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I have an after market collector box on my custom which doesn't seem to fit that well hence I am always having to mess with it to maintain a seal. Does the team think I should
replace with the genuine article, or
chuck the part and use pipe to bridge the gap between front pipes and Silencers. I am concidering replacing the silencers with a pair of Harleys I have in my spares bucket. Ideas pro's and cons please
 

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Ditch the box and just use a pipe to connect the two sides. Combined with the Harley muffs it should sound sweet. May need to rejet though, as it'll likely lower the backpressure a bit.
 

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make it fit i am not a fan of playing the guessing game of which jets to use.....
 

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So the H box is not needed, it is just there to balance the backpressure? I am guessing it is not a good idea to run independent exhausts on each side without joining them somehow, correct?
 

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So the H box is not needed, it is just there to balance the backpressure? I am guessing it is not a good idea to run independent exhausts on each side without joining them somehow, correct?


Most twins run best with a crossover of some type, so yes there should be a balance tube to help scavaging of the exhaust gases.

My vote is to make them look good, sound good, and be solid on the bike. Whatever that is to you? The Harley option is probably the best as you already own them and they're are a proven replacement for many of the guys on this board. We put a set on my Dad's CX 500 and they worked out great. Some people make a hobby out of teasing H-D but their chrome is second to none. They also sound nice on a CX. Two cents.

Cheers, 50gary
 

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I just purchased a Mac 2>1 header for mine, it has a great sound and does increase the power a bit. Cost about 300, but I think it was worth it. I haven't had any jet issues as of yet, but spring is still a little ways off.



Most twins run best with a crossover of some type, so yes there should be a balance tube to help scavaging of the exhaust gases.

My vote is to make them look good, sound good, and be solid on the bike. Whatever that is to you? The Harley option is probably the best as you already own them and they're are a proven replacement for many of the guys on this board. We put a set on my Dad's CX 500 and they worked out great. Some people make a hobby out of teasing H-D but their chrome is second to none. They also sound nice on a CX. Two cents.

Cheers, 50gary
 

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when in doubt a sawzall and a welder are your best friends. make it fit. then it will be "custom"
 

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If you use the harley exhaust, and you are not using the H-Box, how do you piece them together with the stock headers. Is there another header you can use to make is look like more clean?
 

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If you use the harley exhaust, and you are not using the H-Box, how do you piece them together with the stock headers. Is there another header you can use to make is look like more clean?


When I purchased a 1980 CX500D project, the H-Box was in terrible condition. Had a local

muffler shop to make connector pipes out of aluminum/steel pipe from the headers to the HD mufflers. Ready to experiment with the jetting to see "if" I can come up with the right

combination for the proper mixture with pod air filters. Will see how it works out. Here

are some photos taken tonight. Currently have the right side removed to apply permatex

muffler & tailpipe sealer to the joints and will do the same to the left side.







 

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Thanks for the reply. That looks pretty good. Okay, a couple of questions for you. Where did you get the clamps? How is your bike running without the H Box currently? Are you going to have your pipes that were fabricated by the muffler shop chromed?



I'm hearing all types configurations on rejetting the carbs. What configuration are you going to start with?



I just bought my CX 500 off ebay and I'm gathering information before I get started.



Thanks
 

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Thanks for the reply. That looks pretty good. Okay, a couple of questions for you. Where did you get the clamps? How is your bike running without the H Box currently? Are you going to have your pipes that were fabricated by the muffler shop chromed?



I'm hearing all types configurations on rejetting the carbs. What configuration are you going to start with?



I just bought my CX 500 off ebay and I'm gathering information before I get started.



Thanks




When I got my bike 7 ish years ago it had semi rusted off Mac slip on mufflers. They were similar to the pieces he had bent up only welded to the muffler and chromed and the jets that came out of the carbs were 90/120. And that was jetting from 1984.



Yes he will have to rejet. The question is always how much and what type of performance. Some can get away with doing nothing and just scooting around town. But if you want to do it right you're going to have to try several configurations. I'm pretty sure 90/120 will get you close. Right now with the 2 into 1 i'm down to 87.5/120. The small end doesn't seem to need to move as much and still perform.
 

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Thanks for the info. I was thinking of keeping the stock air breather. Do I still need to rejet and if so will the 90/120 configuration still work?
 

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Keep the air box and that combination should work for starters. Fine tuning may be needed. When the airbox is removed the jet combination goes even higher. Some have even used up to 135's. But you want the airbox.
 

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Thanks for the reply. That looks pretty good. Okay, a couple of questions for you. Where did you get the clamps? How is your bike running without the H Box currently?



I'm hearing all types configurations on rejetting the carbs. What configuration are you going to start with?



Thanks


Purchased chrome clamps from JC Whitney. The connector pipes are made out of a

aluminum/steel mixture and can be polished. Had to take the bike on a trailer

to the muffler shop for them to fit the connector pipes. Will not look like chrome,

but should look OK. It runs OK locally, but will not ride twistys with it until rejetted to

90/120, like BlindStitch recommends. When I purchased this bike it did not have mufflers

and the H-Box was in terrible shape. I removed the air box and installed a tray for the

battery & regulator/rectifier where the air box was located. Running pod air filters. Here

is a low quality video of the bike running with HD mufflers & connector pipes:



 

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I purchased a two in one Mac system from Old Bike Barn and put on my 80 CX500D. I didn't like the sound,so I put a sportster muffler on it.No rejetting as of yet. AGB-1
 

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I like the HD muffler sound on the CX500.



Will order K&N pod air filters # RC 2340 to replace the EMGO pod air filters. My thinking is,

probably need to rejet with the pod air filters/HD mufflers combination without H-Box.



Would be neat to test with Exhaust Gas Temperature sensors to really know where the mixture

is at while running during high power situations on twistys.



http://www.foxvalleykart.com/egt.html
 

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Wow! That sounds awesome! I like it! Thanks for the advise. I got my 78 CX off ebay about a month ago and I can't wait to dig into it. I plan on tackling the carbs first. I want to get it running good before I start my modifications.
 
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