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== Exhaust ==
 
== Exhaust ==
There are no bolt-on pipes for Jawa. At this point, two things have been done with some success. First off, one can remove the stock baffle and open up some new passages to improve flow. This is of course cheap and keeps the bike looking stock. More recently, people have been getting Biturbo pipes welded to stock headers. This typically gives a significant speed increase and if a second-hand pipe is used, the setup can be extremely affordable.
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There are no bolt-on pipes for Jawa. At this point, two things have been done with some success. First off, one can remove the stock baffle and open up some new passages to improve flow. This is of course cheap and keeps the bike looking stock. Typically 3-4 1/4" holes are drilled into the stock baffle, equally spaced and oriented around the original opening.
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Additionally, one can use the Tomos two-piece BiTurbo and a copper reducer fitting, 1''-1/2'' diameter, from a hardware store to mount the new muffler to the existing stock header on a stock 207 type Jawa.  The original header will need to be trimmed some, but care must be used to not cut too much so that the muffler doesn't hits the pedals.  If one heats up the header with a torch and grind the copper fitting so that it is flared slightly, the copper fitting can be tapped in with a mallet and will produce an interference fit.  Additionally, copper expands more than steel when heated, so the fit will tighten when heated together.  Then simply tighten down the muffler to the 1'' copper fitting with the supplied bracket.  One will need to create some sort of method to secure the muffler to the bike, but this won't be too difficult.  This can all be done without any welding and simple hand toolsSome models may vary from others, it is recommended to take the stock header and the header that comes with the BiTurbo kit to test fit potential fittings.
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One can use the Tomos two-piece BiTurbo and a copper reducer fitting, 1''-1/2'' diameter, from a hardware store to mount the new muffler to the existing stock header on a stock 207 type Jawa.  The original header will need to be trimmed some, but care must be used to not cut too much so that the muffler doesn't hits the pedals.  If one heats up the header with a torch and grind the copper fitting so that it is flared slightly, the copper fitting can be tapped in with a mallet and will produce an interference fit.  Additionally, copper expands more than steel when heated, so the fit will tighten when heated together.  Then simply tighten down the muffler to the 1'' copper fitting with the supplied bracket.
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Of course, almost any performance exhaust can be forced to workThe most common issue is mounting the exhaust to the frame.  Stock Jawa exhausts mount beneath the muffler while most mopeds mount above.  "Straight" exhausts such as the Techno Boss can simply be flipped upside down but angled and non-symmetrical exhausts (such as the BiTurbo and Techno Estoril, respectively) require the stock mounting bracket to be modified.  This can be as simple as using steel mending braces (available at any hardware store) or as complicated as relocating the stock mount.
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The stock exhaust mount was not designed to carry the weight of larger performance exhausts (most noteably the Techno Estoril) and will flex under stressThis problem can be solved by either strengthing the stock mount or adding an additional brace to divide the load.
    
== Porting ==
 
== Porting ==
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