Modern Vespa

Has anyone ever fitted 19gr dr pulleys to an MP3 500? If so what are yr views....? Am after lower revs at cruising and better economy, I would also like to improve on the judder that I get on taking off at small throtle opening. thanks in advance for the feed back!

I have a set myself--but haven't installed them yet . From what I recall reading, 19g was considered fairly close to stock, enough so that the differences might actually be neglible on installation.

I bought a set of 19s and a set of 17s with the intention of trying a mix and match combination just to see if I noticed a difference at varying weights and configurations; but quite frankly, I haven't had enough time to actually break down the bike and install them at all. I'll be watching this thread for any other useful contributions as well...

the thing is that dr Pulley told me to use 18gr which are lighter and I want lower revs when i cruise....I dont use it alot in traffic conditions and wouldnt mind a slower acceleration but want
better MPG's

I had 17g's in mine --- way better acceleration at all speeds - adding in passing accelaration - but ate up my mpg - and reduced top-end by at least 5mph --

now on my new one - back to stock - less aggro riding - mpg is back and high end is reached with not much coaxing ---

so maybe 19g is the way to go

enough to keep the low end grumbles away but still keep more of the top end and the mpg

They are pretty much same as stock. I would go to 18 if you want a little better than stock or 17 if you want romp 'em stomp 'em.

so 17.5 are stock equivalent??

19s are stock equivalent. I went with 18s, I do have better acceleration, the grundle is gone and not much loss in top end speed. Cruise down the freeway at an indicated 74 MPH (about a real 67 MPH) at 6,000 RPM. Perfect.

Actually 21 grams is stock weight on a 500.
I do wish people would quit talking about losing top end. I have 17g weights in mine and got a ticket clocked at 85 on the straight and flat. Do y'all *really* feel a need to take a scooter with 12" front wheels up to 91mph or wherever the limiter kicks in? The acceleration improvement is much more valuable than the top end.

So the real question is what do you see as the affect on your mileage with 17g wieghts?

I'm happy with my 18 grams.

Much smoother takeoff and gas mileage/revs/top speed haven't changed noticeably at all.

yeah some need to drop the rpms by 1 or 200 so get the mpgs to increase .0066789 mpgs when averaged over a coast to coast hypermileage run versus having a better acceleration to get the hell out of the way of a cager whom is not paying attention talking on the cell or texting.

I'll sacrifice a mpg anyday of the week for better response. I'm not going to do the math but the pennies saved on a gallon of gas over a 1 year period is like what? $5 ?

I get 56-58 mpg after the ECU update. best ever. If I'm really flying low - like my trip across Texas a few weeks ago where I did mostly 80-85 it got as low as 52 mpg.

I have no idea how you get such great mileage. I've gotten the ECU update (unless the dealer lied to my face and took my money ) and I've never averaged higher that 52mpg.

Even when I keep my revs around 6k on highway with no WOT and conservative acceleration, I usually get around 49mpg.

I've cleaned out my airbox and everything else looks great. MPG is the same with stock and Dr Pulleys as well.

Just filled up yesterday. 134.5 miles and took 2.42 gallons to get to the top of the neck. I just calculated that to 55.58 mpg.

I'm jealous... I wonder what it is that makes such a difference in gas mileage. Are most people averaging what you are after the ECU update? If so, I can only assume that my dealer messed up or didn't bother doing the update.

It could depend on how many miles on the engine? My 400 didn't get up to mileage until after 10,000 miles. The advise to ride it like you stole really pays off from a n engine break-in perspective.

i get around 65 uk mpg, the bike is fully standard, rollers and all, and I dont drive that slow, on my way home there is a stretch of road where i touch an indicated 140km/h uphill on a daily basis .... will be getting the 18gr sliders --- thnx for the help !!

I found that my 500 gives me the best mpg at about 4-5k rpm, higher than that even cruising the mpg's go down, also get up to the 5k gradually not WOT then levelling off, I have 35k kms on it and i hav got used to the bikes ways by now

Ok, I agree with OAD. The whole "worry" and angst over fuel mileage is a pet peeve of mine, so I messed around a bit.

