carb questions

[Toby woodman]

I am wanting to upgrade the exhaust on my motorised bike. I am not worried about noise so I am thinking about going for a banana style expansion chamber. would that make the engine run leaner, if so would I be better jetting up for good full throttle performance and tuning the rest of the rev range using the needle clip. would this avoid engine damage from running too lean. anyone who has upgraded their exhaust, did you have to jet the carb afterwards?

 

[ImpulseRocket]

I am wanting to upgrade the exhaust on my motorised bike. I am not worried about noise so I am thinking about going for a banana style expansion chamber. would that make the engine run leaner, if so would I be better jetting up for good full throttle performance and tuning the rest of the rev range using the needle clip. would this avoid engine damage from running too lean. anyone who has upgraded their exhaust, did you have to jet the carb afterwards?

Those banana pipes really aren't any better than the stock muffler. If you do want an expansion chamber at least consider an mz65 clone pipe. They are still affordable and will actually give a bit of a boost in power in the middle rpm range. https://www.amazon.com/Kinbelle-Exh...=1678298921&sprefix=mz65+cline,aps,348&sr=8-8

It will be loud though, so many people pair them with one of these mufflers, and they simply shove the exit pipe of the muffler inside the stinger on the clone pipe.

https://www.amazon.com/Universal-Motorcycle-Exhaust-Muffler-Silencer/dp/B07RWCJNL6/ref=mp_s_a_1_4?crid=QHBU8XNDYQ2L&keywords=2+stroke+muffler&qid=1678299096&sprefix=2+stroke+muffler%2Caps%2C263&sr=8-4

 

[Toby woodman]

would I need to adjust the carb to run this exhaust?

 

[ImpulseRocket]

would I need to adjust the carb to run this exhaust?

Possibly. The same with any mod like this.

 

[Toby woodman]

would I generally need to jet up or down with the main jet?

 

[ImpulseRocket]

I dislike jetting questions like that. "Generally" it would often require a step down in jet size...

BUT

Jetting should be adjusted based on what you see and observe for yourself after doing the exhaust. That is the proper answer. Why? No two engines and setups are alike.

 

[Chiron TL-34]

If you do want an expansion chamber at least consider an mz65 clone pipe. They are still affordable and will actually give a bit of a boost in power in the middle rpm range. https://www.amazon.com/Kinbelle-Exhaust-Muffler-Stroke-Engine/dp/B07RR6Z7D8/ref=mp_s_a_1_8?crid=2FKII1EAQDXFT&keywords=mz65+clone+exhaust&qid=1678298921&sprefix=mz65+cline,aps,348&sr=8-8

Do those kinds of mz65 clones take off a little power from high end?

 

[ImpulseRocket]

Do those kinds of mz65 clones take off a little power from high end?

Probably, but the header length is almost perfect for the low and mid rpm power that most people ride in.