Author Topic: Yamaha XJ 900s Diversion 1998  (Read 2646 times)

Offline jon stead

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Yamaha XJ 900s Diversion 1998
« on: January 26, 2020, 11:08:32 AM »
Hi, my commuting bike is a 98 Yamaha 900s Diversion that is doing me proud in all weathers.

My problem is, that according to every specification I look at, the tank should hold 24 litres, giving a range of about 240 miles. I get about 10 miles to the litre so my consumption seems spot on, but I ran out of fuel after 135 miles the other day and it took about 14 litres to refill it.

I can’t say for certain how much fuel was left in the tank when it “ran out”, so it might’ve been that there was ten litres left in there.

There is no reserve setting on the fuel tap, only on or off. It is not a vacuum operated tap. There is an electric fuel pump.

The bike has a fuel gauge and low fuel warning light. As appears to be normal for this model, the fuel gauge is not reliable, so I use the odometer for my remaining range calculations. Apart from the light check at start up, I have never seen the low fuel light on.

When the weather improves, I am going to empty the tank and take the fuel tap off to see if there is an extended pipe or something inside that is reducing the amount of available fuel.

Another thing is that maybe the tank has had a huge dent in it that has been very well filled and repainted, but I doubt it’s this.

Anybody had any experience of this reduced range/fuel tank capacity on this model, or any other?
2015 Triumph Bonneville T100 Newchurch

Offline Tomb

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Re: Yamaha XJ 900s Diversion 1998
« Reply #1 on: January 27, 2020, 07:12:40 PM »
My winter/commuting bike is a '98 900S Divvy too, it gets lots more than that to a tank without running out and I have a heavy hand. The low fuel light does come on waaaaay after the fuel gauge says empty. Was the tank actually empty when you "ran out"? as in did you throw the bike about to hear the lack of sloshing sound from the filler hole? just thinking there may be a pipe fitted on the fuel tap to stop crap getting through.

I put 18 litres in the other day
Tom
'73 CB550 with CB500 engine café racer
'62 CB77 Sprinter
'70 CD175
'78 CB550 with sidecar
'80 Z50R
And a load of old Yamaha 1100's

Offline the-chauffeur

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Re: Yamaha XJ 900s Diversion 1998
« Reply #2 on: January 28, 2020, 03:07:38 PM »
Whilst you're looking into the issue, it might be worth taking a look at your fuel pump and pipe routing to check that assembly is working as it should.

I don't have any experience with Divi's, but I've had an early model Deauville (similar age to yours) in the past and they're known for having dodgy fuel pumps.  The symptoms aren't always obvious . . . 

 . . . what's s'posed to happen is that the pump drains the tank to empty.  But the Deauvilles will still work when the pump gives up; when that happens, the system behaves as though it's gravity fed. 

That works fine, right up to the point where the pipework from tank-to-pump-to-carbs is higher than the level of the remaining fuel in the tank (the rear of the tank sits comparatively low).  At that point, the bike dies despite there being several litres of fuel left because there's no way of forcing the remaining fuel to the carbs.

Check the obvious stuff first, but like I say, this might just something you add to the list . . .
« Last Edit: January 28, 2020, 03:10:10 PM by the-chauffeur »

Offline Tomb

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Re: Yamaha XJ 900s Diversion 1998
« Reply #3 on: January 28, 2020, 03:21:16 PM »
Just filled up the Divvy, the gauge had indicated empty for some time and the light had come on half a mile from the fuel station, £22.59 for 17.80 litres at £1.269 per litre. (receipt in my hand)

Before now I have run with the light on for a good distance looking for fuel and never got near 24 litres
Tom
'73 CB550 with CB500 engine café racer
'62 CB77 Sprinter
'70 CD175
'78 CB550 with sidecar
'80 Z50R
And a load of old Yamaha 1100's

Offline Tomb

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Re: Yamaha XJ 900s Diversion 1998
« Reply #4 on: January 28, 2020, 03:48:51 PM »
Whilst you're looking into the issue, it might be worth taking a look at your fuel pump and pipe routing to check that assembly is working as it should.

I don't have any experience with Divi's, but I've had an early model Deauville (similar age to yours) in the past and they're known for having dodgy fuel pumps.  The symptoms aren't always obvious . . . 

 . . . what's s'posed to happen is that the pump drains the tank to empty.  But the Deauvilles will still work when the pump gives up; when that happens, the system behaves as though it's gravity fed. 

That works fine, right up to the point where the pipework from tank-to-pump-to-carbs is higher than the level of the remaining fuel in the tank (the rear of the tank sits comparatively low).  At that point, the bike dies despite there being several litres of fuel left because there's no way of forcing the remaining fuel to the carbs.

Check the obvious stuff first, but like I say, this might just something you add to the list . . .

The fuel tap on the bottom of the tank is lower than the carbs, hence the fuel pump. It does make you wonder if the fuel pump is simply not working and the fuel in the tank above the carbs is getting through until the fuel level is at the carb float height.
Tom
'73 CB550 with CB500 engine café racer
'62 CB77 Sprinter
'70 CD175
'78 CB550 with sidecar
'80 Z50R
And a load of old Yamaha 1100's

Offline gtmdriver

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Re: Yamaha XJ 900s Diversion 1998
« Reply #5 on: January 28, 2020, 06:57:06 PM »
I have a 1996 900 Diversion (with a rare working gauge) and I start to look for a garage after about 150/160 miles.

