how do you get more RPM

[aeroxage]

how do you get more RPM out of your scoot?
and what are the factors behind it?

 

[StepVino]

how do you get more RPM out of your scoot?
and what are the factors behind it?

I found that lower compression and leaner mixtures help, also
shortening the header. Example on my ported 50cc Yamaha Vino:

135 lbs compression 125 main jet : 11.4k rpm (few seconds then overheats)
100 lbs compression 120 main jet: 11.8k
100lbs compression, 120main jet, Next R w/20mm shorter header:12.5k rpm

However, top speed was the same in last two cases, 57-58mph.

 

[spectroplasm]

nice to know this information

 

[aeroxage]

I found that lower compression and leaner mixtures help, also
shortening the header. Example on my ported 50cc Yamaha Vino:

135 lbs compression 125 main jet : 11.4k rpm (few seconds then overheats)
100 lbs compression 120 main jet: 11.8k
100lbs compression, 120main jet, Next R w/20mm shorter header:12.5k rpm

However, top speed was the same in last two cases, 57-58mph.

Thanks heaps for your reply,
what did you mean by "shortening the header"
also how do you lower the compression.
and did you port your piston yourself.

i have a stock 50cc block. + 17.5 carb with 125 main jet, power filter, yasuni R, sport variator, delta clutch. i get 85-87 km/h at 9000 rpm.
9000 rpm is the most i get.
do you think it's easier to just buy a malossi or polini 50 or 68 kit instead.

cheers Step

 

[tiba_karotsu]

if you want the easy way out buy a 70cc sport kit but if you want the hard path but the most rewarding you can tune the stock cilinder to perform as the same level as a sport or race cilinder.