Modern Vespa

Ive got mp3 500 what size weights do i need to improve perfmonance

Not completely sure about the new 500's but anywhere from 15 gram to 19 gram are popular weights for the 2008-2013 Fuoco/MP3 500's. It's always a trade off- lighter weights will allow for better acceleration off the line but your top speed will be lower and your engine will rev more when cruising at 80 MPH. Heavier weights will lower the RPM, making for slower takeoffs but lower RPM while cruising. 19 gram don't seem to do much different from the stock weights.

I plan to use 17 gram DR Pulleys with a "fuzzy washer" (an extra 1mm thick washer between the primary pulley plates) when I crack my variator open sometime later this year. This seems to be the sweet spot for most people, I've read here on the forum. Good acceleration with not too much RPM increase at speed.

Use the search feature for "DR Pulley" and "Fuzzy washer" for much more information. Don't forget to replace the "horseshoes" too.

Once the variator is all the way closed it doesn't matter how heavy the weights are. So as long as the weights are enough to close the variator at ~6000 RPM neither RPM at highway cruising nor top speed is effected. This is assuming the same basic dimensions of the rollers/sliders.

Try using Search, this topic has been discussed so many times.
There is a difference if you have ABS, or No ABS from what I understand.

Keith,
Marietta, GA

@Madison Sully-

Good Point! The Fuzzy Washer is the thing that changes the geometry, which changes the RPM's over the whole range. Although the DR Pulleys are supposed to change the total variation of ratio (higher highs and lower lows) compared to round weights, according to their website animation.

Where do you get fuzzy washer from ?

I have some somewhere. I will look tonight. I think I have varying thickness ones also but I think the 1mm is the optimum.

OP's answer seems to be 19g. Depends somewhat on what exactly the OP wants
Dr. Pulley sliders: what weight? (2016 MP3 500 Sport ABS Dr. Pulley sliders: what weight? (2016 MP3 500 Sport ABS)
Aprilia I believe uses the same engine and there is a separate Aprilia forum. This is correct. Within sensible limits the amount of weight does not effect top speed. What the weights do is to keep the engine at its optimum RPM range for acceleration and passing. What RPM you want depends on what weights you use. Fuzzy washer keeps the pulley halves further apart at idle which effectively lowers the "first" gear for take off. 500cc shouldn't have a problem pulling away. But MP3 is a bit heavier than a single front wheel scooter.

The principle effect of the Dr. Pulleys is exactly as others have said namely higher rpm during the acceleration phase due to lighter weight. The other benefit is that, because these weights are not designed to rotate and are made of tougher material, most people have found they have a longer service life than the cylindrical weights which often develop flats. If the chosen weight is too close to the originals the performance improvement will be nullified because the effective diameter of the Dr Ps is greater than the cylindrical originals. Hence the recommendation to go about 2gm lighter.

The effect of the wedge geometry tends to vary from model to model because it relies on how much design tolerances allow the variator pulley halves to close up further than the original roller diameter provides. On the Mp3 400 the wedge shape causes an overdrive effect which lowers rpm once the DPs have been thrown out to maximum radius. This reduces the tendency to hit the rev limiter at top speed and in favourable ( i.e. downhill or with a tail wind ) conditions allows a higher top speed. I can't comment on whether this applies to the bigger engine.

Similar comments apply to the fuzzy washer mod. The exact results will vary from model to model because the travel of the sliding pulley half will be changed to an extent depending on the 'spare' movement available in the original geometry. I would advise a cautious approach to this with a strip down for examination after just a few miles to make sure the belt is not suffering excess wear through running too low in the pulley.

I went with 21g sliders on my 2016 ABS and I'm pretty happy with them. I was concerned about them being too light but in the small amount of riding I've done since I installed them I don't see any problems at all. I wouldn't be afraid to try 20g or 19g now. The stock rollers are around 25 or 26g.

Fit a fuzzy washer, malossi hit clutch, 16g dr pulley weights and hi flow air filter.

This will happen with correct size lighter weights regardless of manufacturer or shape. This is where most of the Dr Pulley improvement comes from so it is a bit smoke and mirrors. Stock weights are not designed to rotate, under any load they cannot. They might rattle around at idle if worn. If they develop flat spots they are not rotating. Dr. Pulleys shape means they are smaller than stock weights at idle so allow the pulley halves to separate more IF the stock weights do not allow that already and their shape means at high RPM they can push the pulley halves further together than stock weights if the variator design allows for that.
Nett result : a slightly wider spread of ratios than stock weights. If the variator design allows that.

For this MP3 500 thread I believe more than a 2g difference is required even more than the 10-15% that is recommended.
Lighter weights will made the traction control work overtime if the MP3 in question has that.

I haven't noticed any difference at all. In another thread I was bitching about how I think the traction control kicks in too easily, if these had made it any worse I'd have yanked them out in a heartbeat.

Brent it was in your thread that I suggested this so glad it is not happening.

I found my traction control would light with one rider very easily over anything apart from smooth surfaces, especially when turning. In dry conditions I tend to turn it off now.