84 aero 125cc problems running at top speed

[84_aero_red125]

Picked up a new toy and I did some research on it.
The research told me it will do about 55 to 60 mph but mine only does about 45 downhill.
Also, when I twist the throttle 100%, it will kind of bogs
down, so I need to run it at about 70% throttle to get it to run right.
Other than that, it starts right up and idles fine.
I've done nothing to the bike but put fresh gas and oil in it.
Please help.
Thank you ahead of time.

[84_aero_red125]

Read something about the rollers in the bearings or something, not sure how to go about changing them. Plus I'm running 93 octane. Don't know if that's ok or not.

['O'VerSe]

How does your plug look? Sounds like you need to play with your jetting a little more. Are you using an open filter?

[84_aero_red125]

What's an open filter? The bike is all stock. How do I play with the jetting? I'm pulling the plug in a few hours

[84_aero_red125]

How does your plug look? Sounds like you need to play with your jetting a little more. Are you using an open filter?

Do you mean like put new jets in? Or just clean them out.

[84_aero_red125]

Where's bear when ya need him lol

[motormike]

Not getting enough fuel.
It needs main jet cleaned.
Probably needs air filter too.

[84_aero_red125]

Great thank you. I'll start with that and a new plug.

['O'VerSe]

I apologize for getting back to you so late. +1 on what ^ motorbike said.

[84_aero_red125]

Yea I switched the plug and its the same if not worse

[84_aero_red125]

Does anyone know how to pack a muffler?

[motormike]

How many miles on your bike ?
The roller weights in the variator wear with use,
and will reduce top speed when worn.
You must remove the variator to inspect and replace rollers.
I say this, but believe you have fuel related problems as well...

[84_aero_red125]

A little over 5k it's definitly a fuel issue. When I'm full throttle it'll sputter trying to go faster but won't do more that 47

[motormike]

The best way to remedy your fuel problem is to start with tank, and clean or replace everything all the way to the engine case.
Fuel lines, screens, petcock lines, carburetor, reeds, gaskets, float needle, main jet metering needle, emulsion tube, by starter inlet,...trying to name the items of particular importance.

['O'VerSe]

Your scooter is stock from 1984 right? Unless it's a barn find. It's gonna have some wear. The piston and rings alone over time is enough to lose some top speed. Let alone a 32 year old crank. If your belt has never been changed. It's probably a couple millimeters less than new. Which will definetley effect speed. If it does have a variator. Your rollers are probably pretty flat by now. Also less speed. Tank and carb definetley need cleaning. Carb probably replaced. Not trying to discourage you at all. Not only do you have a rare model. But its potential is also high. I have two older bikes myself. With the right upgrades and some tlc I gauruntee your 125cc+ can get back up to speed.