Phongeer Al-You-Minnie-Yum Pulley Sheave Intro

[Wheelman-111]

Greetings:

My one Scooter Indulgence for the Holiday season was this item from VT Cycles. I'd seen it around for $50 PLUS Shipping, and Steve was offering it for $45 Shipped - still on fEeBaY the last time I looked.
Nice satin-machined Al finish.

PGPulleyIn.jpg (60.07 KiB) Viewed 3513 times

That's my Kymco ZX pulley. The PG kickstart washer appears to match the shorter ZX kickstarter "castle" so no need to shim the belt cover out so far. The inside profile of the Kymco has a bit of a bump about an inch out from center. The PG is dead flat all the way to center.

I noted how high my belt rides on the Kymco. I always draw some radial Sharpie lines before I mount a belt, and they're completely erased. In fact, i think the blotchy black stuff near the toothy rim is where the belt kisses a little. My Variator is still the Giant Brand X 97mm so I'm using all the Overdrive for sure.

PGPulleyOut.jpg (64.41 KiB) Viewed 3513 times

I'm an idiot for installing it before I remembered to get a weight. The Steel one weighs 271.

PGPulleyWt271g.jpg (48.97 KiB) Viewed 3513 times

PG felt substantially lighter, even with its steel kickstarter toothed washer thingie. The heavy metal being close to center won't contribute much to rotating inertia. The belt-contact surface diameter is about the same at 91mm before the conical section flattens to the e-Start gear teeth. I measured 92 on the Kymco with a vernier caliper so all measures are imprecise AND inaccurate.

Bolted up without changing boss shims, and the belt seemed to ride pretty much exactly the same spot on the rear pulleys. Kickstarter didn't grind, and e-Start worked fine. With the boss shimmed out to ZX length, the pulley engages fully, but I don't think the splined washer even touches the crank splines.

A quick trip around the Casa Wheelman Compound revealed... Not much difference. I could convince myself that it grabbed Revs a little quicker than my pre-swap test ride with the steel Kymco, but the engine was warming up and who knows if it wasn't just that. Good launch and about the same RPM as before. I guess combined with a lightened magneto and tranny assembly, there might be some acceleration performance advantage. Then again, the heavier ZX rear pulley and belt is part of the "Flywheel" inertial assembly too, so it cancels some of the advantage.

However one real advantage is to people converting to ZX rear - the shorter kickstarter tower will mean less (or No?) cover shimming issue. It remains to be seen if it wears and holds up.

[eliteguy50]

Good write up. I have been wondering about this part for my af16. Have you had it on the highway yet?

[bradthreee]

Maybe since its lighter you can make up the weight in heavier rollers unless your belt is already at the top of the variator?

[eliteguy50]

The lighter sheave does not affect rollers. It will have an effect on the flywheel effect.

[SuprasNsprees]

the lightenend FW should allow the revs to come up faster , as there's less rotating mass to spin, correct ?

[Wheelman-111]

Greetings:

Lightening the rotating mass likely will result in quicker rev-up for sure. The thing about these scooters is that there's a whole lotta rotating mass. Starting on the right side, the magnetic flywheel, the crankshaft and its flywheels, the variator and outer pulley. The belt is always tightly gripped by the variator - held in tension by the rear pulley spring and pulley taper. Therefore the belt and REAR pulleys are also part of the "flywheel" effect. When the clutch engages, you can add the weight of the bell and axle and rear wheel, too. Weigh all that stuff in a pile sometime. Cutting 100 or 150 grams of weight from one sheave probably does not reduce that total mass by a very big fraction.

[eliteguy50]

Correct, but remember to multiply that tiny fraction by 9000 or whatever your rpm is when racing. That is what these are really for. A lighter you can cut more weight from the mag for a larger difference on a daily rider than the sheave. Do you run a tach on the current flash?

[Wheelman-111]

Greetings:

Yeah I have an older version of the Standard model of TinyTach. It's non-backlit, and refresh rate is like every hour (2 seconds...) so not a particularly useful tool to gauge the rate-of-climb in RPM. Flash seems to deliver best acceleration when the vario lets it spool up to 10K on WOT application. Highest RPM I've been able to see (TTach is a little hard to read and rheumy Wheelman Eyes at speed...) is about 10.5K. Speed at that RPM is a bit over 65. Flash 3.26's all-time best GPS still 69.9, but I have no idea at what RPM that occurred.

I've read someone's report that a lightened magwheel can fly apart, so for sure not going there for a Street Daily Rider.

[Bear45-70]

All the flywheel effect weight is to smooth out that 1 firing pulse per revolution. These thing vibrate bad enough with all that weight. Less will make the vibration worse. For racing, who cares about vibration, you don't ride that long, but for s street cruiser, vibration means tire out the rider sooner. Usually the butt first.

[Wheelman-111]

Greetings:

My longest scooter rides are 25 minutes. Monkey-Butt don't start for at least an hour, even on Paint-Shaker King Sportsters. The Elite doesn't even have the fuel capacity to challenge Wheel-Butt. Plus Plush perch saddle is like buttah.

The performance advantage for a racer is that the engine spools up and gets back to the powerband quicker coming out of the corners, when throttle is whacked open. The scooter with the lighter/quicker throttle response will squirt ahead every time. The Al pulley alone might give this advantage, but it won't be a game-changer.

In any case, a lighter rotating mass will likely have NO effect on peak speed, perhaps just a little on how quickly the bike reaches it.

[evilone]

Weigh it the next time it's off, i'm curious. I hear the 99-01 clutch is lighter than the 94-98 clutch too, just a fyi. I'll weigh my 1995 and 2000 clutches soon to check the difference.

[Wheelman-111]

Greetings:

Good info rat thar. No matter to me; my clutch is the Polini Goody 2-Shoes Adjustable. Never weighed that, neither.

[maddog]

hey yum yum, just worked on this half honda/ jog engine and it blew my mind but i it to go 40 mph, now that guy from n.c. that claims he has final drive gears needs to tell the local boyz

[eliteguy50]

All the flywheel effect weight is to smooth out that 1 firing pulse per revolution. These thing vibrate bad enough with all that weight. Less will make the vibration worse. For racing, who cares about vibration, you don't ride that long, but for s street cruiser, vibration means tire out the rider sooner. Usually the butt first.

Don't forget about lower rpms without stalling.

[Wheelman-111]

Greetings:

Uhhh, ... Whut?

A post totally irrelevant to the topic, and just about incomprehensible in itself.

Only one explanation: the Dog is a Bot!