[spider_kyle]

This is really just a personal interest post, and if any one has any input, or maybe even has an answer, do not hesitate.

So, riddle me this... Why are the intake and exhaust manifolds orientated the way they are on motorcycles. To me, it would make sense to have the air enter the engine from the front, because it comes from the front. And it would also make sense to have the exhaust leave the engine from the rear, since it goes to the rear of the bike. As it stands, each of the intake/exhaust gasses wraps around the engine before entering it. My only real guess as to why this is, is because there is simpy no room for an airbox and carbs/injector bodies in front of the engine. But to me, this would seem like something worth looking into, especially with all the advancements modern motorcycles have. Straightening the intake and exhaust paths would result in less turbulance in the intake, and would even save power on the exhaust. I think moving the engine back could help create enough space in the front end, and as far as street bikes are concerned, the advantage gained by having the CG farther foreward isn't as important as in race bikes. Well, these are my thoughts for the day.

 

[knightslugger]

on most other modern sport motorcycles, air does enter from the front. you have to remember, this bike is over 20 years old. that carburetors just aren't designed for forced air intake anyway.

 

[illusion]

hmm, are there any modern bikes that have carbs in the front of the motor? (I think kyle just meant this, not ram-air.. well what do i know )

 

[bitzz]

The newest bike that I can think of that had the carbs in front was a '70s TZ250. It didn't work.

 

[MrSciTrek]

Here's 2 cents worth of thoughts...

Carb & filter(s) in front would make radiator placement trickier & leave both more susceptible to dirt, bugs, rain, spray... etc.

Exhaust in back would be shorter but would toast the battery unless it was moved... to?
Even then, the routing of the pipes would have to avoid legs & feet of rider & passenger.

 

[illusion]

good points now I begin to understand why things are like they are..

 

[spider_kyle]

Wow, that got a lot of responses really fast. And yeah, I was referring to having the carbs in front of the engine, not just a ram air system. I've never heard of it. As far as the rad orientation goes, I think it should be moved anyway. I like the idea of having it up under the tail as on the Honda NAS, and the exhaust should never run all the way to the back of the bike, it should be dropped onder the bike like Buell does it, (also on the NAS). Dropping the exhaust can makes as much sense as anything on a bike, lower center of gravity, and it pretty well hides all the pipes.

It really sounds like changing anything would require changing almost everything, which seems like too much of a change. But look at the Bimota Tesi, a bike that questions the traditional motorcycle (granted not regarding the engine in particular), and personally, I think it's only going to change more.

While I would never buy a Buell, cuz its a harley, I think they have brilliant engineers, and if you want to see what the next "innovations" are going to be in motorcycle engineering, look at what they already ahve on their bikes.

 

[maverick9611]

ya see spiderman it's like having your fortune told!!!

 

[fog]

Well nobody get a food pellet on this one. Heat folks Heat was the reason remember most bike were Air cooled and in front was the best place to get the most cooling air to the hottest parts of the engine. All the other stuff is true to an extent. but now in this day of modern tires and chassis design that needs the maximum amount of weight as far forward ans you can get it. The Exhaust Pipes tale up a lot less room too. Also as the engines get Laid down more a more to the Horizontal the intake tracts are virtually straight again. And besides in the exhaust are not a critical as the is much more pressure on the exhaust gasses.

FOG

 

[dragknee]

And besides in the exhaust are not a critical as the is much more pressure on the exhaust gasses.

???

i was with you until this sentence. besides what in the exhaust? its not as critical as the what is?

 

[knightslugger]

^ I'm with you Dragknee. Must be the pain killers.

 

[fog]

Yes the pain killers and a bit of senior moment.
The bending of the pipes in not as serious in an exhaust.

FOG

 

[knightslugger]

would you like some jack danials or some johnny walker with that vicodin? lol!

but i think i get you. all the bends in an exhaust system doesn't mean anything because there is so much pressure anyway.

da?

 

[Mad Matt]

Having the exhaust manifolds in front allows a stream of air to hit them and cool them nicely. This would be a lot harder to do packed up behind the engine and any trapped heat would cook things including the riders privates. Carbs are also easier to operate with some relatively static air pressure and the dynamics of high speed air over filters or intakes at various angles would actually lower the air pressure seen by the carb in some cases and thus rob power. A ram air box solves this somewhat but the carb would need a static line run to the box to equalize and operate properly.

Ducting air all around can make for an elegant looking bike but it increases weight, cost and complexity. Putting the radiator out in front is a pretty sure-fire way to get sufficient cooling air. Having it buried in a fairing requires a proper design so that the pressure at the outlet is higher than the inlet (usually the outlet is larger or has some bodywork to speed up the airflow across the exit vent) or the radiator and possibly the inlet duct will stall the cooling air. And it may all work great until you ride in a crosswind next to a truck and find out THAT particular condition rapidly overheats things.

Buell definitely has some forward thinking ideas but remember that Kawasaki has been building aircraft for years and so has a ton of experience with buried engine installations and aerodynamics. Whether this actually applies to the motorcycle division is probably debatable but the Kawi Motors certainly has a resource if they choose to cross pollinate. I think it comes down to where on the cost/complexity/performance curve you are and the Japanese bike builders have that pretty well optimized.

 

[fog]

Don't count too heavilly on any of Kawasakies aircraft experiences filtering down to the EX. They are built in the third celler (down) workshop by Nyfoie Jungkoro a 99 year old lifer that has never even seen an Aircraft;

FOG

 

[MrSciTrek]

Kawasaki aircraft site:

http://www.khi.co.jp/products/space/index.html

 

[Frog]

Don't count too heavilly on any of Kawasakies aircraft experiences filtering down to the EX. They are built in the third celler (down) workshop by Nyfoie Jungkoro a 99 year old lifer that has never even seen an Aircraft;

FOG

If I get you a paper and a pen, can you get me his autograph ?

 

[Guest]

Huh, you learn something new everyday. I had no idea Kawasaki made aircraft.

 

[MrSciTrek]

Huh, you learn something new everyday. I had no idea Kawasaki made aircraft.

Well if Yamaha can make car engines, concert guitars and pianos...

 

[spider_kyle]

Japanese companies make everything. And even though the EX is an old design, the geometry of manifolds has been mostly the same for a long time. I'm personally into all sorts of engineering advancements to solve problems. Overheating pipes is no problem if you cermic coat the inside of the pipes. Yes it's excessively expensive, but it's better than any other heat control treatment you can do. I'm big into innovation is all.