Modern Vespa

I recently got my 2010 Piaggio Mp3 400 back from the 10.000 km service.
After reading the overwhelmingly positive feedback here regarding the Dr Pulley variator weight upgrade, I decided to replace the OEM rollers for the 17 grams.

I am however less than impressed. Before, I comfortably cruised around 100 kph @ 5400 RPM. Now with 17 g:s, the same speed gives me close to 7000 RPM. Quite a turn for the worse, I think (although, maybe not totally unexpected). The low end shuddering, choppiness and noise improved and the engine feels a bit more responsive overall, but I am also afraid that I am putting it under to much pressure with this "upgrade". It feels and sounds like it is straining more.

I also fear, from reading other posts here, that my mechanic might have put the weights in wrong somehow, even though I gave him pictured instructions and he said he had done this before. My mechanic also claimed that the Dr Pulley variator sliding pieces (ordered together with the weights) did not fit and he had to use stock sliding pieces. The mechanic, by the way, did not inspire too much confidence overall, but didn´t strike me as grossly incompetent either.

My questions are:

1. Could the fact my mechanic did not get the sliding pieces to fit be indicative of incorrectly installed weights? I have read on this forum that the sliding pieces are not as trustworthy as the weights, although I find it a bit weird they didn´t fit.

2. Is 100 kph @ 7000 RPM really normal for correctly installed 17 g:s? What RPM:s are normal, and how much worse is this for the engine, wear wise? Thinking about changing to 18 grams actually, to keep the smoother takeoff but reduce engine wear - but if nobody else is getting these high numbers on 17 grams, I want to check if they are installed properly first.


Any feedback appreciated!

the sliding pieces sometimes need a little massaging to slide easily on the back plate. they sometimes have a mold line on them.
and I find them a lot better for wear than the stock ones, can get 3-4 times the amount of use as compared to stock.
the 17 gr weights are a bit much for 400's. should have gone with the 15's. the 500 owners are using the 17's for the most part.

I question the mechanic if he installed the dr pulley sliders correctly.

Something's not right here. Those weights are on the heavy side for a 400 and should give lower rpm not higher. I used Dr Pulleys of between 14 and 15 gm which do give 7000 rpm under maximum acceleration. It is also possible that the variator has been incorrectly assembled and is not closing up as it should.

Agreed. I have had 16 gram Dr Pulley sliders on my 400 for years (over 20 thousand miles) and never had such high rpms. The 17s should be about the same as stock rollers. 15s give better low-end acceleration, but cut the top speed somewhat (so I've heard).

Thank you for the swift replies, which basically confirms my suspicions.

But arrrgh! I should never have let that hack near my bike! You wouldn´t believe how difficult it is to find a decent MP3 mechanic in Sweden (or maybe you would). I also noticed that after him changing my break pads, the breaks are even worse than they were before, and it now also pulls to the left while breaking indicating a malfunctioning front right brake. So "grossly incompetent" maybe was accurate after all in my mechanic´s case.

Sorry for ranting. Anyway, I now have to correct this, and I am seriously considering opening the variator myself to have a look. I think I am handy enough to pull it off, with the right tools. From what I read on this forum, it´s not that big off a feat, right? It looks feasible on youtube at least .

And lastly: I now have to step off the accelerator a bit with the bike until I have this sorted out, keeping it around 70-80 kph @ 5000 RPM - do you think this is sufficient not to harm the engine too much? Or would you simply park it (I am depending on it for my daily commute so if I can use it still, I will).

Thank you again for sharing your invaluable experience.

You were saying that 16g is ideal now your saying 15g?

As far as I've read 18.6g is stock on the 400 (21g I think on the 500) and so DR Pulley (per their website) says to go with a 10-15% reduction in OEM weight.

Per Dr Pulley that is 16.74g
17g is approx 9% reduction & 16g is approx 14%.

All I know is that my 400 has run beautifully with the 16 gram sliders for over 20,000 miles. Good low end, good top end on the freeway, and excellent mid-range acceleration.

I am running 17gr weights and fuzzy washer one mine with no issues. I do get some slight chatter if the clutch is cold, HIT, but I am very impressed with the mid range improvement after adding the fuzzy washer mod. 20km/h to 100km/h is impressive. After 100, it feels normal like it was without the fuzzy washer mod. If I sell next year, then I won't bother with 16gr weight,s but we shall see.

you can check a thread from me about 1 yr back where I had them in backwards. it has pictures of correct position incase you are still unsure.

thread title "80kmh @ 9000 rpm after fuzzy washer and dr sliders"

Did you loose any top end with those 16 or find you are traveling at say 75mph and find the engine revs even higher?

I understand that lighter helps with take-off (rpms can build faster on the motor) but still wonder how lighter affects top end spend and rpm?

