pinking

[LI150]

On way home from work today my 210 malossi started pinking. The fuel was low so filled it up pinking stopped any idea why this would happen. This has done this once before and apart from this it runs well, done over a 1000 miles since built. Also timing is set at 17deg and main a 135 and plug colour good so no its none of these.

[drunkmunkey6969]

The fuel level in the tank has a massive effect on lean running on Vespas. It can be seen visually on a dyno, the difference between a low tank and a full tank is scary.

Never let your fuel level run low if you can help it.

[LI150]

Thanks for the reply and advice much appreciated...

[C*NTSPEED]

The fuel level in the tank has a massive effect on lean running on Vespas. It can be seen visually on a dyno, the difference between a low tank and a full tank is scary.

Never let your fuel level run low if you can help it.

but why?
why i ask is because im a bit thick and i dont see why it runs lean weather it has 5 liters of fuel in the tank or one liter
its mixed at 2% so mixture is constant so why does it matter if its a full tank half a tank or a spit?

[Knowledge]

Li150,

The way to ensure that your scooter always runs well (until it runs out of fuel), fit a fuel pump. You can chose between an electric one (if you have a battery) or a diaphram pump (e.g. Mikuni, Amal or Dell'orto).

[C*NTSPEED]

Because vespa's are gay (oops sorry ) when the fuel is low there isn't enough pressure to fill the float bowl fast enough and has the same effect as having an incorrectly set float height.

oh hark at her... there's nowt gayer than a fat mod pushing his lambretta cos he chose to ride the inferior model.....( we reallly do need a middle finger f@@k you smiliey)

[acko]

Yeah there's more than a few Lamgayers on here Joe.

[C*NTSPEED]

Because vespa's are gay (oops sorry ) when the fuel is low there isn't enough pressure to fill the float bowl fast enough and has the same effect as having an incorrectly set float height.

oh hark at her... there's nowt gayer than a fat mod pushing his lambretta cos he chose to ride the inferior model.....( we reallly do need a middle finger f@@k you smiliey)

LOL

Ill make one of them

good man

[LI150]

Li150,

The way to ensure that your scooter always runs well (until it runs out of fuel), fit a fuel pump. You can chose between an electric one (if you have a battery) or a diaphram pump (e.g. Mikuni, Amal or Dell'orto).

Now this is a good idea can you point me in the direction of a good one. I do have a battery so electric is fine...which type is best

Cheers tim

[Knowledge]

There are reliable pumps on most japanese four-strokes. The ones on the CBR600 seem good and come in a rubber mounted bracket which will need some fettling to fit, but should be OK. None of the electric ones I have come across are very small: think in the region of the size of an original Lambretta HT coil.

It is important with any of these installations to allow the excess pressure from either an electric pump or a diaphram pump to have an escape route back to the tank. See this sketch:



Note how the return pipe is fed into the top of the tank, so tha the volume of fuel in the return pipe acts as a header tank for the fuel system. However, this set-up requires you to have another hole inserted in your tank, which might not be convenient. This set-up avoids having to alter the tank:



.. and it uses two T-pieces in the fuel lines to achieve the same thing. However, the route of the return pipe must be long and high to achieve that "header tank" effect described above.

The diaphram pumps are simple. They utilise the pulses of the primary compression ratio to operate a diaphram pump. These are often fitted to auto-scooters as standard. However, you will need to drill and secure an additional pipe from the back of your crankcase to the diaphram pump. This might involve drilling and tapping the crankcase; a task you might prefer not to do if the engine is in one piece.

Good luck, and I hope this has been useful.