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1975 CB200T custom exhaust help

V45Bo_510

New Member
Joined
Mar 9, 2023
Total Posts
7
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Location
San Leandro, CA, USA
Hey everyone I'm going to make a custom exhaust for my cb200T. I just have a few questions for the exhaust experts on here. First question is, what exhaust header pipe set up is better for performance, a 2-2 setup using 1 inch pipe, and I want the pipes to be way shorter plus I'm putting 15" goose-cut turn out mufflers on the end of both pipes? hopefully the exhaust will end just before the rear wheel. Or is a 2-1 setup better? If I do a 2-1 I'm thinking dual pipes off the cylinderhead being 3/4" pipes and have them come together right after they bend under the bike to a 1.25" or a 1.5" collector and then immediately into a single 15" goose cut muffler? What setup would work best? are the pipe diameters I mentioned good? or do you recommend a better size pipe to use?
 
This is a bit of a rabbit hole but I'll try and keep it basic.
The primary pipe ID should be the same size as the Exhaust valve diameter, this may be the same size as the exhaust port but I'm unsure of that. The pipe ID may end up being slightly larger due to the available pipe diameters but in any case should be no more than 1/8" larger, never ever smaller.
The pipe wall should be the thickest available as well, it retains the heat of the exhaust gasses for better flow.
Primary pipe length is determined by the bore, stroke and degrees of exhaust valve open. The length measurement starts at the valve stem, not the head mating surface. Technically you're supposed to measure from the actual valve seat farthest in to the top of the exhaust mounting flange, then measure from the valve seat outer to the bottom of the flange mating surface add together and divide by 2. My way is within range considering this is not a race engine.
Here's a source for the 2-1 collector https://www.coneeng.com/motorcycle_components.html
The muffler should be at least 10x the swept volume of 1 cylinder. 200cc/2 =100cc x 10 = 1000cc or 1 liter.
 
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