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Roller weight comparison on C650 Sport (24-22-20gr) using Obd data and Pbox

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Putnam

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Hi all,

Since I got my 2016 C650 Sport, I’ve been trying to get the maximum performance out of it. I got it recently, and it already had a Malossi variator and an Akrapovič muffler installed.

The first step was to install Arrow headers, and later on, I started experimenting with different roller weights (as shown in the title).

Throughout this process, the scooter’s acceleration was tested using a Racelogic PerformanceBox. OBD logs were also recorded using the Car Scanner app. Unfortunately, I didn’t have this app when I tested the 24 g rollers.

The road was always the same, but the air temperature was not.

I will compare the 100–150 km/h times, but through the PerformanceBox software, I also have access to all the intermediate timeslips, such as 56–142 km/h.

The tests with the 24 g rollers took place in mid-April, when the air temperature was around 15°C.

The tests with the 22 g rollers took place in both July and August, when the air temperatures were 27°C and 22°C, respectively.

The tests with the 20 g rollers took place in late August, when the air temperature was 32°C.


24 g

100–150 km/h = 7.40 sec (15°C)

RPM = 6600–6800 (estimated)

22 g

100–150 km/h = 7.36 sec (27°C)

100–150 km/h = 7.25 sec (22°C)

RPM = 6950–7150 (OBD)

20 g

100–150 km/h = 7.26 sec (32°C)

RPM = 7160–7486 (OBD)


The only way to eliminate the “air temperature” factor is to test the 20 g rollers again at a cooler temperature.

I was hoping to get a lower 100–150 km/h time, but I didn’t.

The scooter is supposed to produce its maximum horsepower between 7300 and 7700 RPM, without losing much power even at the 8500 RPM limiter. There are plenty of dyno charts supporting this.
 
Last edited:
Thanks for posting. Very interesting! In my case I use my 2016 C650 Sport mostly for shopping and local trips, often with a pillion, so I want the "slowest" acceleration LOL, I guess I will use 24g. Can you tell me what tool you are using to hold the variator? And where you buy your rollers? My 12,000 mile service is due. Thank You.
 
24 gr rollers is the best overall setup.

I have a custom made locking tool for the variator, which I also use for other scooters. I also use and impact wrench, where I first measure the axle distance to the ramp plate with a vernier caliper, mark it, and it seems to work also fine (I have verified with a torque wrench that this method also works).

But I am about to buy the Easyboost tool, since I plan to service the driven pulley.

The rollers were bought from a local market in Greece, but it is very easy to find, try the official malossi store.
 
OK, good. Since my belt is 10 years old I will replace it. I saw the Easyboost YT video and saw that their tool set can do more than just the belt job. It may be my only option.
The rollers are another component that splits home mechanics between those who see a need to replace them and those who don't. I suppose I will change them for the same reason, not so much wear as they are a plastic material and they are old now...
 
I looked at Dr Pulley Rollers for the C650 Sport. They range from 22g to 45g! I guess Malossi offers a lighter roller and different weights, Dr Pulley does not make 24g. I will look for the Malossi store next.
 
24 gr are round ones for the Malossi variator which my scooter has.
If you have the stock variator, try dr pulley sliders, anywhere between 43 gr (which I wouldn’t) to 28 gr (there are plenty of owners who tried and were very satisfied).

For your use, I would try 38 or 36 gr
 
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