Modern Vespa

This past weekend, I had my 6,000 mile service on my MP3 500. I had them put in a set of 21 gram Dr. Pulley sliders as part of the maintenance. After riding them for a few days and putting about 100 miles on them, I thought I'd share my impressions on them, since I hadn't seen them reviewed on here before now.

First off, let me give my reasons for choosing the weight I did. My primary goal was to maintain or drop the number of RPMs I'm spinning when doing highway cruising. I also wanted the improved lifespan of the sliders. I was also hoping to change the characteristics of the transmission when getting on or completely rolling off the throttle, though that was a tertiary goal. Since the stock rollers are (I believe) 21.9 grams, I chose the 21 gram sliders.

My riding style tends to be very conservative. I think I can count the number of times I've been at a wide open throttle on my MP3 on one hand, so I wasn't looking for drastic gains in acceleration. Most of my riding is highway, whether that's back roads or Interstate, so a lot of the time, I'm holding steady on the throttle at 45 MPH or above. In fact, when taking off from stop signs or lights, I usually only open the throttle to about where I'll have it for cruising, letting it gradually make its way up to my desired speed.

Now, the results:

If I hadn't known that they were putting in the sliders, I probably wouldn't be able to tell that they're in. Which is pretty much exactly what I wanted.

The transmission does seem to hook up a little bit sooner than it did before. Both the ramping up and the engine braking feel smoother than they did before, and I don't think I'm hearing as many clunking roller sounds from the transmission as I was before when getting off and on the gas. The engine breaking in particular seems to be more gradual than it was before. It used to be that if I let it engine break to idle, it would sputter between about 2500 RPMs and where it finally disengaged and dropped to idle around 2000 RPMs. In fact, it's choked out and died there many times in the past. (A problem that was at least partially fixed by removing the evap canister) Since putting in the sliders, I haven't heard it sputter at all when coasting to a stop, but I haven't always been paying very close attention to that, so I'll keep my ears open and see if that really is the case.

As for the engine revs, I'm very happy. I tried to watch on my way to the shop to see what I was spinning at given indicated speeds on the old stock rollers and worn belt (6500 miles). The numbers I've seen with the sliders have fluctuated a bit, but I'll give my best recollections of what I've seen.

Speed ----- Stock RPMs ----- 21g Dr Pulley RPMs

30 MPH ----- 3300 ----- 3400 to 3600
40 MPH ----- 3950 ----- 3900 to 4000
50 MPH ----- 4400? ---- 4300 to 4400
60 MPH ----- 4800 ----- 4700 to 4900
70 MPH ----- 5600 ----- 5400

I'm not exactly sure what my revs were stock at 50 MPH, but I think that was pretty close. And the 30 MPH might have been slightly downhill stock, so that might be a little skewed. Overall, though, it seems to be spinning a little faster at low speeds, about equal in the middle, and spinning slower now at Interstate speeds. I'm seeing similar trends above 70 MPH, but I don't have any hard data since I've only been up over 70 a little since the sliders were installed. The speed limit in Illinois is 65 and I really don't like to speed...

So, my overall impression is that the 21 gram Dr. Pulley sliding rollers allow the engine to spin at very similar revs as the stock ones at low to medium speeds with a marked improvement at high speeds. Due to the slider design, they also gave improvements in throttle response when rolling on and off the gas.

Mark

Interesting post, but with the same weight as original there will not be much improvement.

your measurement
30 MPH ----- 3300 ----- 3400 to 3600
40 MPH ----- 3950 ----- 3900 to 4000
50 MPH ----- 4400? ---- 4300 to 4400
60 MPH ----- 4800 ----- 4700 to 4900
70 MPH ----- 5600 ----- 5400

mine with standard rollers
converted to miles per hour
speed - 8 rollers - 6 rollers - 4 rollers
012 - 2100 rpm - not measured - 3000 rpm
025 - 3000 rpm - not measured - 4000 rpm
038 - 3700 rpm - 4000 rpm - 4500 rpm
050 - 4500 rpm - 4500 rpm - 5000 rpm
062 - 5200 rpm - 5200 rpm - 5500 rpm
075 - 6000 rpm - 6000 rpm - 6000 rpm
088 - 7000 rpm - 7000 rpm - 7000 rpm
100 - 8000 rpm - 8000 rpm - 8000 rpm

So if you want to see some actual improvement, remove 2 sliders and for a whoooooahhhhhh feeling remove 4

Yes, I saw your thread (and read your blog) after I posted this. I'm very intrigued by your results. Unfortunately for me, I don't have the tools to take apart my transmission As far as I know, I'm also not close to anyone that has the parts and skills to do it...

