piaggio zip 50 2t problems

i have a piaggio zip 50 cat 2t completley standard when i full throttle it goes to cut out like its flooding,it starts first time and is fine on quarter to half throttle,only on full ive cleaned the carb,checked for leaks,changed the air filter,any body got any ideas thanks

 

have you tried a new spark plug ? also worth checking your rollers for wear/flats

 

no i havent tried a new plug ive cleaned it but it looks new

 

when was the last time it was changed ?

a brand new plug can be carbon fouled within minutes and misfiring/playing up, if the mixture is too rich...

 

that would be the same initial advice I would give, always eliminate the plug as a, it's cheap, b, it's good to have a spare.

next stop is to open the variator, and examine the rollers, for the reasons stated above.


Dave has posted while I wrote this, listen to what he has to say.

 

i have replaced the plug and checked the variator and all seems fine no flatspots on the rollers,it seems like its over fueling as the plug is very wet petrol as when u full throtle it goes to cut out then picks up a abit then cuts and so on maybe it s the carb or needle or something

 

check the petrol tap isnt stuck on, its easy to check takes 2 mins...

theres 2 pipes attatched to the vacuum fuel tap, 1 is the fuel pipe and the other is vacuum.

if you suck on the vac pipe, fuel should come out of the fuel pipe, when you stop sucking, fuel should stop coming out... simples

if the fuel tap is stuck on, the diaphragm is probably goosed inside, a new tap as a whole unit will be required...

if the tap is ok, the next port of call is the carb, check the float shut off valve isnt sticking inside

 

as soon as i take the the fuel pipe off petrol poors out wether im sucking on the vacuum pipe or not lol is that normal? thanks

 

sounds like you need a new petrol tap then

 

changed the fuel tap today as the old one was defo faulty havent took it for a run yet tho hopeing its solved the problem thanks for the help will update later.

 

the fuel tap has not solved the problem its still doing the same so im thinking its the carb or choke even tho ive cleaned it and cant see anything up with it,does any1 no which noth on the needle the slide goes thanks

 

What size mainjet are you running?

 

its a 56 i think

 

Double check, 56 is correct for a stock derestricted piaggio engine with cat removed. If the cat is still installed then downjet to a 53 or remove the cat converter.

The problem you've discribed sounds like over fueling at full throttle, IE: mainjet slightly too big.

 

all the pipe work is still there for the cat as its still got the standard exhaust on it so i presume its still got the cat on it ill try changing the jet to a 53

 

Doing a "plug chop" would tell you alot too. Take the bike to a long road where you can hold full throttle for half a mile or so, bring a spark plug spanner with you so you can get an accurate test at the road side. Do the full throttle run, then immedietly pull over and switch off the engine then check the plug colour.

If its running rich at full throttle, the plug will be a black colour and may be oiley/wet.
If its running lean, the plug will be white/gray.
The colour your looking for is a light brown (coffee, chocolate colour)

 

i cant full throttle it goes to cut out after half throttle like its over fueling

 

Oh well in that case it sounds more like a transmission related problem, or the engine is running exreamly lean and cannot rev. Leave the 56jet in, it shouldnt cause the problem you just said. But still do a plug chop as it can tell you alot about how your engine is running.

Check the inlet manifold for splits, if its getting old and cracking like an old tyre then replace it.
Also check the airbox rubber for splits, ensure its installed on the airbox correctly, and tight on the carb. Check the filter element is in its correct place and just cancel out any possible air leaks.

The cat should run from the exhaust into a little box, then back into the airbox. If its been disconnected you could try plugging the hole in the airbox, or upjetting to suit (although a 56jet is the correct size for a de-catted standard piaggio).

The other thing to check is the roller weights, they should be 19mm x 15mm & weight should be around 7 grams, although after de-restriction 6.5gram rollers or lighter should be fitted. So thats size and weight to check, then check the overall condition of the weights, worn out rollers will have "flat spots", inspect them under a bright light to check for wear & flat spots.

 

if the rollers were worn would it stop the engine from reving up?

as soon as u full throtle it goes to cut ,then goes.then cut and so on,if u full throttle straight away it will go to like tick over its like when u run out of fuel it makes that noise then dies lol cant really describe it that well.

 

when you run out of fuel, your engine is starved of fuel (too lean) so if it makes that noise, its too lean....so check for any air leaks, including splits in any vac pipes, if that checks out ok you need to be investigating the carb and fuel delivery

if everything checks out ok with the fuel side of things, ignition is the next thing, as lack of ignition can make the same noise as running lean too... its all quite easy stuff if you work methodically