Anyone know anything about scooters?

Got my Speedfight 100 back together today with a new fully charged battery.

I have got spark, and I *think* I have compression, but with such a
small engine its hard to tell.

When I turn the bike over it cranks and cranks but won't fire. I have
pulled the fuel line out and no fuel comes out when the engine turns
over, but if I suck the vacuum tube it does.

So for some reason it not generating enough vacuum to let the fuel flow???

When the bike turns over and I put my hand to the exhaust I can feel the
air coming out, but very little into the air intake itself.

I did have the head off the bike, and didnt replace the gasket, could
this be enough to stop the bike sucking the fuel tap open?

--
Gavin.

For the road: GSXR600K1
For the track: <gone>
Current project: Peugeot Speedfight 2
For everything else: Citroën Berlingo

MSN:
Twitter: http://twitter.com/gavin_wilby
Blog: http://www.stoof.co.uk

 

Who knows, chuck a gallon of petrol over it and get rid of it.

 

Why didn't you replace the head gasket - or do you mean that you re-used the
old one? How long has it been since it was last used? Could be the carb
being gummed up with old fuel if it has stood for a while. Could be a
sticking float needle, preventing fuel getting into the carb. Does it have
an immobiliser - if so it might have malfunctioned. Anyway - get some
"Start Ya Bastard" or Holts "Cold Start" and spray some into the air intake
and see if it fires with some assistance.

 

You could ask in the Spanish group. They're scooter-tolerant.

 

If it's a stroker then any suction will come from the crankcase. If
you haven't disturbed the cylinder base gasket then all should be OK
in the intake side. Did you remove the carb?

Disregard above if four-stroke.

Where on the air intake are you measuring? dorectly on the carb mouth
or on the airbox?

 

Re-used the original.

How long has it been since it was last used? Could be the carb

It was running, but I drained all the fuel from it as soon as I started
work on it, so its effectivly dry.

Could be a

Fuel isnt getting that far, as above, the vacuum bit isnt opening the
fuel tap.

Does it have

It does, but I get a spark, if it was the immobiliser then surely that
wouldnt happen?

Anyway - get some

--
Gavin.

For the road: GSXR600K1
For the track: <gone>
Current project: Peugeot Speedfight 2
For everything else: Citroën Berlingo

MSN:
Twitter: http://twitter.com/gavin_wilby
Blog: http://www.stoof.co.uk

 

It is a two stroke yes. I had the entire head off the engine down to the
case. The heads in two parts, a lower steel bit with an alloy top that
the spark goes into. There is a metal gasket between the two and a
normal one between that and the engine case.

I have a feeling that it might be that not replacing the gaskets with
new was a fucking stupid thing to do.

I assume that if there is any type of airleak, then it will **** up the
suction/ compression?

On the airbox, which is a twat to get on/ off.

I had the carb off, but didnt dissassemble, it was just to give a clean
and replace the hose clips that connect it.

--
Gavin.

For the road: GSXR600K1
For the track: <gone>
Current project: Peugeot Speedfight 2
For everything else: Citroën Berlingo

MSN:
Twitter: http://twitter.com/gavin_wilby
Blog: http://www.stoof.co.uk

 

Um, I dunno if the Speedfight has the same system, but Boxerboy of this
parish had no end of probems with the fuel flow on his son's Malaguti
scooter.

There was a mechanical fuel pump, operated (believe it or not) by the
swinging arm. The carb and pipes contained enough fuel to let it run for
a surprising amount of time, but after that, the only way to feed fuel
was to bounce on the seat.

In normal operation, the constant movement of the swinging arm was
enough to ensure permanent fuel flow.

 

There is a fuel tap on the bottom of the fuel tank with two hoses that
come out of it. One supplies the fuel to the carb, one creates a vacuum
that opens a little diaphram (I guess) in the fuel tap that lets the
fuel flow.

The engine isnt creating that vacuum for some reason. I know it works
cos if you suck the vacuum tube, the fuel pours out the end of the other.

yes, I have tried swapping them round


--
Gavin.

For the road: GSXR600K1
For the track: <gone>
Current project: Peugeot Speedfight 2
For everything else: Citroën Berlingo

MSN:
Twitter: http://twitter.com/gavin_wilby
Blog: http://www.stoof.co.uk

 

The 'lower steel bit' would be the barrel.

Probably. Did the gaskets stay in one piece?

I be a little surprised if it was leaking so much that it couldn't get
enough vacuum for the fuel. If it won't fire on EZstart then I'd deffo
get some new gaskets and get 'em in pronto.

 

Good grief that would be a bugger to diagnose if you didn't know about
it. I wonder if it applies to Moto Guzzi V11 sports?

 

Im no mechanic

The best I can remember is "sort of".

Would I feel it if I put a hand round the head during cranking?

--
Gavin.

For the road: GSXR600K1
For the track: <gone>
Current project: Peugeot Speedfight 2
For everything else: Citroën Berlingo

MSN:
Twitter: http://twitter.com/gavin_wilby
Blog: http://www.stoof.co.uk

 

Have you tried starting it at the same time as you're sucking it off?


--
Beav

VN 750
Zed 1000
OMF# 19

 

Is it two-stroke? My exhaust got coked up and had to be opened up de-
coked and re-welded. Same symptoms.