Variator Tuning For Low End Acceleration

Real Deal Neil /

May 20, 2020 10:59PM

Howdy y'all, looking for straight and simple advice on variator tuning. Yes I've researched these boards, but I'm looking for a straight answer that isn't trash talking, trolling, name calling, or bragging about how your 49cc scooter will wheelie with your 350lb body riding it all the way up to its 94mph gps verified top speed.

So I've been using the shutdown to fix up my Honda NU50 Urban Express. Motor is running great now, new carb, K&N filter, new top end with 70cc DR kit, boyesen reeds, and cleaned out stock exhaust. Sounds good, plug color is spot on, and topping out around 37mph or so with my 225lbs on it. New AX31 (the stock equivalent) belt. NOT the BX31 wider belt.

THE PROBLEM IS, this moped is still a dog right off the line up to about 15 or so when it really starts cooking. I DO NOT CARE ABOUT TOP SPEED!!!! I'm in Tennessee and the moped qualifies as a motorized bicycle meaning no plates, insurance, etc and I want to keep it that way. Law says 30mph top speed for motorized bicycles and apparently the motorcycle cops are aware of that fact and will bust your ass if they clock you faster so 30mph or so is all I want or need for downtown Nashville.

I have no real experience with bikes that don't use a clutch and shifted gears, but what I'm seeing is that swapping the variator weights, contra spring, etc might help, but it seems everybody is after top speed. Again, 30mph is plenty fast for my needs, I just need to get better low end torque.

Any Honda experts out there with experience-based guidance on what type combo of belt/spring/weights is the way to go for getting quicker off the line?

Many thanks in advance!!!

Re: Variator Tuning For Low End Acceleration

Chris . /

chrisleighty

May 20, 2020 11:49PM

start by removing every other stock weight, gets you to 39 grams total.

i was pretty happy with my stock urban plus malossi kit with 27 grams total, 6 Dr. pulley 4.5 gram sliders, but I weigh 160. I was using the stock carb/airbox/autochoke with a 90 or 92 jet, it's been a few years.

you can get 16 x 13 multi weight tuning sets on ebay to help dial in the right weight.

treatland sells a few bolt on clutches that take standard springs if you want to experiment with that, or drill out the arms on your stock clutch arms to lighten them.

Re: Variator Tuning For Low End Acceleration

Jack Rutherford /

churioz

May 21, 2020 12:50AM

Run a 9325 belt and experiment with variator weights from 30-39 grams given your stock exhaust. You can also add the shortest 14” rear tire you can find. Check your compression and if anywhere between 90-120, raise it 30 or so psi. Too rich a main jet will kill acceleration as will poor spark as will a poor seal between cylinder and exhaust. As will a carboned up exhaust. And of course check for rust and pitting on your pulleys in addition to oil or grease on pulleys or belt.

You also want the red clutch springs on a gy6 clutch. As far as contra, probably a yellow contra. I would think a heavier gauge contra would hurt acceleration. (edited)

Re: Variator Tuning For Low End Acceleration

Real Deal Neil /

nu50_victim OP

May 21, 2020 10:28PM

Thanks for the straightforward advice y'all. Just finished putting everything back together after taking out half the variator weights as suggested. If the weather stays dry tomorrow, will take it for a spin and go from there.

Re: Variator Tuning For Low End Acceleration

Real Deal Neil /

nu50_victim OP

May 22, 2020 11:59PM

Removing half the variator weights worked like a charm. Quick strong acceleration now, sounds great, tops out just above 30 on the flat and doesn't get overwhelmed by hills.

Thanks!

Re: Variator Tuning For Low End Acceleration

Tweaker trash /

carless

May 23, 2020 02:04AM

> Real Deal Neil Wrote:

> -------------------------------------------------------

> Removing half the variator weights worked like a charm. Quick strong

> acceleration now, sounds great, tops out just above 30 on the flat and

> doesn't get overwhelmed by hills.

>

> Thanks!

Now take a sharpie & make sure your variator is fully engaging! Useing too ligh of weights Will not have enough “force” to fully engage the variator Cheeks.

When the variator spins the weights become heavier. a 3g weight will become just as heavy as a 4g but at a higher rpm

G forces

Re: Variator Tuning For Low End Acceleration

Dirty30 Dillon /

hydra

May 23, 2020 09:40AM

> Barack Obama Wrote:

> -------------------------------------------------------

> > Real Deal Neil Wrote:

>

> > -------------------------------------------------------

>

> > Removing half the variator weights worked like a charm. Quick strong

>

> > acceleration now, sounds great, tops out just above 30 on the flat and

>

> > doesn't get overwhelmed by hills.

>

> >

>

> > Thanks!

>

> Now take a sharpie & make sure your variator is fully engaging! Useing

> too ligh of weights Will not have enough “force” to fully engage the

> variator Cheeks.

>

> When the variator spins the weights become heavier. a 3g weight will

> become just as heavy as a 4g but at a higher rpm

>

> G forces

The weights can not become heavier, that's plain physics man.

Re: Variator Tuning For Low End Acceleration

Tweaker trash /

carless

May 23, 2020 09:38PM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> > Barack Obama Wrote:

>

> > -------------------------------------------------------

>

> > > Real Deal Neil Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > Removing half the variator weights worked like a charm. Quick strong

>

> >

>

> > > acceleration now, sounds great, tops out just above 30 on the flat

> and

>

> >

>

> > > doesn't get overwhelmed by hills.