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #6 on: February 01, 2020, 07:40:32 AM »
Than you all for your responses so far.

Yesterday I filled the tank and rode home the mile and half from the garage. I drained the full tank into a clean container and got 22.8 litres. I removed the tank and dismantled the sender unit and the fuel tap. This allowed me to about another 0.5 litre of fuel out. So, tank had about 23 litres in.

I could see nothing that would interfere with the flow of fuel out of the tank and confirmed the breather was clear.

A new Division fuel pump is £500 so I was thinking of fitting one of these :

https://www.ebay.co.uk/itm/Facet-Posi-Flow-Electronic-8mm-Union-Fuel-Pump-Kit-20-Gallon-Hour-1-5-4-0-Psi/361079202256?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

My only concern is that this style of pump continues to run even when the bowls are full so would be maintaining pressure against the closed float valves. There is a non return valve inbuilt to the pump, so when the pump is off, the tank couldn’t drain back through the carbs if one of the float valves was passing.

Anybody used one of these pumps and have any experiences, good or bad?
2015 Triumph Bonneville T100 Newchurch

Offline K2-K6

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Re: Yamaha XJ 900s Diversion 1998
« Reply #7 on: February 01, 2020, 11:21:33 AM »
Facet are a good reliable make which shouldn't give you any problems from that perspective.

It appears to be specified to feed float bowl carbs which should suit your application.  As to the constant running,  I've ordinarily used SU type that halt when flow is stopped by float valve so unsure of the implications of continuous running. But they must be able to cope (thinking heat buildup)  as they are effectively direct replacement for SU type.

Presumably they've effectively got a internal arrangement that allows a leak by when they meet their maximum pressure else they wouldn't have that 4psi max spec,  but I've never taken one apart.  A bit rambling,  but just talking it through out loud  :)

Looks like it'd do the job and they seem to be using them on cars that would see gentle running use of around 30-40 mpg-ish,  is that anywhere near your usage? But would cope with full on rate down into the lower 20s,  it would seem to have the range to cope with your intended use.

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #8 on: February 01, 2020, 10:18:46 PM »
They’re sales bumph says they’re designed to run constantly, so that shouldn’t be an issue for the pump. It’s the constant pressure on the float valves that concerns me but since asking on here, I’ve read an article on a Yamaha forum, where somebody is recommending a facet pump for a 600 Diversion, so on that basis I’m going to go ahead and fit one. Suck it and see.

I’ll let you know how I get on.
2015 Triumph Bonneville T100 Newchurch

Offline the-chauffeur

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Re: Yamaha XJ 900s Diversion 1998
« Reply #9 on: February 02, 2020, 02:16:19 AM »
So as I mentioned, I had the same issue on the Deauville, and there's a whole load of Deauville resources out there explaining how folks have dealt with the problem.  Looking at eBay parts, I'm fairly sure the Divi's fuel pump is pretty much identical to the Deau's, so the fixes should work pretty much the same for both.

If you haven't already bought anything, your first option might be to repair the pump you've got.  Wemoto sell a points repair kit for your original fuel pump - that's generally the bit that goes wrong.  It's pretty simple to replace; pull the black cap off the pump, unscrew some bits and replace for less than twenty quid. 

Trouble is, those points can fail again over time because just like the originals, the current that arcs across them is too powerful over the long term (although if you're still on your first fuel pump/relay, it might be a good while before they go again).  The fix for that is to solder a diode into the points circuit as outlined on this page (I know it talks about the Hawk, but all the pumps are the same basic design).  Sadly, the embedded links on that site have long since gone, but post some pictures here and folks should be able to tell you how to do the mod.

Alternatively, there are a couple of different write-ups on solid state fuel pumps - choose from this one or this one.  I'm sure there are more, and I'd guess if you go hunting you'll probably find something similar from Divi owner groups.

Hope that helps.

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #10 on: February 02, 2020, 08:47:29 AM »
Hi, very interesting. I did the point repair a few months ago, the pump is working but it’s not emptying the tank, so I have reduced range.

I’ve already got a Facet Posi-Flow pump, 60104, that one of your useful articles refers to, so I’m going to fit that this morning. I’ll do a temporary trial fit, then if successful, fabricate a suitable bracket.

Due to the facets inlet and outlet being on opposite ends, it will be awkward to fit in place of the original pump, which has in and out on the same end. I think the best place for the new pump will be under the tank where the inline filter is. This should give me a much simpler fuel line run.

Thanks again to everyone for their input, much appreciated.
2015 Triumph Bonneville T100 Newchurch

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #11 on: February 02, 2020, 03:55:46 PM »
Well I bit the bullet this morning and fitted the Facet Posi flo pump. I removed the existing inline fuel filter and fitted the Facet pump complete with its own inline filter. Now on test.
Thank you all for your input.
2015 Triumph Bonneville T100 Newchurch

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #12 on: February 02, 2020, 03:56:35 PM »
In line filter removed
2015 Triumph Bonneville T100 Newchurch

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #13 on: February 02, 2020, 03:59:12 PM »
Pump and new inline filter put in its place
2015 Triumph Bonneville T100 Newchurch

Offline jon stead

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Re: Yamaha XJ 900s Diversion 1998
« Reply #14 on: February 02, 2020, 04:00:24 PM »
Temporary cable ties, on test now.

Thank you all for your input
2015 Triumph Bonneville T100 Newchurch

 

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