Upper exhaust much cooler than lower one

[kbosak]

Hi,
I have just bought Kymco Venox made around 2007. So far I have only 100km on it, being an owner since 8 weeks (2 rides).
Used for 11 years in northern Italy, some minor marks of sun on rear tire, scratches here or there, rusty exhaust pipe connector but works fine. This is my first motorcycle, I am 40 yrs old and have 15 years car driving experience. Bought from bike trading company in Poland. The bike runs very well and smooth for its age (has loud gear changes etc from car user perspective). Bike kilometrage is 26000.

Much to my surprise, I have found that exhaust from upper tube has much less pressure than from the lower one. Lower tube has slight discoloring (no serious discoloring on collectors) but upper tube has no discoloring and I can touch it with my hand for a split second after 40km city ride without getting burnt. It is only slightly hotter than engine body.

Does it means that:
-all Venoxes are like that?
-has anybody modified the exhaust (no signs of it)? Is it common to modify Venox exhaust like that?
-my Venox has only left saddlebag mounted. Somebody was aware the exhaust might get hot?

Is it dangerous in principle for engine lifespan? The motorcycle runs really fine, incl in very cold weather (like -10C).

I can make measurement of it but got no IR camera and weather is not yet compatible with city riding.

[CROSSBOLT]

Sounds like one muffler is plugged.

[Stig / Major Tom]

We need a Venox guy to jump in here ........but here is my best guess:

 I think the lupper pipe is a fake exhaust pipe, just like the fake giant cyclinder heads visible from the sides. I bet there is nothing coming out of that can because the exhaust is routed out the bottom can only.

It looks like a giant motorcycle engine, when it is not; and looks like it exhausts through big twin pipes, while it does not!

I got 50 cents on this one.

Really, they wouldn't have done that, would they?!
again....

Stig

[CROSSBOLT]

I will chime in, Stig, just so you won't be alone when the rocks fly! There is a surprising amount of fakery on that otherwise neat motorcycle. However, there seem to be two cylinder heads with two exhaust pipes. One pipe to each cylinder. This is according to a parts diagram and list. So I would conclude my original reply. But I had to, HAD TO CHECK! I still remember the guy that told me straight-faced that his Venox would go 165 mph! Only a Honda 250 cc Gran Prix race bike would do that!

[Stig / Major Tom]

I will chime in, Stig, just so you won't be alone when the rocks fly! There is a surprising amount of fakery on that otherwise neat motorcycle. However, there seem to be two cylinder heads with two exhaust pipes. One pipe to each cylinder. This is according to a parts diagram and list. So I would conclude my original reply. But I had to, HAD TO CHECK! I still remember the guy that told me straight-faced that his Venox would go 165 mph! Only a Honda 250 cc Gran Prix race bike would do that!

Wish I could have heard one of those with the engine running. Apparently it is pretty cool.
The dealer had one the first day I was looking at scooters 5 yrs ago next month. I got to poking around looking at the engine and had a good laugh.
Very interesting concept.
Yeah, I suspect an Italian squirrel might be living in that pipe.

Stig
Stig

[Hairy Bob]

Good morning guys. I was just sitting out the back of my place having a coffee on my day off, so I thought I'd drop in on the forum seeing that I've been very slack and not visited for a while. Regarding this exhaust issue that Osama has .. Yes, they are both "real" exhausts ( geez Stig    ), one from each cylinder, so they should both get damn hot, so there is something definitely amiss there. Maybe the upper muffler isn't connected properly Osama, or the muffler gasket is leaking or not there at all .. or you said the exhaust connection was rusty. What ever it is, you need to get it sorted mate, because if you haven't got the correct back pressure from the exhaust, you'll end up cooking your rear cylinder. I've attached a PDF of the exhaust from the parts manual so that you can see the whole set up. I hope this helps in some way.
Regards, Hairy Bob.

Hey there CrossBolt ... you're right on the money there mate about that guy who reckoned he got 165 mph out of his Venox ... he was dreaming. I rolled the pony out to 140 klm per hour once .. what's that, about NEARLY 90 mph !  It took a while to get there and that was absolutely ringing her neck !  As you said CrossBolt .. MAYBE on a tricked up two stroke G.P. bike, but no way on a 250 four stroke cruiser !
Ride safe guys.
Regards, Hairy Bob.   

[kbosak]

Thank you for the suggestions. It was an indication of unreliable wiring to one of the cylinders, which was not firing correctly. One day I rode on paved road and it died during moderate riding (the second cylinder could not keep the motor spinning below some 2000RPM). Local mechanic was surprised by mess+entanglement but fixed the problem. The problem didn't re-occured for the next 2 months.  Upper exhaust is still cooler than bottom one, but the difference is much much less than before. I was learning to drive and not sure what dynamic to expect, so I didn't raeliazed the problem at first place.