New exhaust (Leovince GP evo 3) does not give power output

[mellemeistel]

Hello everyone!

I am working on making a CPI GTR 70cc. It is after a lot of work making everything fitting nicely, almost coming to an end. My setup right now:
-Polini Sport 70cc, slightly ported
-19mm dellorto phvb carb
-Malossi multivar
-Polini 3g
-Jasil racing CPI crank
-artek air filter
-Leovince gp evo 3 exhaust

Im having issues with this leovince. When delivered (ordered from maxiscoot), there was no restriction in the manifold header, but i have no power and the engine is running badly and sounds restricted (yes, everything is for the rest adjusted as good as possible, no stuttering nor signs of a bad carb adjustment). With no load it wants to go to 12k with ease, when driving it goes not past 7k and driving 45km/hour tops. However, it is running pretty okay with the original exhaust where it surpasses 11k+ rpm when driving, with 80+km/hour tops. I Dubbelchecked to see if there is a restrictor in the manifold by opening it up, because the customer service of maxiscoot said there was one in there, but with nothing to be found after opening and losing my guarantee at that point   
Really strange, i could not find anything like a restriction and im having still no power gain while, like i said, the original exhaust gives so much power. Tested the original exhaust without a bracket mounted tho. Now the original exhaust just does not fit anymore at the bracket points because there is now a minarelli horizontal cylinder on there where the exhaust port is a bit different than the original CPI cylinder and exhaust port. Otherwise i could still use the original exhaust with my serup to just drive a bit faster.
I bought this GP evo 3 because i wanted something with not rustable steel and stealthy looks, like the original exhaust, but something with more power than the original exhaust. Now, with my actual setup, it drives 45km/h while it drove with the 50cc, and completely original setup, 65.
Something in that exhaust is restrictive- nor the whole design of it, but i dont know how i have to go further, i am in a bit of a dead end now.
So, i am asking you guys who know something this exhaust: Is there some restriction in the leovince GP evo 3, leovince exhausts in general what i am completely forgetting besides the restriction in the manifold(what i did not find), or did i mismatch this exhaust completely with my setup? I really thought some people with about the same setups did use this exhaust as well.
I really hope you all can help me out!
Yours sincerely,
Melle

[mellemeistel]

Nobody?

[oldgeek]

Oct 29, 2024 9:09:25 GMT -5 mellemeistel said:

Nobody?

The one I had years ago for the horizontal Minarelli was a big disappointment, almost like a stock pipe. I sold mine and moved on. I wished it worked as good as it looks.

[aeroxbud]

Yeah Brent had one too, but was disappointed with it.
Have a read through this www.pedparts.co.uk/blog/leo-vince-gp-exhaust-review-any-good

[mellemeistel]

Thanks voor the reply!
That is sad for me to hear☹️
I liked it because it was stainless steel. Do you guys have any recommendations for me, like an good low-mid rpm exhaust for a setup like this, and the best would be with some good rust resistance?

[aeroxbud]

I have tried most of the street pipes now on my aerox. The Yasuni eco had really good low end power. But ran out of steam higher up.
The Tecnigas Silent-Pro is a good all round pipe. But for me fitment was a right pain, as the mounts didn't line up.
The stage 6 street is the best performance. It actually has a higher rpm hit unlike the others. It came rusting already! 😬
You just have to use a high heat exhaust paint. Then every year clean and repaint them. It doesn't stop the corrosion. But it makes them last longer.