I just found out my mp3 only has 2.5K on new rollers and belt from the PO so I have some time till I buy.

The clever thing about Dr Pulley is that the reduced weight gives an increase in RPM during acceleration but the shape gives reduced rpm once the weights have neared the outer limit. People who want higher rpm at top speed tend to also fit the "fuzzy washer" which prevents the pulley halves closing fully but if you want lower rpm for more relaxed cruising Dr. Pulleys are good.

Thanks for explaining it that way. I understood the Fuzzy washer gave higher rpms from the start but did not realize the increase in rpm stayed that way thru the whole rev range.

So does the Fuzzy negate the lowered rpms at high speed caused by using the DR Pulleys? Sounds like they cancel each other out.
I've never used a machine that spun this high anyway when going 75mph.

So does the Fuzzy with the DR Pulley allow for higher top speeds vrs what sounds like lower rpms at high speeds using only DR Pulley's?

I haven't tried the fuzzy washer so I can't tell you about the combination. My experience of Dr Pulleys is that the engine is less likely to hit the rev limiter and downhill top speed is higher but uphill or into a headwind may be a little lower. The fuzzy washer seems to be preferred by those who want a more responsive engine at high speed but this may be at the expense of fuel consumption.[/quote]

I don't want decreased fuel consumption for sure.
Some of my western loops require 150+ miles between gas stations.

so is 17 or 16s you have in there?

" Thu Jun 30, 2011 12:19 pm flag quote
I had Drew at Sherman Oaks Vespa put a set of sliders on my MP3 400 at the last servicing. There is simply nothing bad to say about them. I went with 17 gram sliders, the medium of the suggested weights (18 gram would be like stock, 16 gram would rev higher but might limit the top end). The acceleration is better and smoother - that early lag when taking off is just about eliminated. The clutch says engaged longer as I slow to a stop giving more engine braking. They cost less than stock rollers and last longer.

What's not to like?
Michael

Please don't try to corrige me. I'm incorrigible."

Damn.

Amazing how malleable memory is.

In the future everything we say or do will be recorded and saved.

The Fuzzy Washer affects the lower rpms only. Once the variator has open it just spins itself silly on the drive shaft.

No worries man.

So are you then truely using 17g on your 400?...and are happy with the performance? Are you a commuter or ride for fun?

Have you done a rpm/speed chart by chance?
I'm curious how those cruising rpms compare to 18g?

Still looking for a 16g chart too so we have a full range for those of us who like empirical testing.

So I see we have 400 riders who are on 16, 17 & 18g sliders and those are working for them vrs what the "group" thinks is best.

If we were discussing gearbox motorcycles each of us would have different sprocket needs and thus gear ratios that worked best for us, so why should this be any different on these machines?
I know my wide open western riding needs will be VERY different than someone commuting in city traffic everyday.

18g (+/- 200 rpm on a 400)
Dr. Pulley success! 100 KPH = 5200 RPM, 18gm, MP3 400....
60 kph = 4200 RPM
70 kph. = 4500 RPM
80 kph = 4800 RPM
100 kph = 5200 RPM
110 kph = 5500 RPM
120 kph = 5800 RPM

> So I see we have 400 riders who are on 16, 17 & 18g sliders and those
> are working for them vrs what the "group" thinks is best.

And some of us are running 15g sliders, very happily!

Yes, it seems that I have 17 gram sliders.

I glanced at the tachometer on the freeway yesterday. Between 100 kph (approx. 60 mph) and 120 kph (approx 72 mph) it read between 5000 and 6000 rpm.

I mostly commute. Mixed surface street and freeway, 19 miles each way.

So to wrap this thread up on my part: the mechanic did confirm he put the weights in wrong. With the 17 grams correctly installed, I get around 5200 RPM @ 100 kph, just as I wanted. The low-end grumble is gone and the bike is slighty more responsive. I may be imagining things, but I do think the engine rattles just a bit more with the new weights, but that may be unrelated.

All is well that ends well! Now I have a front brake bleeding problem instead, but that´s for another thread...

Thanks. I'm going with 17s after all (not 16s) as I want high cruising speeds and smooth take offs. I'd say those you love 16s & 15s might be city commuter folk who need fast take off speed above all...that's not me (thank god I hate cities!) as i'm out west and ride big open western roads with fast sweepers and twisty roads.

This also jives exactly what DR pulley says that a recommended 10% reduction in size will result in better take off and similar top end, but keeping it stock will be similar performance but smoother.
Stock is 17.6 (400cc) and thus 17g is a 3% reduction and thus slightly better performance.

Dr Pulley does not have any issue with going with stock #s but I'm sure most go lighter as the scooter culture seems to be start with too small of a motor and try and make it slightly faster by spending alot of $.

I like this discussion went along the lines of figuring out what's works best for the indiv. vrs an umbrella statement this what you should use period!