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Sports Exhaust Testing- 50cc and 70cc Sports Mopeds- PART TWO


This is PART TWO of a 2 part blog.
Click here to read PART ONE which this continues from!

...The Leo Vince ZX-R (basically identical to the ZX as shown in our article Leo Vince ZX vs ZX-R Moped Exhaust Shootout) and TT make basically identical power on a standard 50cc only the TT at slightly lower rpm. This means the ZX-R will potentially result in a very slightly higher top speed than the TT (perhaps 3% higher) but otherwise there really is no performance difference between them.

It is commonly rumoured that the Leo Vince ZX starts to come into its own compared to the TT when a 70cc sports kit is fitted, we will soon see!
As it stands there is nothing to choose between the ZX and TT on a 50cc standard cylinder kit. They both make good peak power at reasonably low rpms (this is why they are popular) but the power drops off quite quickly once the variator is changed all the way out meaning the ultimate top speed will not be the best. In fact the power on both pipes initially drops untidily to under 5hp at 9,500rpms... this would probably result in a 'wall' preventing any further increasing in top speed as in reality the speed at which the moped would be going at 9,500rpm would probably require more than 5hp to continue accelerating. Curiously the Giannelli pipe would probably therefore make the same top speed as the Leo Vince pipes as it virtually meets the Leo Vince pipes at this drop off point despite it showing a lower peak power.

If you look at the Yasuni Z the graph is essentially identical to the Leo Vince graphs but 'done properly'. The untidy drop-off of the Leo Vince pipes is gone, the power band is much wider yet whilst almost fully encompassing both Leo Vince graphs within its own graph.
This would mean the Yasuni Z would perform identically to the Leo Vince pipes except that it would also offer a significant increase in top speed over the Leo Vince pipes and be much more forgiving when being setup. It is rumoured that the price of the Yasuni Z performing so well on 50cc standard cylinder kits is that is does not perform so well if you later upgrade to a 70cc sports kit. We will investigate this in the next 2 graphs.

The Stage6 pipe does what it does best, it's an 'angry' pipe which likes to rev fairly high and make high peak power and top speed. The powerband is reasonably narrow which is why on bikes like Aerox which have standard variators which don't respond well to tuning it can be particularly beneficially to fit a decent aftermarket variator kit which can hold the revs constant far more accurately within a narrow range.
The Yasuni R is basically identical to the Stage6 Pro Rep pipe only with a wider powerband. The top of the Yasuni R graph is flattened off by approx 1/4hp compared to the Stage6 pipe but normally it matches the Stage6 pipe without this flattening. It may be something to do with the specific bike used, but in any case the Yasuni R pipe would have by far the highest top speed on the standard 50cc kit still making a useable 7hp at 11,000rpm. This could easily represent up to a 15% increase in top speed for the Yasuni R compared to the Leo Vince pipes. __________________________________________________________

Polini Sport 70cc Cylinder Kit

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70cc Polini Sport moped exhaust dyno graph

Malossi Sport 70cc Cylinder Kit

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70cc Malossi Sport scooter dyno graph

The Malossi and Polini Sports 70cc kits in the 2 graphs above are essentially very similar.
Generally the Polini kit slightly outperforms the Malossi kit although on the liquid cooled engines it is often the other way around.
The pattern is almost identical to when fitted to the 50cc kits. The Leo Vince TT is still essentially identical to the Leo Vince ZX-R meaning there is no real truth to the thinking of the TT being a 50cc pipe and the ZX a 70cc pipe. They both perform virtually identically on both 50cc and 70cc sport cylinder kits.
Interestingly the Giannelli 'Next' pipe has come into its own here and now has a virtually identical graph to the Leo Vince pipes. Unfortunately the Endy pipe has gone the other way making substantially less power than the other sports style pipes and even then the power it is making is at a far higher rpm than it should be considering the low hp.
At this point we even took out another Endy pipe and re-ran the testing to see if there was a problem with the specific pipe but the replacement pipe performed in an identical manner. With the Malossi kit fitted the Endy pipe is very significantly outperformed even by the standard look Tecnigas pipe which made significantly more power and at significantly lower revs. In fact the Endy pipe made 6.7hp at 9,600rpm... the Tecnigas 'Silent Pro' was able to make this at just 7,600rpm.
The Endy is generally thought of as similar to a Leo Vince TT, but our testing always suggests it is in fact nowhere near.

