Sluggish T5

Just got a mark 1 T5 and its really sluggish when pulling away.
It has a 110 main jet, simonini pipe.
i tried a 112 jet and it was worse.
ive noticed the air hose has slipped of. would this make a difference.
the plug looks ok.
it only does it when pulling away in 1st, it then picks up and is fine.


hello johnnyvespa,

any infiltration of air influence the carburation.
I don’t understand what part is the air hose. If it is the big tube attacched to the air box filter this shouldn’t make that much difference.

To me it seems you have a problem with the carburator iddle circuit.

Check the iddle jet.

First you have to make it sure that is not dirty.

If it is ok than try the iddle air screw open it 1/4 and see what you have. If the result is an improvement you can turn it a little more up to where it is ok. If it get worse put it back at the original position and close it 1/4. If it is better, this is the direction to go and you can turn it 1/8 more until you get it right.


[:’(] Think ive found the problem.
Took of the cylinder and one of the rings wasnt seated in its groove correctly, which has caused a 1.5mm groove down the barrel and over one of the ports,
Could this be the cause?
Or should i be lookin elsewhere?



this for sure is a problem.

put it back if the cilinder is not too damnaged , new ring, check the piston his condition and the way is mounted, try again and let us know.