Modern Vespa

Does anybody know if the Malossi over drive kit is compatible with the performance cam and cylinder kit from them? I've got all 3 installed on my 2020 GTS 300 HPE and the revolution limiter still kicks in at 79 mph. Right after installing it 77 mph was the top speed (a loss of 2 mph) however I then put some 14g rollers in after reading a post about the correct weight rollers to use. This gained me 2 mph but now I am back to the original top speed. I calibrated the traction control system as well and it gained me absolutely nothing. I have a higher top speed with all original parts and the upgraded tone wheel (84 mph).

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I'm just curious, but do your top speed numbers take into account the almost ten percent 'optimistic' speedo error these things have?

Firstly, how is this different to this post of yours
MALOSSI OVER-DRIVE KIT 22/45

You say you're hitting a rev limit. Have you recorded the your rpm + speed while riding? If not, I strongly suggest you do.

Have you tried on the stand (with asr off of course).

Did you also install the forcemaster? That raises the rpm limit and speed limit. If you didn't then how did you compensate for the increased flow from that camshaft? I have, and it's faster than 79.

any chance of a detailed list of what you have installed?

BTW the overdrive kit will reduce acceleration (as indirectly replied in your previous post).

The difference is I am asking if the components are compatible. Before I asked if I needed to upgrade something.

When I say I am hitting a rev. limit I literally mean that the revolution limiter is engaging and decreasing the speed. It is my understanding that this occurs at a very specific rpm. And that this is a hard stop for the engine and that it cannot go above this. And any increase in top speed is the result of lowering the rpm of the engine. Or tricking the engine into believing it's at a lower RPM then what it actually is (for example changing the tone wheel). Hence the slower acceleration. I could check the rpm and speed while riding to see if the revolution limiter is working correctly.

As for the force master upgrade this would have been a much appreciated suggestion in my original post.

As for what I currently have installed it is the Malossi performance cylinder, the malossi performance camshaft, the malossi overdrive kit and the multivar variator kit. I also had the delta clutch but I reverted back to the stock to cut down on the variables.

As for the top speed I do take into account the erroneous readings the speedometer gives. The speedometer reads 84 mph but after checking it via radar detection and pacing another vehicle it appears to be 5 miles off at top speed

I assumed you had it when I read that post, only guessed you hadn't when reading this post.

when changing the cam in any vehicle it is generally considered appropriate to either remap the ecu or use some sort of secondary ecu such as the forcemaster. this is why malossi makes it. It's much more likely that you are hitting the speed limiter not the rev limiter. Yes there are two different limiters. It's easy to hit the speed limiter even on an unmodified gts300hpe. The forcemaster will solve this for you.


There is also the option of changing these limiters in the ecu. You'd need to use something such as ASW-Next* or Kess3* to read the ecu bin. can then easily modify it using TunerPro (free) with the XDFs that I make.

* some bike and car tuning shops have kess3 as it can be used with many vehicles depending on what licence the shop paided for. asw-next is less common as it's for scooters (asw = advanced scooter workshop)

That is very interesting. The service manual and the owners manual make no mention of a speed limiter. They only mention the revolution limiter in great detail and show the electrical diagram for it as well. How does this speed limiter work? Because you can change it by modifying the ECU it would have to have a digital component to it, but how does it know how fast you are going? Does it share the same sensor as the revolution limiter?

yes but it's well known that since the introduction of the hpe and miug4 that a speed limiter was added. the sensors are connected to the abs. the abs sends both the front+rear via the canbus to the ecu. the ecu then implements both asr and also the speed limiter (which reduces fuel).

the forcemaster increases the fueling across the whole range (by intercepting the wires to the injector). it's increase is greater than the amount that the ecu's speed limiter reduces it. so this means enough fuel to keep accelerating past the limiter.