mikecollum correctly told you that you are going to get different answers from different people, and this is true. I just don’t understand how you are supposed to choose from all this different answers.
I personally know people with polini177 doing thousands km with the kit set with too much advanced timing and didn’t have any problems. Others in this forum (our friend Stubsy) had endless problems, and the same for the Malossi 166. For the big PX200 kit is the same story.
If your choice is going to be a choice dictated from an average survey, without considering all the other variable and mistakes often made by the people mounting the kit (not enough squish band, not the correct timing, not the correct spark plug grade, not the correct carb set up, and last but not least cronic bad luck) then the kits that are more reliable are made from Pinasco. They are made from alu, they cool better, they are less powerful and so they give you a wider margin of set up error.
Or you could ring:
In England: Taffspeed, PM…
In Germany: Worb5, Scooter&Service…
get all the answer and then choose the one that convince you (for any reason) better. So again it is you, the one with the less experience choosing from the answers all given from people with much more experience! Strange…
And another strange thing is that accepting or following one shop advice is like saying they know better then people who made the kit? How come?
So you see that if you really should do it well you shouldn’t do anything at all?!
Or make a survey on this forum. At the end whatever choice you are going to do if you will end up having no problem you will say you did the right one but if you will have some problem you will say you made the wrong one.
…I would be more concerned doing the right set up though whatever kit you will end up using.
I just will not choose Malossi for its power band that I don’t think it is good for the use you are intending to and because it needs case porting and bigger carb to really work the way it is supposed to.
And for whatever reason even after a miracoulous correct engine set up , for some woo-doo or bad luck you will break the kit you will choose, yes it will be sad, but it is not a life, you could save for another one contributing to the lives of people working at Pinasco or Malossi or Polini, that it is not a bad thing, and you will live with less stress and with less space for nevrotic synthoms.
You could break your engine even if you don’t touch it.
You don’t know how many times I saw a standard barrel sizing for the breaking of the oil pump device…