Starstream 50cc engine options?

[bjhart]

I have bought my son a starstream for us to restore together ready for his 16th, which is about 2 1/2 years away.

It came with a 3 speed 100cc engine and I think I have everything to convert to 50cc, although reading about the 50cc engine I gather they are very under powered to the point of being dangerous. I have also bought some bare 4 speed 125 casings and have started to accumulate the parts needed for that engine although I still need quite a few more I think.

Question 1. What are the options for a 50cc engine, is it possible to build something based around the 4 speed engine to give the extra gear? Also this would then give the option to return to 125 when the time comes.

Question 2. What tweaks can be made to the 50 cc engine to give it a little more umph, tuning, carb, exhaust etc without compromising reliability too much.

Question 3. As said I have a whole 3 speed engine (presumed in running order) a bare 4 speed casing and a whole load of engine spares ( gear parts, cranks etc) can anyone tell me what parts I would need to use to build a 50cc engine based on either engine casing (3 and 4 speed) and how to identify the parts.

Lots of questions I know, any help appreciated.

[Wack]

Probably your best bet would be the Casa 75 cc kit for the 50 motor.

[bjhart]

It needs to be 50cc for a 16 yr old learner, I was thinking very mild tuned 50cc cylinder to allow it to pull the 125 gearbox and larger wheels

Thanks for the input though

[Wack]

I'd very much doubt a 50 would pull the 125 gears. I messed about with a Lui 50 and managed to get 40 mph out of it but the 1st gear is painfully low and made pulling away from the lights scary with traffic behind. I understand you want to be legal but a 50 is more dangerous on our roads than having something that can at least keep up with 30 mph traffic. Think back to the Vespa 50 Special, 28 mph tops but in a day when there was a lot less traffic and hazards on the roads.