some help with making my 50 (now 72cc) vino fast

[sarniascoot]

i started with cosmetic work and basic parts replacement (like crank shaft, carb etc) and now im in the whole phase of learning how to tune everything to make it run good, and this is where i need your help everyone! so far i have a V8 exhaust from autotech on e-bay and a set of 7G rollers coming. i have de-restricted my air box and i have a #85 main jet in my stock carb with a nice tan plug. right now with the v8 pipe and the 72cc BBK and everything else stock, the scooter accelerates pretty slowly. where should i go from here?

[90GTVert]

Sounds like it's time to work on the CVT. It would be helpful to have a tach. If you don't you should still be able to tell if it's revving too high or too low. If it's accelerating slowly and sounds like it's not revving very high, try lighter rollers. If it's accelerating slowly and revving high, try heavier rollers. If it bogs too much from a stop for the first 5-10MPH, you might want to try stiffer clutch springs. The whole key is that you have to get your CVT to operate within the engine's peak powerband. You could have a scooter making 15HP and it would be a dog if you never got near the RPM where it makes that power. With most sport stuff you'll probably be shooting for somewhere around 8,500-9,500RPM for best power. If the V8 pipe is the quiet street type, looks more like a header and a muffler than an expansion chamber, they usually like just a little less RPM. A lot of times tuning it for the best acceleration makes it a little too much for a good daily rider though, so you may compromise a little performance for lower cruise RPM and sometimes can get better max speeds that way.

[sarniascoot]

You sir, are a wealth of information! thanks for the pointers!

[jmkjr72]

my bet is 5.5 to 6.5 on the rollers and some medium clutch springs to let it rev a little

[sarniascoot]

some bad news. while running at about 65 Km/h for 5 mins, the back wheel locked up. it didnt stay locked, it locked for about 3 seconds, then i just jammed on the rear brake and skidded into a curb. my cvt case was VERY hot after. the engine stayed running the entire time so i've got no clue what could of caused this. i threw some oil in the gears but it only took 20ml if that.

[maccrew]

im not the best at all this but if the rear wheel locked up, first 2 things to look at i would think is wheel bearings and rear breaks.

[90GTVert]

Did you ride after that? If not, check the CVT. The belt can snap and get caught up the the rear pulley to lock the rear wheel. I've had that happen multiple times. Sometimes it lets go, sometimes it doesn't.

If it was just a fluke and it's still able to move on it's own, inspect the whole rear brake system for anything unusual.

[jmkjr72]

what do you mean it only took 20 ml
if you mean that it took 20 ml to come out the hole you are too full
the gear box only holds 110 cc and there is no hole to measure it by

[1quikvento]

jammin your sneaker between the rear wheel and frame only works on a bmx bike silly!!

[sarniascoot]

Jul 28, 2011 6:59:12 GMT -5 90GTVert said:

Did you ride after that? If not, check the CVT. The belt can snap and get caught up the the rear pulley to lock the rear wheel. I've had that happen multiple times. Sometimes it lets go, sometimes it doesn't.

If it was just a fluke and it's still able to move on it's own, inspect the whole rear brake system for anything unusual.

i inspected the entire cvt and its still a mystery why the wheel locked up. the brakes on the rear are pretty worn out. ill just have to ride on and see if it happens again.

[mccanic]

Jul 28, 2011 13:33:02 GMT -5 1quikvento said:

jammin your sneaker between the rear wheel and frame only works on a bmx bike silly!!

i love bmx! i have a fit str 2 its okay it weighs like 27pounds but the frame is bent, ive been riding to hard lol