ can often be a mongrel to start", I think for new owners this is partly learning the best starting technique. The XZ has an accelerator pump like a car so it only needs one twist of the throttle during starting otherwise it floods. For me I found the technique was one flick of the throttle, hold the throttle partly open then hit the starter. Most people are used to twisting the throttle at each kick/push of the button. I also found cleaning up all the electrics connections including earthing wires solved starter motor issues.

What it really comes down to with these bikes (or any old electrical-mechanical system) is taking a methodical approach and isolating each area to remove it from the equation to find the real cause of the problem. My bike ran great once I fixed all the little problems it had.

MikeScoot

Quote from: kiwibum on June 02, 2020, 06:25:53 PM... The XZ has an accelerator pump like a car so it only needs one twist of the throttle during starting otherwise it floods.

Yes, they do flood easily once the system is primed well. I find simply leaving the choke on and leaving the throttle alone works well on most bikes. Once actually fired up a few gentle caresses of the throttle are sometimes needed. Same method worked well on a near new XZ I had back in '84 - also on my VMax.

Also agree that a methodical approach is almost always essential when troubleshooting anything.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

Rikugun

I think KIWI makes a great point regarding starting rituals and electrical connections - these cannot be ignored.

Mike, I'm still confused why you think fuel passing through the stock pump to fill the carb bowls is a bad thing? Also, please forgive my OCD. These threads become a record others will use so allow me to question what seem to be a couple of presuppositions? Your comment regarding only fuel system and spark required is true-ish. It's reliable spark at the right time. I'll assume air is included in the "fuel system". Compression was left out of the holy trinity and has to be considered in diagnostics too.

QuoteWe know that the bike will run, by available accounts, quite satisfactorily with no fuel pump - but that when the fuel level is low there is not enough pressure through the fuel line.
Is this what's called a straw-man argument?  :) That's why a pump was provided by the factory. Leave it in and there's no problem. Or, replace it with electric if you prefer.  "...run quite satisfactorily w/no pump..." if you accept limitations not present with the stock setup.

QuoteWe have several reports that the fuel system seems to operate very well with an electric pump and these reports claim the electric pump enables better cold starting than the mechanical pump.
Define "better". All things being equal, 2 bikes with properly filled carb bowls should start equally well. The universe doesn't care if one has a pulse (not mechanical) pump and the other electric. If, both bikes had empty bowls, the electric pump would fill the bowls faster than the OEM setup switched to "Prime". Once full, they start the same.

QuoteSo whilst mechanical (pulse) pumps are, under normal conditions, quite reliable, it seems reasonable to wonder whether the XZ mech. fuel pump set-up is doing a good job of supplying fuel at a satisfactory pressure at all times or not.
You can wonder but you'd have to demonstrate how reasonable it is. I don't see sufficient data to support that claim.  The pump has a regulator and internal by-pass ('83's have a return as well) to supply sufficient flow and pressure to work as designed. And, they've demonstrated over decades to do just that.

No one will judge you for installing an electric fuel pump but don't bash the OEM setup unnecessarily. Visions have enough legitimate issues to bash!  :P Hopefully I haven't interjected personal bias into this but let me know if I have.



It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Ken Williams

I offer potential evidence that engine starting could be easier with an electric or no fuel pump.  I had ongoing trouble with my 83 that I eventually resolved by replacing diaphragms in the fuel pump.  During troubleshooting I discovered no fuel moved through the pump unless the engine was turning.  Hopefully, fuel will flow through a pump with good diaphragms so the carbs can be filled in a stationary engine with the petcock in prime.  Perhaps someone owning a Vision with the OEM pump will find an opportunity to check. 

Fuel pressure in the 83 is regulated by the height of the return line, located close to the top of the tank.  No internal by-pass is included. 

MikeScoot

#36
@ Rikugun;  I'm not quite sure what it is that you are really trying to demonstrate here, Rikugun.
I'm just interested in making my XZ easier to start and, perhaps, more reliable.
Whether we like it or not, several people here have brought forward information which appears, to me, to indicate the fuel pump may well be a reasonably common cause of, or factor in, starting problems.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

Rikugun

@Mike, Seriously not trying to challenge you or be disrespectful, Mike. My apologies. My criterion for evidence is often unrealistically high. Sometimes a few anecdotal accounts are all one has to go by. Moreover, as a wise prophet once said "Tread carefully as information from our USA cousins is not always right for other markets". I neglected to take this into account.

Ken, thanks for the comments. I can't speak to the '83's with any real experience as all mine have all been '82's  I will say all 3 of my 'RJ's filled the carbs with the petcock on "Prime" position.

The factory manual for the 1983 USA RK describes the procedure for removing the regulator cover with 3 screws, then the spring and diaphragm from the pump body. Sounds like the regulator is internal rather than external like the 1982 US RJ's. Do you recall seeing anything like that? It's apparently under the pump diaphragms and valves. Maybe you didn't dig that deep or maybe the manual is in error. It wouldn't be the first mistake found.

Yes, no internal bypass on the RK as it uses a return hose. I didn't make that clear enough in my previous post. Again, no practical experience here but from reading posts on the forum my understanding was the pump return went to the extra fitting on the petcock exclusive to the RK. In the US market anyways. Not so?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

kevin g

When I started work on my '83 I rebuilt the carbs and fuel pump and once I found the tiny fuel passage in the idle circuit that was clogged it starts just fine.  It doesn't jump to life like my fuel injected BMWs but it starts right up.

I have proof that fuel will flow just fine through the fuel pump.  I have drained my fuel tank several times by attaching a hose to the overflow spigot and opening the float bowl drain screws.  The tank drains down until the level is at its lowest possible level (where the pump would need to be used).

The Prophet of Doom


If I recall you reported you bike was awesome with a pony tank, and only crapped out when you used the real tank.  That tells me you have a problem that is reducing fuel flow. (For example  blocked/pinched fuel line, blocked pump, perforated diaphragm, blocked petcock, blocked filter screen)  Remember that hundreds, if not thousands of XZs work just fine without requiring an e-pump, so it's more a problem on your bike than an underlying design problem.

Electric fuel pumps are awesome.  Hop on the bike, turn the key and go.  Slightly higher pressure may help overcome reductions elsewhere, so whether it's a problem solver or no you aren't wasting your money.  Fixing underlying causes though will be cheaper and a better first approach.

If it's not correct that you bike is brilliant with a pony tank, then your list of possible causes just exploded.  Sync, mixture, blockages, vacuum leaks and spark are also all good candidates for poor starting and far more common that fuel pump/reg problems.  These units are insanely reliable.

XZ lives matter!