Again Stage6 Pro Rep and Yasuni R are the top performers with the Yasuni R offering the advantage of a significantly wider powerband (much more tolerant to a poorly setup transmission) and potentially slightly higher top speed over the cheaper Stage6 pipe.

In all the pipes are relative to each other in an identical manner to how they were on the 50cc cylinder meaning that what works well on a 50cc will generally work well on a sports 70cc kit.

It's worth noting that the Tecnigas 'Silent Pro' makes 7.5hp on the Malossi Sport Pro 70cc kit at 8,700rpm. This is substantially more than any of the sports pipes were able to make on the standard 50cc cylinder kit AND at significantly lower rpms. If you want a discreet but very substantial increase in power a sports cylinder kit + the standard look Tecnigas can significantly outperform a standard cylinder with a sports pipe fitted. It would also be quieter (almost standard) with low engine wear (virtually same revs as standard) and very discrete.


Stage6 Sport Pro MKII 70cc Cylinder Kit

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Stage6 Sport Pro MKII dyno graph

This is where you would expect things to start to get a little challenging for the sports pipes. The Stage6 Sport Pro MKII is at the top end of the sports cylinder class and can also be used as a mid-race kit when setup correctly as discussed in our article Stage6 Sport Pro MKII Cylinder Kits- a closer look.
This means that all the sports exhaust pipes should perform well but with the higher end of the sports pipes we should be able to start to see some of the potential of the kit coming through. As with the Motoforce mid-race 70cc kit in the next kit the full mid-race potential of the Stage6 kit would only be seen when paired with larger carb etc. and much more careful setting up but we should start to see some of it's potential regardless.

We can see that yet again the Leo Vince pipes are basically identical although now despite still having an identical peak power to the Leo Vince TT the ZX-R will perhaps have a slightly noticeably better top speed than the TT, not enough to warrant 'upgrading' from a TT to a ZX even at this level of 'high sports' tuning.

The previous high performers i.e. Stage6 and Yasuni R have now really started to come into their own and would completely destroy the other pipes for top speed. We can see the work from Stage6 Development here whereby the Stage6 pipe and Stage6 cylinder is specifically designed to match together and its performance is exceptional. Even the Yasuni R can't beat it on it's home ground in this circumstance.

The Yasuni Z which was performing very well on both the 50cc and 70cc sports cylinder kits is now starting to move slightly out of it's comfort zone. It still performs with the widest of all the powerbands and the top speed would still beat pipes like the Leo Vince but we are starting to loose peak power now against some of the other sports exhaust.
Gianelli is still proving a very capable budget pipe although the way that the power drops off very quickly now after it peaks suggests it will start to struggle badly if we fit it to anything any more highly tuned. To be fair though it's a budget pipe and you would want to invest in something more suited if you were tuning any higher than 'sports' level in any case.
Endy yet again makes even less peak power than the Tecnigas 'Silent Pro'.


Motoforce Mid-Race 70cc Cylinder Kit

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Motoforce mid-race 70cc dyno graph

This graph above is just to throw all the sports class exhausts out of their comfort zone by fitting them to a mid-race 70cc cylinder kit.
At the bottom end the Endy and Tecnigas exhausts are struggling and now make less power on the mid-race kit than they did on the lower tuned sports kit. To be fair not many people would really have expected a 'standard' style exhaust like the Tecnigas to run in any useable manner on a mid-race in any case.
The rest of the pipes do the best they can out of their class- the only pipes with decent potential left now are the Stage6 Sport Pro Rep and the Yasuni R. The Yasuni R manages to make a very decent and smooth wide powerband which is quite an achievement considering vitually everything else on the bike is completely standard. The Stage6 graph shows potential but it looks like it would need work e.g. bigger carb etc. before it was able to deliver a useable powerband.


Just for the sake of interest, included below are some graphs of how each pipe performs on different cylinder kits.

It's important to note that the Motoforce mid-race kit shows less power than the Stage6 Sports Pro MKII kit in most of the following graphs. The reason is of course the sports exhausts used are out of their comfort zone and not sufficiently highly tuned to match with the mid-race kit to see its full potential. The mid-race kit would also need substantial setting up e.g. larger carb etc. to see it starting to work properly.