In advance, I'm sorry, I'm a recovering CPA and am mostly healed from that affliction, but not completely.

Assumptions:
Miles ridden - 20,000
Fuel cost - $4.00 per gallon

At 50 MPG, your total fuel cost is $1600, or $0.08 per mile
At 55 MPG, your total fuel cost is $1455, or $0.0727 per mile.

So, for every 20,000 miles ridden, your cost difference is $145. So, unless you are riding a bunch of miles, this just isn't a lot of money over what for most of us is a 2-3 year time frame.

Or, every 5 MPG saved (or lost), saves (or costs) you 3/4 of a PENNY per mile.

So worry and angst if you must, but I'll worry about other things. Make my MP3 peppy and fast from the start.

Rant over...

thank you for doing the math for us. gotta go spend some partial pennys soon.

It amuses me that in the US you scooter riders worry about mpg, whereas even here in the UK where the cost of fuel is about 2.5 times yours, it is still a tiny fraction of the ownership and riding costs (all other costs are pretty much the same), and no-one riding a scooter gives a shit.

Belts and tyres are the big ongoing costs for both sides of the Atlantic and just those two alone far outweigh fuel costs per mile if you get a dealer to do the work. Add on oil and brake pad changes, the odd bit of bodywork repair, and the fuel costs vanish into total insignificance.

We're just reminded of them because we fill up so regularly, and we tend to forget the pain of handing over the Visa or whatever at the dealer every so often...

Our fuel is still far cheaper than beer - yet we all quite happily buy *that* without too much quibble.

Sod mpg comparisons on Piaggio bikes. It's almost an irrelevance.

I've used 3 sets of sliders. I started with 21g for about 5k miles. I went to 18g for about 7k miles, then back to my 21g for another 6k miles. I just went to a new set of 19g sliders.

Now, it's been so long since I used stock rollers that I can't really remember how they felt. And it's been over a year for the 18g's, so I don't really remember them, either.

After almost 12,000 miles on the 21g, they still look practically new, so if you're worried about wear, don't be.

Comparing the 19g to the 21g, you need to spin the motor up faster to accelerate smoothly with the 19s. I'm noticing a lot more shuttering/vibrations at low speeds and low RPMs now than I did before.

Now, to be fair, between when I took my bike apart (to repaint it and do my service) and when I put it back together with the 19g sliders, I did ride my Ninja for a month and a half, so my memory may be a little faulty. And I haven't run a full tank since I put it back together, so I can't say if there's a MPG difference. But I think there's going to be a bigger difference due to riding style and speed than due to the difference in slider weight.

Mark

Its not necessarily about penny pinching. Low MPGs may indicate something wrong with the bike or that it isn't running efficiently which may cause more wear and tear. Though I wouldn't complain if the gas tank was bigger (hate having to fill up so often)

I enjoy having my bike run at peak efficiency because it makes me feel warm and fuzzy inside knowing that I did everything I could to make her happy

Could also be the Fuzzy Washer - it puts you on a better torque curve so perhaps when giving throttle less gas is needed. I also have an aftermarket muffler - maybe less backpressure... I dunno - it is what it is. I know the 16 gram weights ate my lunch on gas mileage.

This may not be the best place to discuss the physics of the Fuzzy Washer, but I've long wondered the same thing. It's spreading your variator plates apart further, right? That means that the belt will slide in closer to the center, and would be turning the rear wheel more per engine revolution due to a lower gear ratio, right?

Turns the rear wheel *less* per engine revolution, but yes, a lower gear.

OK, that's what's always confused me. Why is it turning the driven pulley less?

Turning the rear wheel LESS per engine revolution.

I agree.

Just parenthetically, however, I usually don't fill up with 2.5 gallons of beer.

Because the belt is lower into the driving pulley, and further out on the driven pulley, each turn of the driving pulley moves less belt, and so the driven pulley gets turned less.

Oh! I've been thinking of it backwards this whole time!

Thanks, Jim!