Has anybody fitted a c20 Yasuni exhaust to their S9?

[tablist180]

I really would like one but It's a steep price if I can't make it fit.

[Areomyst]

What cylinder do you intend to use?  Often times if you use a high end exhaust like that on a standard sport cylinder (pretty much that's all that's out for the Super 9) then you will actually loose performance instead of gain it, because the pipe and cylinder aren't working together well.

My exhaust is made by 190mech in South Carolina.  I would have to double check with him, but I believe it's a C21 style exhaust, with his own twists of course.  My Super 9 though, is far from stock.

Moped Hospital used to cut the header pipes off of old exhausts and weld on Yasuni exhausts back when they were racing.  The Tenigas NONE is a good exhaust as well, but I don't remember what RPM range it's happy in, and they don't make that for a Kymco - you'll have to modify it.

What are your goals with this scooter?  If it's a regular daily driver I don't personally feel like you can beat the Leo Vince pipes.  Sure, they're lower revving but they're perfectly suited for a reliable street machine with mild tuning.

~Josh

[tablist180]

I agree, the ZX has been good for the last 6 years on the S9.

I will be taring it down this fall and rebuilding it with the hopes of running 11k-12k rpms, mild race set-up.

New crank and bearings, taller final gear set, and I was really hoping on a manufactured "mild-race" cylinder but it looks like they are hard to come by for the S9 AC.

We just had a rally here in Denver and I was introduced to a local Yasuni rep that told me all I needed to do was clock the flange, much like you stated.

So, I really am stumped on how to get a cylinder that will run high enough rpms to support a mild-race setup, unless I have a cylinder ported by someone.

I have moved from the city to the burbs so this scooter is for rallies and Wednesday night rides.

So really it just needs to be ridiculous.

What would you do to get a mild-race or race cylinder on a S9 AC?

Maybe a machine shop could work something out but I need to know more about a possible fit before I try to go that route.

Thank for the reply.

[Areomyst]

There are a couple of options, but really no "easy" ones.

I use an Airsal cylinder that's ported a bit on the edge of reliability, but it's only for the 1/8 mile so...

You could fit a longer conrod to your crank, and use a Minarelli cylinder, then the Yasuni would bolt up, but you'll have to use a high-end cylinder to get the most beneifit.

If I had more time I'd post more, but it's super busy in here.

~Josh

[tablist180]

You are very busy and I appreciate your insight.

I think it will be interesting to see where this build takes me.

I'll be tearing it down this fall.

Thank you for your input on the matter.

In the long run, I want 10-11k rpms and a pipe to run in the powerband at that rpm.
The Yasuni may be a pipe dream.