Fake? It is a twin, correct?

 

Yep. V twin. A side view shows a pipe from the front going down to the muffler and a pipe from the rear also going down, as is normal.

Closer inspection however, and it'll take a close inspection, shows that the rear "pipe" doesn't even contact the head. Its a fake. The real exhaust pipe from the rear cylinder is a small pipe going directly down, hidden from view by the outside world. It connects up with the goats belly (or whatever Star calls it) that then connects into the rear cylinder's muffler. You can hold the visible rear exhaust pipe with you hands all day long while its running and it'll never heat up because the exhaust gases never flow inside it.

So from the rear, you do have exhaust coming from both pipes.

I just wonder why this setup when it'd be just as easy to actually have the rear pipe act just as the front pipe.

 

...You can hold the visible rear exhaust pipe with you hands all day long while its running and it'll never heat up because the exhaust gases never flow inside it.

So from the rear, you do have exhaust coming from both pipes.
...

I had to google this, it came up several years ago and I still cant figure out whats what

your two statements are conflicting

if exhaust is coming out the two rear pipes, they must both get hot

earlier discussions stated the 2 cylinders combine into one muffler "box thing" which then goes out both rear pipes.

I dont know why they would try to hide a 2 into 1 exhaust setup - there are many bikes with multiple cylinders into one muffler, there are trades-offs from doing independent mufflers for each cylinder vs a combined muffler.

 

As seen here it looks normal. But in the second picture the pencil is touching a bracket that secures the end of the pipe. You can't see more detail in the picture but sticking your nose up close to the thing its obvious that the pipe ends there. It doesn't complete its journey to the head.

 

Allow me attempt to clarify any confusing statements I may have made. In the picture you see a standard looking setup of two exhaust pipes coming from the cylinders of a V-twin motor.

As we know the pipes that you actually see are normally just covers for the real exhaust pipe (or tube) that resides within.

The forward pipe that you see here is like that, a fully functioning "exhaust pipe". It gets hot when the motor is running because the actual exhaust tube inside gets hot as all get-go. Fine.

The rear pipe that you see does not even touch the head. It is completely hollow inside with no exhaust gases flowing through it. It is there for decoration only.

The rear cylinder actual exhaust tube that really exhausts the gases, is almost entirely hidden. From the rear head exhaust port, the bare tube then drops vertically down until it hooks into the goat's belly which then goes into the upper muffler corresponding to the rear cylinder muffler.

If you touch the rear cylinder pipe when it is running, it'll be cold because there is nothing in it. The rear cylinder muffler, however, will be hot as gases do pass through it.

Did this clear up any confusion?

 

I had the bike easily 10 years before I found this out. I found it out when looking at a website for aftermarket exhausts for this bike (don't remember their name now) and in that website it mentioned the fake exhaust. I had to go out in the garage to verify it and sure enough, they were right.

Boy did I feel like a dummy for not knowing that all of those years.

 

they have been putting the outer heat shield on MC exhaust pipes for many years now - it use to be just a chromed steel pipe coming right off the heads, and if you touched it with your arm or bare leg you got a nice football shaped burn scar.

On the 250 it looks like they could not get the heat shield and the inner exhaust pipe in the space together, so they ran the 'inner' pipe completely away from the shield.

Im sure there is an engineering story behind this at yamaha.

 

Oh I agree. There's a reason for it. I'm just not sure what it would be and was curious to see if this was a point of conversation along the way where someone knew the answer.

 

Wow just found this...it actually looks like it was set up to be a 2 to 1, with the look of 2 to 2. I've saw a video of someone cutting it down and attaching it to the top muffler and turning it into a 2-2. Strange!!

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It looks like they made it WAY more complicated than it should be !
OK now I see what you mean by fake pipe. At least you can't burn your leg on it.
I'm sure the engineers have a good reason , at least good enough to get it by the accountants .

 

That picture pretty much proves that a picture is worth a thousand words! I agree that it seems to be more complicated than necessary. Too bad I can't find someone that was in the design loop to explain why.

Thank you very much for finding that pic!!

 

No problem [emoji106]

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Just my thoughts on why Yamaha did this---Heat, My 250 Both pipes are live and that one gets very hot, Leg burn, most likely for the comfort of the rear passenger.

 

not heat

Looks
to maintain the classic v twin look, when the plumbing itself wasn't efficiently feasible.
Otherwise they could have just stayed with the 2 into 1 design and called it a day.
But then it does not resemble the bikes it was styled after.

If both your pipes are live up top, you have modified/aftermarket pipes.
The mufflers themselves though are both live on the OEM pipes, they have a weird combined inlet and crossover
chamber that looks a little funky when cut open
It's rather odd, but it's whatever the engineers determined gave optimal operation under the factory required parameters
which is a combo of performance, EPA reqs, various world transportation dept reqs etc.

400 650 950 1100 all have same preliminary pipe arrangement, which is physically what the 250 only is visually
and those put more heat out there than the 250.

Rider is the one sitting on it, not the passenger.
Don't wear shorts and rider be fine