Scooter problem

[Dutcho]

Ok guy's, hoping you can help me out.

I know it's not a car problem but here we go.

Don't know much about scooters and have been building a 50cc up for my son to ride.

I have replaced the bore and piston and the bike starts and generally runs ok.

The main problem, and reason for writting this thread, is that the bike struggles to 20 mph and has a tendency for the rev's to die out to nothing if kept at full bore for too long.


I have check carb and fueling as best I can.

Any ideas ?

 

[smirnoff_rules]

u might have to two stoke mixture wrong , try a tank of new petrol and mix lean first , thats where l would start m8

 

[smirnoff_rules]

u might have the two stroke mixture wrong , try a tank of new petrol and mix lean first , thats where l would start m8....sorry about that ,\well gets me more post lol

 

[Dutcho]

LOL... naughty.

Yeah I'll check it out put I think it's on a pump rather than self mix (well I know) and the plug doesnt seem to be oiling up. But hey worth a look

 

[pil196]

alot of scooters now have like an electronic choke on the carb it looks like
a little black unit with 2 leads running to it and this some times plays up
when the engine gets hot mostly on air cooled bikes just try removing this from the carb by extracting from the top of the carb held in by normaly
2 small screw type pins then fire up the bike and see if theres a diference
in the running if this makes it run better and revs out better then that should
be your problem

also make sure you have the right heat range of spark plug as some spark plugs tend to weeken there spark once thay reach over a certian temp

have you cleaned out the jets in the carb as it sounds like it could be
a fule problem follow the pipe from the tank and you should find a unit
that has 3 pipes on it one from the tank one going to the carb and another
going to the inlet between the the carb and the head in side that unit ther
is a small filter check the state of this filter also remove the pipe that gose to the inlet but only of the side where it fits on to the inlet and remove the fule
pipe but only off the carb end no fule should run out yet now just pick up
the pipe that you removed off the inlet and suck on it but only lightly
to see if you get a steady flow of fule


thats just a few things that might be worth a try m8

 

[Dutcho]

Yeah thanks for that. I'll have a play this weekend, weather permitting

 

[Kris]

Someone I know had a similar problem with their scooter after changing the exhaust.

It was down to the clutch springs and had to be changed.

I don't know if that applies to yours though because you haven't said a great deal about it.

Just throwing ideas out in the air.

 

[Dutcho]

Cheers, I'm gonna have a crack at de restricting it as well for him, it's basically the yamaha neo 50 engine so on with the trawl through the net to see where it's restricted

 

[Kris]

http://www.flexistentialist.org/archives/2003/10/28/derestricting_an.shtml

For an Aprilia but my mate used the same site when derestricting his Yamaha.

 

[Dutcho]

Cheers for that m8 Seems Im gonna have a busy weekend

I've already done the exhust, removed the cone, looks like I need to look at the carb and remove a washer

 

[JAMO13]

have you put the piston in the wright way it normaly has a arrow or a stroke on top of the piston, and have you but the gaskit in wright ,other wise it will suck in air through the head of the engine, and there is a way to test the piston with a compression tester which you can buy for a £10 in eny motor shop, and another thing have you tork the cylinder head bolts down properly

 

[Dutcho]

Yeah piston the correct way, built a few 2 strokers up