Mark

Thanks for the review, one more to our growing list of "mods".

Glad I can help. I hadn't seen it done, so I thought I'd be the guinea pig, and I'm pretty happy with the results

Mark

I'd like 19g. 16 g is easy to find, but lighter than I want.

Email Paul at Union Materials
paul@unionmaterial.com

I've written Paul three times over the past several days but only got a response to my initial inquiry about recommended weights--nothing yet about how to actually place an order for the sliders. Hopefully he's just busy and hasn't gotten out of the "direct-sales" biz, but if anyone gets a bite regarding how to place an order, please post the info here as I'm looking to buy a few sets as well for our 500s in the garage...

Thanks!

the size you need are 25x17 with the weight of 16, or 17 grams, these are what most folks like , The 15 grams are very smooth to me and I changed them to the 17 grams for more of a feeling . they work good with the Fuzzy washer 1mm. the washer is inaddition to the stock washer to give you a total of 3mm.

edit for got to add you will only need 1 set per scoot as they will last for at least 10,000 miles or more.

Sorry...I wasn't clear in my last posting--I have already settled on the weights I'm after thanks to all the great info on this forum (and I already have two Fuzzys on the way thanks to the re-issue); it's actually getting the sliders ordered that I'm having trouble with--no one has them in greater than 16gm weights that I can find, and I was actually looking for a 17, 18, and 19gm set to experiment between our two bikes over the next riding season.

I just PMed him as well. EBay only has 15g and 16g...

Yes, I can confirm that it's the right contact info for Paul. I had sent him a PM initially on here, then continued conversations with him through his e-mail. I got mine less than a month ago.

Also, don't forget that you can mix and match weights to create different apparent weights. So, for example, you could get a set of 19s and a set of 15s, alternating them to make it work like 17s... Or 21s and 17s to make 19s.

Add in Gran Canaria's roller removal, and you could probably get some wild results. And even more roller life for your money...

Good luck!

Mark

Oh, I forgot to add that I have another contact with Union Material, the person that actually fulfilled my order. I'd think it's probably better to contact Paul and order through him, but if you can't get ahold of him, let me know...

Thanks; I'm patient to a point, but I'd love to try some sliders while I still have some riding season left. I'll give a shout out if I don't hear back in the near future...

Anyone managed to get in touch? He replied to my PM saying 'use my email' so I did and got no reply...

Did you ever get a note back? It took an extra couple of days for me, but I finally got a note back from "Esther" saying that Paul had passed my note to her for the purposes of placing an order. I went ahead and bought a set of 18 and 19 gram weights (want to do some experimenting) for my wife's scoot and my own.

Cool, detailed info ... anything new/different or "updated" you may want to add now ??

Well, I've had a couple of variator failures since then, so I stopped using the Dr. Pulley sliders. I can't say for sure that they were the cause rather than it being just the normal wear on the parts, but I also would no longer recommend using them. If you want some rollers with different weights than stock, I believe there are some other companies that make them. I'm pretty sure the set I put in during my last rebuild were from Malosi, but I can't remember for sure and I just don't care enough to go look it up...

Mark

May I ask, how many miles on your ride ?

A little over 53,000.

I use a mix of stock Piaggio roller weights. 4 stock 25gram weights (black) in combination with 4 21gram weights (turquoise) in a staggered pattern (25-21-25-21 etc) for a overall combination of 23 gram.

Zero issues and no more dreaded bucking in the last 5 years.

Also, the Piaggio rollers show very little to no wear, in comparison to Malossi weights which seem to made from recycled chewing gum.

thats the thing, 50:50 25g/21,4g - works perfect ¨!

installed 19g sliders in my 500. wore through three rear tires in about 9000 miles. work better than rollers in my experience. rollers wear out too fast.