Odd build - Page 6

Megadan · 04-09-2018, 05:24 AM

Helmholtz resonators are often used on header pipes like that to help smooth out the power curve. Since the pressure waves of the exhaust travel at nearly the speed of sound (basically a fixed velocity), and the exhaust pipe is a fixed length, certain RPM ranges have imperfect harmonics which cause dips in power due to a loss in scavenging - meaning that the timing is the only variable. By adding a resonance chamber to the header pipe, it can help to decrease the intensity of the pressure waves, and smooth out the power curve. Not really meant for more power, but better overall power.

It is also often used on intake pipe systems to help eliminate "bad" resonance wave point and smooth out airflow. Or even simply used to reduce resonance noise.

Harmonics and Resonance waves are one of my weird hobbies lol.

In the case of this pipe, it may actually serve some benefit, but more than likely nothing to write home about. There are a lot of variables at play that can completely change the locations, size, shape, inlet area and length of the chamber, that unless it is specifically designed and built for a particular engine, with a particular cam profile, to a specific pipe length (Node and anode relationship) , and then desired affected RPM range, it is likely not going to do a whole lot of anything useful. It may alter the sound a bit though, which is possibly why it is there...or simply for looks.

Weldangrind · 04-09-2018, 11:14 AM

I really like the battery and solenoid relocation. I have a Chonda dirt bike build on the back burner, and I think I'll borrow your idea.

ChondaChondaChonda · 04-10-2018, 12:37 AM

Took a day trip out to test the mods out. Fabulous day of 50+ miles of mostly single track!! The new tank really makes the bike handle well. On steep climbs I can get my weight forward and it's much easier than it used to be.

Motor ran well. Have to get used to how low-end centric she is. Short shifting all day.

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BlackBike · 04-10-2018, 01:29 AM

No appologies dan

"Harmonics and Resonance waves are one of my weird hobbies lol."

I think I remember a few labs from college.

Physics is fun.

BlackBike · 04-10-2018, 01:31 AM

Good stuff CHONDA, I see your spring time in Idaho is coming along nicely.

Megadan · 04-10-2018, 04:18 AM

That tank looks really good on there. I think that NC250 spoiled you to high rpm power though. Welcome back to the grunty side of things.

ChondaChondaChonda · 04-10-2018, 11:04 AM

Yes Dan!! I had to re-learn how to short shift this bike!! Whole different animal.

Enjoy:

ChondaChondaChonda · 04-10-2018, 11:56 AM

Kind of gives an idea of the terrain we get into at times.

A brush with a tree knocked the camera angle down too far; it get better at the end.

04-09-2018, 05:24 AM	#76
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 7,889	Helmholtz resonators are often used on header pipes like that to help smooth out the power curve. Since the pressure waves of the exhaust travel at nearly the speed of sound (basically a fixed velocity), and the exhaust pipe is a fixed length, certain RPM ranges have imperfect harmonics which cause dips in power due to a loss in scavenging - meaning that the timing is the only variable. By adding a resonance chamber to the header pipe, it can help to decrease the intensity of the pressure waves, and smooth out the power curve. Not really meant for more power, but better overall power. It is also often used on intake pipe systems to help eliminate "bad" resonance wave point and smooth out airflow. Or even simply used to reduce resonance noise. Harmonics and Resonance waves are one of my weird hobbies lol. In the case of this pipe, it may actually serve some benefit, but more than likely nothing to write home about. There are a lot of variables at play that can completely change the locations, size, shape, inlet area and length of the chamber, that unless it is specifically designed and built for a particular engine, with a particular cam profile, to a specific pipe length (Node and anode relationship) , and then desired affected RPM range, it is likely not going to do a whole lot of anything useful. It may alter the sound a bit though, which is possibly why it is there...or simply for looks. __________________ 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2010 VFR1200F - http://chinariders.net/showthread.php?t=20708
	1

04-09-2018, 11:14 AM	#77
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I really like the battery and solenoid relocation. I have a Chonda dirt bike build on the back burner, and I think I'll borrow your idea. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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04-10-2018, 12:37 AM	#78
ChondaChondaChonda Join Date: Oct 2016 Posts: 547	Test ride day!! Took a day trip out to test the mods out. Fabulous day of 50+ miles of mostly single track!! The new tank really makes the bike handle well. On steep climbs I can get my weight forward and it's much easier than it used to be. Motor ran well. Have to get used to how low-end centric she is. Short shifting all day.
	2

04-10-2018, 01:29 AM	#79
BlackBike Join Date: Feb 2016 Location: George West, Texas Posts: 4,097	No appologies dan "Harmonics and Resonance waves are one of my weird hobbies lol." I think I remember a few labs from college. Physics is fun. __________________ ***************************************** 2015 Bashan"Blaze" BS250GY-31 (DB-07K-250) GONE 2017 Suzuki V Strom 650 XT "We are all born ignorant, but one must work hard to remain stupid." ~Benjamin Franklin~
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04-10-2018, 01:31 AM	#80
BlackBike Join Date: Feb 2016 Location: George West, Texas Posts: 4,097	Good stuff CHONDA, I see your spring time in Idaho is coming along nicely. __________________ ***************************************** 2015 Bashan"Blaze" BS250GY-31 (DB-07K-250) GONE 2017 Suzuki V Strom 650 XT "We are all born ignorant, but one must work hard to remain stupid." ~Benjamin Franklin~
	1

04-10-2018, 04:18 AM	#81
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 7,889	That tank looks really good on there. I think that NC250 spoiled you to high rpm power though. Welcome back to the grunty side of things. __________________ 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2010 VFR1200F - http://chinariders.net/showthread.php?t=20708
	2

04-10-2018, 11:04 AM	#82
ChondaChondaChonda Join Date: Oct 2016 Posts: 547	A little video from our day yesterday! Yes Dan!! I had to re-learn how to short shift this bike!! Whole different animal. Enjoy:
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04-10-2018, 11:56 AM	#83
ChondaChondaChonda Join Date: Oct 2016 Posts: 547	Another vid Kind of gives an idea of the terrain we get into at times. A brush with a tree knocked the camera angle down too far; it get better at the end.
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