Speedfight4 Ice Blade 50cc 2T LC-Tune

Good Afternoon,
Complete newbie to this forum and owning a scooter.

I have recently fitted 6.2g rollers, removed the variator washer and fitted a Leo Vince TT exhaust (restrictor removed).
The accel has improved massively but the top end doesn't seem to have increased much.

I am struggling to find info on CDI's on the speedfight3/4's has anyone got any suggestions to improve top end, is there a CDI limiting revs etc?
I am obviously not expecting miracles and I do realise it is only a 50cc but reading some of your posts makes me wonder if I am missing something obvious.

70cc & carb upgrades can wait for now.

Thanks
Lewis

 

possible the pug is limiting rpm via the cdi , a dealer could unlock it .

you did upjet the carb when you added the new exhaust system , you could find the power less on top end due to fuel starvation if you have not adjusted the main jet in carb to allow more fuel into the motor , at high rpm you need more fuel than the stock setup would have delivered that in turn produces ecessive heat and has an adverse effect on top end running and overheating problems

 

Thanks for advice.

I will look at the upjet procedure, I haven't done that yet, any ideas what size/type are currently fitted and what size I should go to?

I have read the sticky attached and it seems really good but info for the SF4 is hard to find

Thanks again

 

the sf4 is still a relativly new scoot its been upgraded from the older sf1-2 we used to know well, the 3-4 had changes to them body and running wise to keep up with youngsters likes and the rules and regs laid out by eu laws .

to start upjetting you really need to find out what main jet is already fitted, to do this means removing the carb and then taking of the carbs float bowl, once removed you have entry to the float compartment and where the main jet and pilot jets are. the main jet is a brass like screw with a hole through its enter its usually the first one you cometo and is on a longish stem protruding into the carb bowl. on the side / top of this jet with be a number stamped into it thats the jet size.

to resize you would take the mainjets size ie 56 and add a 10% extra to it so the new jet size would be somewhere around 66 in size, problem here is its just a rough guess so its betetr to grab a few jet sizes or a jet kit, say from size 72 down to size 60 . this way you have jetting to cover just over the 10% rule and just below the 10% rule, from here its just popping in a jet and doing a test run to see how everything feels , throttle response - pickup on speed and overall top speed running, if it feels a little off you would then go up a jet size or down a jet size until you had a good feel.

from here it would be plug chopping , where you run the scoot at top speed then turn off the ignition and coast to a stop without engine running, you then remove the sparkplug and check its colouring this colouring on the sparkplug tells you the state the engine was running like at that very moment you chopped the ignition off.

white plug tip = lean mixture setting that says maybe need to go up a jet size again
black plug tip = running to rich and to much fuel so would mean a lower jet size could be needed
chocolate brown tip = a good balance on the fuel burn its good meaning its running a fraction rich as is always advised and the burn is clean

 

Thanks for the in depth advice Tamiyacowboy.

I'll have a look at that and get back to you with the results