Drain carbs if sat for a week?

utopia · 28-11-2018, 02:27 PM

Yep, that all sounds reasonable to me.
And leads me to think that, next time the float bowls are drained, it might be worth blowing back down the vent tubes to check that they're clear.
I'm thinking that this wouldn't be possible when the bowls are full as there would be no vent path, but I would think that there should be no such problem if the bowls are empty and the drain valves left cracked open while blowing.

Mind you, if the vents are blocked then presumably the bike would be running poorly and rather lean under "normal" conditions (due to inadequate filling of the bowls), and this appears not to be the case.

I'm inclined to plump for the "there is no problem" option.
Then again, cleaning out the float bowls and overhauling the fuel pump wouldn't be a bad ploy, particularly in an older bike.
Maybe the sluggish starting is exaggerated by a "lazy" fuel pump which takes a little longer to refill the bowls.
But either way, I would have thought that most carbed monsters must be due for a fuel pump overhaul by now, particularly given the ethanol situation.
That said, my 18yr old, 26k miles 750 is still seemingly fine on its original, unserviced vac fuel pump.

If needed, Allens Performance apparently supply rebuild kits for the pump.

28-11-2018, 02:27 PM	#19
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	Yep, that all sounds reasonable to me. And leads me to think that, next time the float bowls are drained, it might be worth blowing back down the vent tubes to check that they're clear. I'm thinking that this wouldn't be possible when the bowls are full as there would be no vent path, but I would think that there should be no such problem if the bowls are empty and the drain valves left cracked open while blowing. Mind you, if the vents are blocked then presumably the bike would be running poorly and rather lean under "normal" conditions (due to inadequate filling of the bowls), and this appears not to be the case. I'm inclined to plump for the "there is no problem" option. Then again, cleaning out the float bowls and overhauling the fuel pump wouldn't be a bad ploy, particularly in an older bike. Maybe the sluggish starting is exaggerated by a "lazy" fuel pump which takes a little longer to refill the bowls. But either way, I would have thought that most carbed monsters must be due for a fuel pump overhaul by now, particularly given the ethanol situation. That said, my 18yr old, 26k miles 750 is still seemingly fine on its original, unserviced vac fuel pump. If needed, Allens Performance apparently supply rebuild kits for the pump.