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Giannelli exhausts dyno graphs

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Leo Vince ZX-R Piaggio Dyno Graph

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Tecnigas Piaggio Dyno Graph

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Yasuni-R Piaggio Dyno Graph


Leo Vince TT vs Leo Vince ZX-R

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Leo Vince TT moped dyno graph

This graph above is a comparison of the Leo Vince TT against Leo Vince ZX/ ZX-R exhaust to show that there really is no difference between the two exhausts regardless of whether fitted to a standard 50cc cylinder kit or a sports 70cc kit. The ZX-R will always rev very slightly higher resulting in possibly very slightly higher top speed, but the differences are marginal.
There is no basis to the widespread thinking that the TT is for '50cc cylinder kits' and the ZX/ ZX-R is for '70cc kits'.


Exhaust Pipe Quality

As mentioned before all of the exhausts in the testing are E-marked which guarantees they at least meet basic EU requirements of workmanship and quality.
Performance is obviously very important, but so is quality. So what actually makes a good quality exhaust? Let's take a closer look.

One of the easiest ways to get a quick feel for the quality of an exhaust is to take a look at the number of individual cone sections an exhaust is made up from and the quality of the welding. Both of these factors significantly increase the developmental and physical costs and expertise required in not only developing but manufacturing the exhaust.
As a general rule the more cones the exhaust has the more highly developed (tuned) it will be.
Welding quality is fairly easy to judge even for the inexperienced but Yasuni is probably the ultimate benchmark here. We recently met with a commercial exhaust manufacturer who boasted as part of their presentation that they considered their welding to be almost as good as Yasuni!
Take a look also at the size of the silencer. Budget exhausts will tend to use shorter silencers than premium exhausts.

Let's take a closer look for example at the Endy pipe below
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Endy Piaggio Exhaust Pipe

we can see that this budget exhaust has just 3 cones making up the main body section of the pipe.

Now compare this to one of higher performing pipes from our testing, say the Yasuni R...
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Piaggio Yasuni R Exhaust Pipe

Basically twice as many cones. This isn't on it's own conclusive proof of anything but generally speaking the more cones in an exhaust the less compromises have been made in developing the exhaust. An exhaust with just 3 cones in the main pipe section is almost certainly going to be a budget pipe but of course some budget pipes are better than others!

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Giannelli Next Exhaust Pipe- Piaggio

The Giannelli 'Next' pipe in the above picture seems to take the cost-saving a little further and the centre pipe section although formed by 3 section shapes looks as if it was simply pressed out of 1 piece with the seams where it was joined clearly visible and the stinger piper from the rear looking like it was simply pushed in and welded on afterwards.
We can forgive this though, the pipe is the cheapest here, it is strong and robust and performs well for it's price. It's clearly not a premium pipe like the Yasuni or Stage6 but it doesn't pretend to be.
Whilst we're looking at the Giannelli picture take a look at the flange (where it bolts to the cylinder) and the flange where the silencer bolts onto the rear of the pipe.
You can see that these flanges are often rigid on budget pipes. This is ok, but it results in very high exhaust rigidity which is not tolerant of any mis-fitting or excess vibration. Say for example as one example the exhaust is bolted rigidly at the front before the rear is bolted up entirely, the exhaust is then under considerable permanent stress after the rear of the exhaust is tightened and can be prone to snapping cracking or other breakages. This is the reason that budget exhausts are often bulked up with small support 'brackets' welded on to help reinforce the high stress points
If you look at for example the Stage6 pipe below you can see how they pre-empt these sorts of potential problems simply by superior design.

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Piaggio Stage6 Pro Rep Exhaust Pipe

You can see that in the picture above, similar to Yasuni they have use a stub/ slip-on fitment secured by a spring rather than a rigid fitment with the silencer being additionally sealed with a rubber joint covering the slip joint (Yasuni silencers even incorporate o-ring seals on all the joints). These slip joints ensure flex and movement and result in the pipes being virtually unbreakable even when severely abused.

Hopefully there is something here to help you make a more informed choice when choosing a sports pipe for your 50cc standard or 70cc sports cylinder kit!