Author Topic: Yamaha Diversion xj900s 1998  (Read 1223 times)

Offline jon stead

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Yamaha Diversion xj900s 1998
« on: September 21, 2019, 12:27:56 PM »
Need some advice good people.
Took the carbs off today to check out the sooting up on 1, 2 and 4. 3 was ok.
Took bowls off, everything looked immaculate, put bowls back on.
Took diaphragm covers off and found 1,2 and 4 needles separated from their respective carriers. Retrieved very small spring and washers and reassembled them. Has to be said the o ring that holds them in place had seen better days. I will need to replace them at some point.
Anyway, confident that I’d found my fault, put it all back together and now engine won’t start, just cranks over and over, with the low fuel light on. (Only on when starter button pressed). Tank is full, fuel tap is on. There’s no fuel coming out of the fuel bowl drains.
I took the supply pipe to carbs off, no fuel coming through.
Took fuel pump off, connected to 12v supply, pump runs ok
Pump is not getting 12 v supply, why? What have I missed whilst refitting the carbs?
2015 Triumph Bonneville T100 Newchurch

Offline jon stead

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Re: Yamaha Diversion xj900s 1998
« Reply #1 on: September 21, 2019, 02:10:26 PM »
Got the bike running. Rigged up temporary 12v supply to the fuel pump, filled carbs up, started bike, ran good. Stopped bike, started again just to see if it would. Stopped bike. Removed temp supply, reconnected to original supply, started engine. Ran it for 5 minutes without issue. Took it out for a ride and it was good. Thankfully.
Now I need to sort out the retention o rings for the needle assemblies

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2015 Triumph Bonneville T100 Newchurch

Offline Bryanj

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Re: Yamaha Diversion xj900s 1998
« Reply #2 on: September 21, 2019, 07:26:21 PM »
If they are anything like the 1200 wing the pump only get power when the engine runs, not on starter, so you have to gill carbs manualy or jumpstart the pump like you did

Offline jon stead

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Re: Yamaha Diversion xj900s 1998
« Reply #3 on: September 21, 2019, 07:28:37 PM »
That makes sense, thanks Bryan
2015 Triumph Bonneville T100 Newchurch

Offline gtmdriver

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Re: Yamaha Diversion xj900s 1998
« Reply #4 on: September 22, 2019, 08:17:11 AM »
As Bryan says!

As a safety feature on the Diversion (and most modern machines with an electric fuel pump) the pump only operates when the engine is turning so if you have completely emptied the carbs it can take a long time to fill them up again just turning the engine on the starter. By wiring an external supply to the pump you primed the system and filled the carbs so that it would fire up no problem and keep running properly. I have a 1996 900 Diversion.

Offline jon stead

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Re: Yamaha Diversion xj900s 1998
« Reply #5 on: September 22, 2019, 08:28:11 AM »
On mine there was no electrical supply whilst cranking the engine over. As Bryan says, the engine needs to be physically running before the fuel pump gets an electric supply.

I’m going to make a simple jump lead up and keep it under the seat in case I ever run out of fuel somewhere and need to fill the carbs before restarting the engine.
2015 Triumph Bonneville T100 Newchurch

Offline gtmdriver

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Re: Yamaha Diversion xj900s 1998
« Reply #6 on: September 22, 2019, 07:21:24 PM »
When I converted my VW beetle to efi I wired in a direct supply to the pump using a momentary push switch so that I could prime the system should I need to.

I'm surprised that there was no power to the pump on cranking. When I rebuilt my carbs I made sure I had a fully charged battery then just kept cranking the engine over till it fired (which it did).

Offline jon stead

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Re: Yamaha Diversion xj900s 1998
« Reply #7 on: September 23, 2019, 07:03:30 AM »
When I converted my VW beetle to efi I wired in a direct supply to the pump using a momentary push switch so that I could prime the system should I need to.

I'm surprised that there was no power to the pump on cranking. When I rebuilt my carbs I made sure I had a fully charged battery then just kept cranking the engine over till it fired (which it did).
Different system and set up I guess. I like the priming push button idea. Better yet, I'm just going to plan to not run out of fuel.

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Offline gtmdriver

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Re: Yamaha Diversion xj900s 1998
« Reply #8 on: September 23, 2019, 07:32:22 AM »
Sorry. I wasn't clear.

When I rebuilt my Diversion carbs the bike fired up after turning it over on the starter a few times so the fuel pump must have been energised during cranking.

 

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