CVT + PULLEY GEARING  By  vintagepgogod123 (Read 1,038 times)

Usually a performance clutch will let the engine wind up before engaging to give you more of a neck snap when engaging but will not enhance hill climbing very much unless you put in a stronger contra spring. Putting in sliders and keeping the stock clutch works better for me and is much cheaper too. I find a jerky clutch irritating after a while in city traffic. At almost 30,000 miles the clutch on my Piaggio powered Sport City is nowhere near requiring replacement.

Get a good selection of carb jets ready for when you replace the muffler so you do not end up running lean from the change in back pressure and burn a hole in your piston top.

Hitting the red line means you're about to destroy the engine. You usually do not redline a near to 30 year old vintage ride. You really do not want a connecting rod coming loose and poking through the side of the block.

Depends on overall condition of the motor. An older 2 stroke needs some TLC to make it right. First is to ensure that the reed valves are clean without any pitting and that the carb is pristinely clean. Was there an oil injection system on that model or are you mixing oil with gas in the fuel tank at every fill up?

20 mph uphill may be a pretty good number for that bike if its an accurate reading. A 50cc can bog down to even less depending on the hill and the weight of the rider..

In general exhaust ports on the cylinder carbon up and need to be cleaned out as part of normal maintenance especially on the older 2 strokes or they get restricted causing overheating and poor performance. That is why many insist on only using the better 2 stroke oils to prevent carbon build up and extend the time between exhaust port cleanings.

Also verify that you have the correct size tires on the bike. 5 mph deviation at 30 is about normal not 20 mph and hitting engine redline indicated by the tachometer at a true 31 mph is not really right on a 50cc 2 stroke scooter and would be more likely at a true 45 or 50 mph albeit while going down hill. So really look closely at tire sizes, stuck sheaves not opening and closing fully, worn rollers, streatched belt, etc.

As for max that a 50cc 2 stroke can do my 1972 Motobecane Mobyette would do 40 tops and that was an old school pedal style moped. The 50cc Yamaha scooter of the day would do 45 mph top without redlining. A more modern Aprilia Ditec 50 2 stroke can top out at around 65 mph.

Yes worn or cracked reed valves can tick.

What are my reed options? Afo5e non metal or plastic stock plz.

bike was built in 87 but sat undriven in a garage for 18 of its undriven life if you spend all that time from valves sitting of corse their bad.

I can check them but i can guarentee % that there f'd off from their first high speed drive in 28 years as they probably only been changed 1 time if the reeds are not good then my timing is off why i say reed is because of tick when fully warmed up and splooge at low idle cold which means it has to be partially open on one of the sides.

Its got a new upgraded piston with rings, oil lines, gas lines,battery etc. I fixed it my self meaning not even PGO them selves remember crap about this scooter anymore.

Last is reeds, Cvt gearing, and rear brake pads.

"I tell ya everyone calls me a foo for it but i died for my scooter, i will go ham on anyone who f's with it.

"Ever seen a mother hawk f somone up over her babies? Ya well thats me..."

Satifaction is forever but the orginal piston was chipped, but after my findings it is probably "me" who f'd it over after rebuild.

Now that i know as much as i do now I am thinking I screwed up my timing at the pickup on the cvt side before the rebuild.





Ticking and dieseling after hot sounds like i should be pulling my cover and move the pickup back to the center.

I cant remember but i think it should be adjusted to the rear tire side undrilled but i cant remember if i drilled out both sides in that case i can take two fingers and pinch it til it feels even on both sides which will center it back.

I dont trust timing the pickup with the engine on, sounds like there is a chance that it can hit the magnetic point leading to snapping the pickup at the bump.

"Im knee deep in my scooter sloshing the fuel around like we been down since 87."


Piston is far from stock but is stock on newer models peep game 1984 aero nb50m rated at 40mm x 39.3 (dished low compression piston) now changed to 40mm x 39.2 (Dome top high compression)

The .1 is subtracted to clear the cylinder head change in characteristics in the past before tanked it only went 42kph now redlines at 50kph no butting or lag.

50kph last calculated at 31.63 mph gps on app on no cvt upgrade meaning my previous speed was less then probably 25mph

The dome increases top speed by a short circuit effect in combustion. The heat is evenly distributed between the pipes and cylinder excluding the tick factor caused by funky timing when fully at temp.



Making it preform has not been an issue i just want her ready for a rev limit delete and have it dyno tested to see its stress level @ red line.


If limiter is deleted im speculating 40-45mph on slight heavier rollers which will require me to own two cvts
Pulley systems stock rollers are currently well for pulling me and my giant bag of tools together we top at 210lbs max.

For speeding days just me and the bike thats only 154-156 lbs second cvt will contain lighter clutch with heavier rollers which pushes the ability to get up a hill lower round 20kph to 15kph speculation but on flat land pushes you further away from redline by rpm meaning the 10mm crank wrist pin will have to be tested to match the max rpm that can be handled.

(The enemy can talk but as of now this scooter is so old that it got lost in its time PGO Star been out since 87- if i am correct the problem with the 87 model is when you first build by pgo they kind of cloned honda (jug match is a Nb50 which means its cloned or based off.)

Was not until 1990 that jug style leaned more into yamaha jog style the 83 model of the cv50 riva/buluga matched as well to a tee but some models applied the reeds in the jugs them selves vs in the case siding.

#snaps finger#