High performance replacement exhaust

[triride]

Hi,


Sorry if this topic has been covered before.
I have now got through two chinese motor stock 66cc exhausts and am now thinking that I would like to replace my third with an updated high performance version
Has anyone got any suggestions on any exhausts that will give me a "bit" better performance?

Many thanks, Pete.

 

[GoreWound]

there are lots of expansion chamber exhausts available for these motors, but basically any exhaust that is more free-flowing than the original one will help.
that said it's gonna get loud!

 

[YesImLDS]

The best universal pipe is the SBP expansion chamber can basically be made to fit any bike. Now the most performance kind of pipe is a real expansion chamber pipe off a small dirt bike or other 2-stroke, but will have to be made to fit. I have a fatty pipe or a home made version of the "arrow snake pipe"

 

[triride]

Thanks for the info guys!

Just something I observed when my last exhaust failed (end cap fell off) I noticed a sudden increase in noise which is enevatable and a lot better power on low speed accelaration and pulling power up hills, that is why I want to replicate that power with a high performance exhaust

Thanks, Pete.

 

[GoreWound]

restricting your exhaust will (to a point) give you more low end power at the cost of some of your high end power.
a tuned pipe (expansion chamber) is meant to allow a backpressure wave in the exhaust to get you the best of both worlds.

in general though if you want your exhaust quieter you have to restrict is somehow, and by extension the more free flowing your exhaust is the louder your engine will be.

also when it comes to an expansion chamber exhaust there are a lot more variables than "is the pipe banana shaped?" the shape of the pipe is obviously a huge factor in it's ability to generate the correct backpressure wave, but other things like how long the header pipe is can effect that as well. having any length of pipe more or less after the 'banana' than the manufacturer intended can also effect the flow dynamics of the exhaust. not to mention if there is a muffler in there, or any bends in the pipe not imagined by the manufacturer of the pipe.

basically what I am saying is you probably have some reading to do.
in my opinion you should start with some copper pipe and solder if you are in the experimental stage (keeps your costs down while you get an idea of what you want from your pipe)

good luck, and have fun!

 

[triride]

Thanks again for advise!
I have commited to buying an "expansion chamber exhaust" (SBP - ES02) from Sick Bike Parts.com
Postage cost more than exhaust! No suppliers of aftermarket performance kit here in the U.K.
Will let you know how I get on with it, once fitted and tested

Cheers, Pete.

 

[KCvale]

You don't need to restrict exhaust to quite it down.
All you need to do is dampen the sound wave.

This was my personal ride a few years back and it has a SBP expansion chamber on it.

The silver silencer on the end is just a mesh tube the size of the output a 1.5" of open space which is surrounded with fiberglass.

I left the silver cover off, then just had the muffler shop around the corner bend me piece of 3" exhaust pipe header to cover the first silencer, and then weld a Glass Pack car exhaust on the end.

It lowered both the pitch and volume of the exhaust.
It didn't make it sound like a Harley, but it didn't sound like a weed whacker either ;-}

 

[mapbike]

SBP exhaust is the best universal set up I know of, offers good low to mid rpm performance.

With some mods it can be made to work better for high rpm power, I've run one in the stock form, I also have run it on one bike for a long time with the packing removed from the silencer, its only slightly louder this way and doesnt seem to make much difference in performance.

If you want to keep the noise level down and add a noticeable power increase over the stock muffler, the sickbikeparts expansion pipe is the best unless you have all the tools and ability to fabricate a custom exhaust.

 

[triride]

Hi,

Now received and fit new exhaust
Was a bit tricky trying to get correct position for it to sit nicely so it would not rub on legs whilst riding.
I will move to step 2 and fit/weld some permanent sections to where the silicone sections are at present.
Any tips for this next step?
I just need to buy the correct guage tubing, I already have a pipe bender and mig welder so can't wait to get started
The performance of the exhaust is slightly better than the stock one was but not drastically so I asume that is all I am going to get unless I fit a jackshift kit which I will in due course

Cheers, Pete.

 

[exokinetic]

If you are looking for more performance from the exhaust system, you can find it...


In a Dirtbike pipe. Basically any 2-stroke Dirtbike pipe in the 65-90cc range will give you IMPRESSIVE performance gains. The smaller CC pipes tend to produces more power at higher RPM's, where the bigger CC pipes tend to produce more power at lower RPM's. But make no mistake, all of them (Dirtbike pipes) will produce more performance, over a wider RPM range, than anything sold "for" the China Girl.


When it comes time to fit that Dirtbike pipe to your cylinder, don't look any farther than:

http://shop.crmachine.com/product.sc?productId=105&categoryId=21

One of the "Fire Breather Header Kits". They are hands down, the best way to mount a pipe to the China Girl engine.

 

[triride]

Thanks exokinetic, good info to work from!
I suppose the exhaust I bought - (SBP - ES02) is just a dirt bike copy modified to fit a china girl.
At the moment I have reverted back to the standard china girl stock exhaust until I get time to permanently fit the required steel sections instead of the rubber sections that come with the exhaust, which are a good idea as it enables you to fit the exhaust in a position that suits your personal requirement.