Exhaust and jetting
 

I would like to add exhaust and maybe a jet kit I don't know much about jetting a carb I have always played with fuel injection other than a built banshee but I had a local shop build most of it for me. I have read different places about modifying the stock pipe has anyone tried this and if so how was the results

Thanks for starting a new thread on this subject, Fisher. :) I'm sure many forum members are interested in this topic.

Please remind us; what bike do you own? I installed an FMF Universal Spark Arrestor on my Zong, and I like it a lot. :) However, if you exhaust header has a large bend in it, you might have problems mounting this muffler. ;)

Adding a free flowing exhaust, or removing the catalytic converter (if present) will definitely improve your engine's power. :) You will need to rejet your carburetor after an exhaust change, but this is not difficult. Show us photos of your carburetor, and we can help you purchase the individual jets you will need. :)

Spud :)

2007 gy200-5 I have it in my sig but it doesn't seem to be showing up

generally a more free flowing exhaust will make it run richer, which for a stock gy-5 is a good thing

Let's see a photograph of your exhaust header. If it doesn't bend too much at the rear, you might be able to install an FMF TC2 silencer, as shown in the following thread. ;)

http://chinariders.net/modules.php?n...ewtopic&t=8587

http://i442.photobucket.com/albums/q...ngScout088.jpg

Spud :)

I don't know if that is the picture angle you need or not

That's a good photo, but I would like to see more. ;) Does your exhaust header go in a straight line to the muffler? Can you remove the right side plastic, and post several photographs of the exhaust header and its junction with the muffler?

Spud :)

It bends around the cylinder head and then straight back to the muffler... I will get some pictures posted

The battery box and frame make using the existing pipe pretty complicated for the kind of silencer Spud used on his zong. The gy-5 would probably require some custom piping. It comes apart just in front of the bolt at the frame above the brake lever but at that point it is running almost level with the ground.

The usual work around for the gy-5 is to drill a 3/8th or 1/2" hole or 2 in the end of the muffler. It gets is flowing nicely and doesn't make much louder.

The usual jet for the stock carb is about 110 depending on your altitude, I had good success with a 107.5 in eastern Ks at around 900ft and I believe Spud left his stock as he is pretty high most of the time(I couldn't help it Spud) seriously he lives and rides mountains over 5000ft.

If the pipe is straight from the muffler to the exhaust header, there's a good chance you can install the FMF Universal Spark Arrestor. ;) This FMF silencer comes with a stainless steel midpipe which occupies the space between the silencer and the exhaust header. You don't need to use the existing mount at the front of the stock muffler. ;) The FMF silencer is light enough to be supported by the muffler hanger and the bolts connecting the exhaust header to the cylinder. :) Of course, you might need to trim the midpipe, modify the muffler hanger, et cetera, to install the FMF silencer, since it was not designed specifically for your Chinese motorcycle. ;)

Spud :)

I actually got to see a universal fmf this evening I am sure it will work so now what size jets should I order

If you're using a 30mm Mikuni, start with a 110 main and a 25 slow jet. The 30mm Mikuni comes with a 100 and 20, neither of which will feed the motor.

I recommend you buy the FMF Universal Spark Arrestor from the following vendor. ;)

http://www.oemcycle.com/Item/product/900012505

Measure the outside diameter of your exhaust header; it's probaby 1-1/4 inches in diameter. If that is true, you want the FMF 020303 silencer. ;)

Spud :)

After laying the bike down on a gravel road today and some rough hill climbs I started hearing a "ringing" noise in the exhaust curiosity got the best of me when I got home so I cut the end cap off the muffler and found that part of the muffler tip had broke off and was rolling around in there.... Ok now to the question part I actually like the look and sound of the modded exhaust but now it seems to bog or lag off idle and at low rpms I am thinking about doing the cclip mod any suggestions on which notch I should try