Modern Vespa

Yep, it's the Noob again, back with a few more questions before I pull the trigger. I've be searching this for a while now and thinking of going with the 17g or 19g for my MP3 500 with Fuzzy Washer installed.

I know its based on driving styles, so let me give you my circumstances to assist with any suggestions. I live in a rural country area, but like spending time in the city with friends & family. The 17g sounds like fun driving around the city, but I would also like to feel like I'm not stressing the RPM's while driving 70-90mph back home on the long hwy stretch.

1. I would prefer to stay within 6k-7.5k RPMs while driving on the hwy, is this too much to ask for with the 17g Dr. Pulley's?

2. Is there much difference between the 17g and 19g in regards to loss of top end speed and/or MPG?

3. Does question 1 and 2 make it seem like I need to go with the 21g Dr. Pulley's LOL?

Also, I have heard different people saying I need (25 x 17) and some say (21 x 17) Dr. Pulley's for the MP3 500 , can some one clarify the size for the MP3 500?

Thanks

Just checked the invoice from the last time I ordered sliders (a set of 19s). They are 25x17 for the 400/500. For a 250, you'd need 21x17.

Mark

I believe you lose top speed and MPG with the fuzzy washer. The Dr. Pulleys give you smoother take off and lighter wts. allow faster acceleration. If you use that faster acceleration, that would lower your gas milage. So, you don't have to take advantage of the faster acceleration, but it's sorta fun.

After a little more research and weighing the pros/cons of fun vs MPG, my mind is made up. I'm going with the 25x17 17g's.
Thanks again

If you're going to be doing your own transmission service, why not order both? Then you can use one for a while and see if you like it before trying the other to see if you like them better.

Another idea: you could mix and match sliders from multiple sets. So, you could order a set of 17 and a set of 21. If you alternate them (17 - 21 - 17 - 21 - 17 - 21 - 17 - 21), you'll end up with an average of 19. The key is to make sure the sliders across from each other match in weight.

Just a little food for thought.

then if your going to do that just order a set of 19's. I only suggest doing this for 1/2 weights for extreme fine tuning. Like if you want 16.5 average.

The life span of the sliders and having a spare set around is minimal as they last 20,000+ miles

good call.

I made a mistake on the sizing on the other thread . You have the correct number 25 x 17 at 17 grams. Don't forget to add the 4 back plate horseshoes. when ordering from buggyparts it should be in one of the drop down choices. if not just call them they are good folks

OAD, thanks for everything man, I ordered the 17g's last night with the 4 horseshoes so they should be on the way... Now I'm spending countless hours trying to research how to do this labor myself on replacing the flat tire and operating on the tranny lol....
In life you have 2 types of people, you crafty veterans who can do everything themselves; then you have people like me, who just buy stuff because it looks cool at the time then have headaches trying to fix it! lol

Do you know of any links or youtube videos that explain the whole process of taking of the exhaust to get to the tire "for dummies". I know it seems like a quick fix to you, but to me its like heart surgery

In that case, yes, I agree just buying the 19s would be better than mix and match. But I was trying to explain the concept...

You're stressing too much. The Fuoco (500) shop manual is on line here and shows what you need to do. Honestlyput the bike on teh center stand, loosen the bolt on the clamp that holds the muffler onto the pipe, above that there's a flange on the muffler that bolts into the top of the swing arm- it's a big ass torx screw. Then there's the clamp around the middle of the muffler that holds it to the swing arm on the bottom. I think there's two more bolts at the front of the swing arm that need to come out - it really is obvious.
To get the rear tire off then you then have to remove the axle nut in the middle of the wheel in the swing arm, remove the bottom bolt and clamp from the right shock. Rotate the right shock out of the way and pull the swing arm off and then pull the wheel out.

Perhaps I am wrong, but I thought that the idea of mixing weights was that, at lower revs the lighter ones would take effect quicker and then when revs increased the heavier ones would come into play giving a good cross of acceleration versus top speed..................

If you're ordering some parts and tools for your scoot, you might order a muffler gasket in case you need to replace it after removing the muffler to change the rear tire. They're crumbly. Don't rock the muffler up and down when taking it off and you should be OK, but having a spare gasket is nice, just in case.

'Fraid not.

When weights are mixed, it's still the heavier ones that do the bulk of the work all through the rev range, the lighter ones are just 'there for the ride' in the main.

You have to go to ridiculously light weights all round for the top speed to be affected - and it's usually because the rev limiter is reached before the normal top speed is attained.

I don't totally agree with Jim about the contribution of mixed slider weights. Each one must be accelerated towards the centre so each contributes part of the reaction force which is pushing the pulley halves together. As we all know
force = mass X acceleration and
centripetal acceleration = radius X (speed of rotation) squared
so the force from each roller is proportional to its mass and therefore if you have mixed weights the total force averages out accordingly.

Regarding top speed I believe ( but can't prove) that the shape of the sliders actually drives the variator halves a little closer together than the standard rollers and this is why they give a sort of overdrive effect at top speed (at least on the 400 engines which I have experience of).

Proponents of the fuzzy washer achieve higher rpm once the sliders are thrown to maximum diameter because the fuzzy washer limits the maximum effective diameter of the front pulley which gives more responsiveness at top speed but more frequent running into the rev limiter.

Therefore with a bit of luck the correct sliders can give better acceleration and also lower rpm at top speed. Under favourable conditions the absolute top speed can be higher but conversely up hill or against a headwind it may be slower.

The exact effect of the sliders is very dependent on variator geometry so may not be the same for all models.

Regards Roadster

Thanks BubbaJon for this detailed tutorial, I will definitely keep it at hand while attempting this daunting task. I know I'm probably making too much of it, but I'm a first timer. I almost had an anxiety attack trying to install my Givi top case w/ brake lights and I still managed to blow a fuse doing that . So since all of my parts are being shipped and wont be here until next week, I'm going to take my sweet time doing this. LOL

About how long can one expect to use a set of these sliders? I just realized I have been using the same set for 4 years now.

Speaking from the 2016 MP3/500 Sport perspective.
I think Stock is just fine...
The Bike is very fast, and I would hate to get less then the 53MPG I am getting now in ECO Mode.

Oh... Someone Please come out with a replacement Gas Tank that's a little bigger!

Keith

I second that (the bigger tank).