top exhaust doesnt heat up?!

5:12

5:12

Well-known member
hello forumites,

i'll go straight to my question/issue. after about 3 hours of riding, i noticed that the top exhaust (stock)didn't even get hot (see pic attached, highlighted in yellow). the bottom one is extremely hot, even burnt my thumb on it. the top one is a little warm, a little bit warmer at the actual opening end, but to say the least, i can put my whole hand flat to the exhaust for an extended period of time and not get burnt. now, i say warm because it is just actually warm.

is this normal?! im thinking not. the rear engine block in which the top exhaust is connected to is hot, i would say almost the same temperature as the front engine block. air comes out of both exhaust. it's a 1990 yamaha virago xv250.

thanks in advance.

Capture.JPG
 
Which finger/s did you use to test the front/rear engine block temperatures?
 
ShaqX7 said:
Which finger/s did you use to test the front/rear engine block temperatures?
Click to expand...

?!?! does it matter? touched them multiple times with different set of finger(s). right hand. touched both left and right side of the blocks and the fins. my right thumb is still burnt from the bottom exhaust.

a friend also checked the temperatures of the exhausts and the blocks and confirmed.
 
What kind of bike is it? Im not a cruzer guy but I know that alot of the pipes like the one in your picture that are close to where you leg goes while riding, have heat shields so you cant burn your leg on them...Are you sure you weren't feeling a heat shield that is covering the actual exhaust pipe.?
 
The problem is your fingers aren't the correct body part to use... You need to test it again with something more sensitive.
 
it's a virago 250.

bike didn't feel underpowered. both exhausts are blowing about the same air pressure when i put my hand at the ends.

there's no heat shields on the pipes.

and regarding the touch test, the pipes and blocks were plenty hot. very noticeable temperature difference and i wouldnt want to touch it with something more sensitive. got one thumb burnt/blistered already.
 
Ok, I'm going out on a limb here...your rear cylinder isn't firing.
It will still "blow about the same pressure" because an engine is basically a big air pump.

You probably have no fuel getting to that cylinder.

You said that cylinder is hot? If it is hot, and the exhaust isn't...then where are the hot gases going?

Strange problem, man....
 
Spiider said:
Ok, I'm going out on a limb here...your rear cylinder isn't firing.
It will still "blow about the same pressure" because an engine is basically a big air pump.

You probably have no fuel getting to that cylinder.

You said that cylinder is hot? If it is hot, and the exhaust isn't...then where are the hot gases going?

Strange problem, man....
Click to expand...

I seriously doubt that he wouldn't notice one (of two) cylinders wasn't firing.

Maybe the front cylinder is getting less fuel for whatever reason and is running lean.
 
In my previous experiences with old air cooled V-twins is that the rear cylinder runs a fair bit hotter than the front because of air flow issues.
I am going to go with Spiider on this one and say your rear cylinder is not firing. The reason its feels roughly as warm as the other is just simple heat transfer.
 
Have you guys ever been in the same vicinity as a v-twin motor running on one cylinder?
 
It is only a 250, the different harmonics from the missing power stroke could be very subtle.

It might also be an ignition problem, considering he also seems to have a charging/starting problem. Could be related.
 
It's a Virago 250, the upper exhaust is decorative only. Take a close look at the rear cylinder head. You'll see a black pipe snaking it's way under the engine and into a box behind the crank case.

Y03XV250R10.jpg


Check out this website for parts numbers and exploded diagrams:
http://partsfinder.onlinemicrofiche.com/yamahagenuineparts/Yamaha_OEM/YamahaMC.asp

And here's a link to the Factory repair manual:
http://alpha.redeemer.ca/~cknowles/cycle/

For more technical help with your Virago, the Virago Tech forum should be your first stop. :)

I hope this helps solve a mystery and allows you to ride without worries!

Chris
 
Last edited:
what a waste of weight, lol
 
Wow good call there buddy. I was going to say keep it simple that makes it real simple !! Another problem solved from a gtam emeber
cknowles said:
It's a Virago 250, the upper exhaust is decorative only. Take a close look at the rear cylinder head. You'll see a black pipe snaking it's way under the engine and into a box behind the crank case.

Y03XV250R10.jpg


Check out this website for parts numbers and exploded diagrams:
http://partsfinder.onlinemicrofiche.com/yamahagenuineparts/Yamaha_OEM/YamahaMC.asp

And here's a link to the Factory repair manual:
http://alpha.redeemer.ca/~cknowles/cycle/

For more technical help with your Virago, the Virago Tech forum should be your first stop. :)

I hope this helps solve a mystery and allows you to ride without worries!

Chris
Click to expand...
 
You know, to be fair..it looks like the lower muffler is attached to the upper muffler allowing some flow. Maybe the top exhaust is actually somewhat functional, but only as a secondary chamber to the main pipe below. It would appear that the rear cylinder does not exit directly into the top muffler..but it might be partially used.
 
I have noticed a small amount of exhaust from the upper pipe on my 250 as well so I suspect there is a connection. The forward pipe is purely cosmetic.
Most Yamaha v-twin exhausts are 2-into-1-into-2 design with minor variations.
 
You must log in or register to reply here.

Back
Top Bottom