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Discussion Starter #1 (Edited)
I was getting ready to put the dust cover on after I finished riding and lightly felt the rear exhaust muffler to make sure it wasn't too hot. Just warm, OK. On impulse, I felt the front pipe and was still pretty hot. The next day, I took a ride around the block a couple of times and checked with the temperature sensor. The front pipe near the cylinder was 230 degrees F. The rear pipe same place was 90 degrees F. No, I haven't lost my mind already! The bike is perfectly tuned, adjusted, new synthetic oil, running perfectly, and making no unusual noises. Single carb and the engine and exhaust are stock. Any comments or theories?

2009 Yamaha Virago 250, 5000 mi. and well maintained.
 

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Discussion Starter #3
No, the back pipe just runs down normally to the muffler. The only thing is that crossover pipe/reservoir affair. The crossover pipe(1") runs from the forward end of the front cylinder muffler to the pipe connection into the rear cylinder. The reservoir is a flat container about 5"x5"x1" that sits directly under the mufflers. I don't know this type of system or exactly what it's purpose is. If someone else could possible measure the temp on their bike for a back-up check it would be very helpful. Many multimeters come with a temp sensor probe now. That is what I used. Thanks, Wavelength.

2009 Yamaha Virago 250, 5000mi.
 

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So what is the temp of head pipe? That's really the only temp that's important on a motorcycle IMO.

Like you said, if exhaust gas is running through different contraptions....that is probably the reason for the temp difference at the muffler. If you had straight pipes on there, they would be close to the same temp at the ends.
 

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Discussion Starter #5 (Edited)

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looks like to me part 12 is a dummy pipe (note no exhaust gasket). part 9 looks to be the real pipe feeding the main muffler assembly (part 1) which then flows from the lower muffler and come out of the top muffler at the same time.

yes I know its an old thread.
 

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Right, as far as I know the pipe coming out of the rear cylinder IS NOT where the exhaust actually comes out. It's just there for show. It really exits out the bottom or something. Weird.
 

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Discussion Starter #8
Exhaust

Yea, As far as I can tell without an internal view, the flat reservoir-looking piece between the mufflers must equalize the pressure between the two. Piece 9 and 12 join together at the top of the rear cylinder in a common fitting(not shown). This looks like some #1 cylinder exhaust is fed to #2 cylinder exhaust via part 9. I think that sometimes exhaust pressure/vacuum can be used as a pump for positive crankcase ventilation, but I am not up on the theory of this.
 

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Can confirm what others are saying. The rear cylinder exhaust pipe (the chrome one) is a dummy pipe until it passes the catalytic converter (not sure if it's called this on a bike but it's function is the same) which is under the bottom pipe that connects to the front cylinder. This is why Yamaha is clear to say that it's not a dual exhaust, but rather a dual exhaust pipe system since technically, exhaust comes out both.

Josh

2014 V-Star 250
 

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You're welcome! They're great bikes, so if they added a little extra chrome to make it stand out I'm ok with that! BTW, have you done any sprocket swaps? I just changed my front sprocket to a 17 tooth from the stock 16 tooth, and what a difference it makes. It's as if I'm riding a whole new bike.
 

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Discussion Starter #12
Exhaust

Yea, I'm riding with a 17/40 ratio now and am pleased with it. I live in Florida, so everything is pretty flat. Still have the stock 16/45 in case I want to ride in the hills sometime. The extra chrome is fine with me too, I like the look. I like the bike too though the gears seem a little whiney. I took it to the Yamaha mechanic and he told me there's nothing wrong, just the way it sounds.
 

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I, too, have a 2009 250 Star (nee Virago). The salesman at the bike dealership was surprised when I showed him that the chrome bit on the rear cylinder was NOT the real exhaust pipe. I strongly suspect the front pipe conceals a small diameter pipe of the same size as the rear pipe, but I don't plan to take it apart to look. Both pipes route into that box under the bike, which then routes to the two shiny pipes. I believe that would be called a two-into-one-into-two exhaust. If you actually go look under most bikes with factory exhaust systems you will find similar arrangements. The factories go to great lengths to make their V-twin exhausts look like two independent pipes.
 

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Discussion Starter #14
Exhaust

Yes, Good point. There could be a small pipe in the big one. In fact, before, I was wondering how the imbalance in exhaust pressure could be right. I didn't see it on the parts diagram, but it could all be shown as one assembly. The flat part under the two mufflers someone said was the electrolytic converter and that sounds right.
 
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