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Discussion Starter · #1 ·
Reassembling my '80 CM400T and plan on replacing exhaust. (old pipes dented, rusted, just plain ugly). I'm wondering if anyone can fill me in on pros/cons of converting from dual to two into one? Also, need a recommendation on where to buy exhaust system--4 into 1, Dime City, others?
 

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You're not going to find too many in the States besides Mac, but if you don't mind the shipping costs there are a few available in Europe... and the UK :grin:

Ok, scratch that. Apparently David Silver Spares is a Motad distributor for Canada and the US.

https://www.davidsilverspares.com/motad/
 

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Pro: you can lean the bike further toward the non-muffler side without scraping any chrome. Functionality wise, that's about it.

Aesthetically it boils down to personal preference.

Your CM400 (or any 400/450SOHC) has a power chamber.

https://www.hondatwins.net/forums/67-miscellaneous-discussion/41350-power-chambers-explained.html

Any exhaust you install which does not utilize that power chamber is going to require some tuning to accommodate the change. But then, any significant change will do the same. A series of plug chops after you get it all together can supply you with the information you'll need.

I'm sure some folks who have made the changes you're contemplating will be along to share their experiences.
 

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Discussion Starter · #4 ·
thanks JT and Alan F. Bought my bike used and guess the PO took off the power chamber, just two separates pipes and mufflers on it when I got it. Time to reconsider....
 

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When I got my CB400T, it had a 2 to 1 and I spent the $$ to go back to stock .. NO REGRETS. Took time to find the parts but well worth the effort
 

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The biggest issue with 2-1 systems is primary pipe length. The stock system utilizes the power chamber to extend the pipe length for low end power and the later versions of that unit are designed to give back the top end power at the same time.
I've compared the stock exhaust and a 2-1 system on the same bike over the same trip in the same weather. The stock system did enhance the low end driveability some but also reduced mid-range and top end power some. On the same exact hill, @3% grade, at 65 mph the stock system needed to be downshifted to 5th to accelerate while the 2-1 was able to remaining in 6th. No significant difference found in fuel mileage.
I've stuck with the 2-1. It started life as a Hooker Header exhaust but after doing the math I cut the pipes back a few inches, 2-3".
The MAC 2-1 system isn't worth the money, pipes too short and thin wall tubing used. The MOTAD system looks to be close to right but I don't know the primary pipe length. IIRC the pipes need to be @31.5", I'd have to find my notes or do the math all over again.
Here's some pictures of the Hooker exhaust on a CB400T1
T1b.jpg T1b-002.jpg

And here's my exhaust on a CM400T
189782_1684151258715_1085612076_31447377_5744962_n.jpg 201_5434.JPG 201_5435-001 (1).JPG
 
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