>

> >

>

> > >

>

> >

>

> > > Thanks!

>

> >

>

> > Now take a sharpie & make sure your variator is fully engaging! Useing

>

> > too ligh of weights Will not have enough “force” to fully engage the

>

> > variator Cheeks.

>

> >

>

> > When the variator spins the weights become heavier. a 3g weight will

>

> > become just as heavy as a 4g but at a higher rpm

>

> >

>

> > G forces

>

> The weights can not become heavier, that's plain physics man.

Centrifugal force cancels gravity.......Sorry

Re: Variator Tuning For Low End Acceleration

Dirty30 Dillon /

hydra

May 23, 2020 09:44PM

> Barack Obama Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > > Barack Obama Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > > Real Deal Neil Wrote:

>

> >

>

> > >

>

> >

>

> > > > -------------------------------------------------------

>

> >

>

> > >

>

> >

>

> > > > Removing half the variator weights worked like a charm. Quick

> strong

>

> >

>

> > >

>

> >

>

> > > > acceleration now, sounds great, tops out just above 30 on the flat

>

> > and

>

> >

>

> > >

>

> >

>

> > > > doesn't get overwhelmed by hills.

>

> >

>

> > >

>

> >

>

> > > >

>

> >

>

> > >

>

> >

>

> > > > Thanks!

>

> >

>

> > >

>

> >

>

> > > Now take a sharpie & make sure your variator is fully engaging!

> Useing

>

> >

>

> > > too ligh of weights Will not have enough “force” to fully engage the

>

> >

>

> > > variator Cheeks.

>

> >

>

> > >

>

> >

>

> > > When the variator spins the weights become heavier. a 3g weight

> will

>

> >

>

> > > become just as heavy as a 4g but at a higher rpm

>

> >

>

> > >

>

> >

>

> > > G forces

>

> >

>

> > The weights can not become heavier, that's plain physics man.

>

> Centrifugal force cancels gravity.......Sorry

Again, false.

Mass can only be increased by adding physical mass.

No one would say "when your fire a bullet, that bullet weighs over XXX lbs." The bullet weighs the same, in the cartridge and in the air. Just like weights.

Re: Variator Tuning For Low End Acceleration

Tweaker trash /

carless

May 23, 2020 10:05PM

A bullet going in a straight line is not have centrifugal force act on it (edited)

Re: Variator Tuning For Low End Acceleration

Dirty30 Dillon /

hydra

May 23, 2020 10:38PM

> Barack Obama Wrote:

> -------------------------------------------------------

> A bullet going in a straight line is not have centrifugal force act on

> it

Whether it's rotation or propulsion, physics are physics dude. Whether or not gravity is on play, it still has the same mass no matter what type of force is exerted on it.

Re: Variator Tuning For Low End Acceleration

Tweaker trash /

carless

May 23, 2020 10:55PM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> > Barack Obama Wrote:

>

> > -------------------------------------------------------

>

> > A bullet going in a straight line is not have centrifugal force act on

>

> > it

>

> Whether it's rotation or propulsion, physics are physics dude. Whether

> or not gravity is on play, it still has the same mass no matter what

> type of force is exerted on it.

Umm okay......

Re: Variator Tuning For Low End Acceleration

Ike Pipe /

1ke

May 25, 2020 12:42AM

Mass and weight are not synonymous.

Mass is a measure of the amount of matter in a given volume. Weight is a measure of gravity pulling on a body.

Example : person weighing 100lbs on earth travels to the moon and there weighs 20 lbs. Same mass, different weight.

Re: Variator Tuning For Low End Acceleration

Dirty30 Dillon /

hydra

May 25, 2020 01:28AM

> Ike Pipe Wrote:

> -------------------------------------------------------

> Mass and weight are not synonymous.

>

> Mass is a measure of the amount of matter in a given volume. Weight is a

> measure of gravity pulling on a body.

>

> Example : person weighing 100lbs on earth travels to the moon and there

> weighs 20 lbs. Same mass, different weight.

Grams are both a measurement of weight and mass. A 6 gram weight, is still 6 grams in a variator, but the force it is exerting is greater thanks to centrifugal force. It still weighs 6 grams, spinning or not.

Re: Variator Tuning For Low End Acceleration

Ike Pipe /

1ke

May 25, 2020 04:36PM

https://www.nyu.edu/pages/mathmol/textbook/weightvmass.html

I agree that a 6g weight has the same mass when sitting on a bench as it does when spinning in a variator.

But gravity is a force that varies as the density of materials vary. As in, gravity is not constant our planet.

Centrifugal force therefore is also variable. Slow speeds impart less force on your weights than higher speeds, which is a change in weight, but not a change in mass.

Science!

Re: Variator Tuning For Low End Acceleration

P D /

pdcomm

May 25, 2020 05:00PM

Maybe some of you guys are confusing pressure with weight . ;)

Re: Variator Tuning For Low End Acceleration

Tweaker trash /

carless

May 25, 2020 07:09PM

> P D Wrote:

> -------------------------------------------------------

> Maybe some of you guys are confusing pressure with weight . ;)

No I’m just confused lol

I probably should of just keep my mouth shut

MOPED ARMY

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