Gilera Stalker cuts out / bogs down after half throtttle.

I have just bought This moped and got a mobile mechanic to service it straight away. He checked lots of things and gave me a new spark plug. The main thing he found was that the oil pump wasn't on and the connected it back up to the throttle but the spring was broken so, the oil pump is always turned on even when the throttle isn't open.

The bike was working amazingly and was going 45mph up a slight hill.

The problem is that now I can only put it to half throttle, even then the bike stutters and has periods of acceleration then periods of non. When I go past half throttle it is like someone has put the brakes on a bit and it just comes to a stop, but it dose stutter a bit and has small half second periods of acceleration. It only dose 30mph which I don't mind. but going up hills it is terrible. as ever since I got the bike 3 days a ago it it wouldn't accelerate very much until i hit 10MPh the t would go like a rocket. but now because I cant get high revs because I cant go past half throttle I cant get up to 10mph on hills. Most of the time it feels like the brakes are being put on and taken off randomly.

It has a leo Vince TT exhaust which is districted this is why it will do 45. Two years ago it has a new cylinder kit and pistons to pass its MOT.

It is an 04 plate and has done 10600 miles/KM. I don't know which but the spedo is in km and the manual says km on it.

Any help / ideas appreciated.

 

could be to much oil i have a fully working oil pump if you want to buy one £15 collected or £20 posted

 

yer it was mate the extra oil really fucked it up. had to clean out the carb and fix the pump.

 

in iv got one thats done about 50 miles just sat here lol

 

well if you ever need a oil pump iv got one sat here its fresh done about 50 miles only problem is bleed screws rounded but it never effected me lol