vacuum pump

[snakey]

has anyone had trouble with the vacuum pump on the monster? - the symptoms are leading me to the conclusion that this is at fault, a couple of times as i have first pulled away the engine has almost locked up and then run and the other day just "died" in the center of town as if i had run out of fuel (there is some in the tank , shell v-power and octane booster for the cold weather) and the engine turns over on the button but will not fire, the RAC came and checked it over and took the fuel line off from the tank to the filter and with the ignition on it was pumping fuel so that is ok . any thoughts would be appreciated


Pete

[lcjohnny]

Hi Pete is it a carbed model or EFI?
Fuel pump on my carbed model barely puts out any pressure at all.

There is also a vacuum tap - which is more of a problem

JonG

[dunlop0_1]

The vacuum pump (bolted under and in front of the tank hinge) can be bypassed thus eliminating any problem with it. They cost about £26, check all the vacuum hoses are clear and leak free first.

[snakey]

The pump under the tank seems to be working ok as it operated when the bike was turned over, the one that i was wondering about is the larger hexagonal one bolted to the frame , just in front of the clutch housing.

pete.

[lcjohnny]

The vacuum fuel tap is bolted in front of and below the tank hinge

The fuel pump is on the right hand side in front of the vertical cylinder.

Both are driven by vacuum one from each manifold.

Of course that is on a carbed 900 - the EFI ones will have a more powerful pump and I don't know if they have a vacuum tap.

Jon G

[stevie babe]

I had a problem just like it last year turned out to be the fuel filter, it was choked and could not supply enough for the demand of the engine.

[snakey]

thanks for the hints - will try the filter first then the fuel pump, when i get a chance , hopefully sometime over the weekend if it's not raining again.
Pete.

[lcjohnny]

Pete
sorry I should have come back on this. My 900 runs fine on fool throttle with very low pressure from the pump so I reckon it just acts as a lift pump for the bit of the tank that is lower then the float bowls.

Before suspecting the pump I would look for folded, twisted or collapsed fuel pipes or a blocked filter.

Then I would check the vacuum pipe that drives the pump for possible leaks.

To test the pump I would just undo the fuel feed pipe and spin the engine (plugs out to stop it running but leave them on the plug leads & earthed to avoid frying the coils) if the pump displaces fuel that should be enough,

If you need a rebuild I cannot find a kit for the single outlet pentagonal Mikuni pump however Allen's Performance parts http://www.allensperformance.co.uk/products-mik%20fuel%20pumps.html do a kit for a pentagonal twin outlet pump which may fir - it is no DF62-702.

Good luck Jon G:booze:

[snakey]

thanks - i will run through those tips as soon as i can get some time.
Pete.

[jerry]

Sounds classic fuel filter problem.

[snakey]

Sounds classic fuel filter problem.

You were right - ordered a new fuel filter, fiitted it this afternoon and found that the old one was nearly full of water, Thanks for the advice ( mental note - to change it in future!)

Pete:)

[Kato]

Solution to all vacuum fuel pump issues is quite simple junk it and fit an electric pump, I was advised by AK that OEM pumps from early R1 / R6 are just the job and can be had on fleebay for about £25.......hate to say it but he was right on both counts.

[Gamsa]

I've just fitted an electric fuel pump from a (carb) ZZR600 and it seems to have caused some problems. I have a carb overflow problem. I know the fuel levels were set at a sensible height, so I'm assuming the pump has put out enough pressure to bend the tab on the float valve. Has anyone else had problems with electric pumps? I could try an early R6 as recommended but would like to hear from people who have successfully lived with this modification, just to convince me that it's worth doing. I'm worried that these electric fuel pumps put out too much pressure for the carbs on the Monster. Thanks!