RX3 Visits With the X-300

pyoungbl · 03-25-2017, 08:07 PM

Building a motorcycle one has to think about where that engine will live, relative to the wheelbase. In most cases you want the weight to be distributed 50/50 front to rear. If you put the intake on the front that means you have to position the bulk of the engine farther back so the intake tract (fuel injection, air box, etc) do not hit the front wheel. Most manufacturers opt to put the exhaust side fwd and intake aft so it is easier to package everything. Maybe BMW has figured a way to make this work, time will tell.

Peter Y.

jbfla · 03-25-2017, 08:10 PM

Quote:

Originally Posted by pyoungbl

?....... Most manufacturers opt to put the exhaust side fwd and intake aft so it is easier to package everything. I recall someone reversing that recently but cannot remember exactly who nor how that worked out.

Peter Y.

New BMW 310 R/GS has intake in front, exhaust in back.

jb

Sullybiker · 03-25-2017, 08:26 PM

I've got nearly 15k miles on a Ninja 300, I know that mill pretty well.

I will say that exhaust is utter dogshit, and it traps a lot of moisture under that heatshield which is particularly annoying for the midpipe clamp, which corrodes fast. There's a lot of aftermarket solutions, though, most are stainless.

300 is not known for great fueling below 6k, I'm guessing they've tuned this bike accordingly as I had to get a fuel controller to sort mine out.

I think 39HP is very optimistic, although I do note those header pipes look a lot less restrictive than the Ninja 300. Conventional wisdom says that an aftermarket exhaust system and tune on the 300 is worth about 5-7hp.

pete · 03-25-2017, 09:11 PM

Quote:

Originally Posted by Biker_Andy

Why do almost all motorcycle engines have exhaust that exits on the front and intake on the back?

To me it makes more sense to have intake on the front (ram air potential) and exhaust exit at the back of a 4-stroke. Exhaust on the back would probably be better for air cooled engines as well. Plus exhaust systems could be made shorter therfore bikes could be made cheaper.

It would be a mess if you tried to fit a 2-stroke exhaust behind an engine.

Quote:

Originally Posted by MDStroup

I have had the same thought. I guess since they have been making them that way for so long that it would be pretty expensive to design and retool for such a bike.

Quote:

Originally Posted by pyoungbl

Building a motorcycle one has to think about where that engine will live, relative to the wheelbase. In most cases you want the weight to be distributed 50/50 front to rear. If you put the intake on the front that means you have to position the bulk of the engine farther back so the intake tract (fuel injection, air box, etc) do not hit the front wheel. Most manufacturers opt to put the exhaust side fwd and intake aft so it is easier to package everything. Maybe BMW has figured a way to make this work, time will tell.

Peter Y.

So I take it none of you fella's have seen the yamaha YZF/WR250 thats been around for a couple years now....

google is your freind...

..

Sullybiker · 03-25-2017, 10:18 PM

Quote:

Originally Posted by pete

So I take it none of you fella's have seen the yamaha YZF/WR250 thats been around for a couple years now....

google is your freind...

..

The WR250? Header at the front, intake at the back, isn't it? Unless I'm misunderstanding.

pete · 03-26-2017, 12:05 AM

Quote:

Originally Posted by Sullybiker

The WR250? Header at the front, intake at the back, isn't it? Unless I'm misunderstanding.

barrel leans backwards 10*... intake at the front.... exhaust at the back... fuel tank under the seat...

Jay In Milpitas · 03-26-2017, 09:03 AM

Quote:

Originally Posted by pete

barrel leans backwards 10*... intake at the front.... exhaust at the back... fuel tank under the seat...

NZ version might be different. The USA models still have forward exhausts, at least according to Google.

pete · 03-28-2017, 01:15 AM

Quote:

Originally Posted by Jay In Milpitas

NZ version might be different. The USA models still have forward exhausts, at least according to Google.

I realy don't think our market is big enough for it's own special model...
I will help yer out...

http://www.motorcyclistonline.com/fi...f-road-updates

http://www.cycleworld.com/2015/10/22...specifications

.

03-25-2017, 08:07 PM	#1
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	Building a motorcycle one has to think about where that engine will live, relative to the wheelbase. In most cases you want the weight to be distributed 50/50 front to rear. If you put the intake on the front that means you have to position the bulk of the engine farther back so the intake tract (fuel injection, air box, etc) do not hit the front wheel. Most manufacturers opt to put the exhaust side fwd and intake aft so it is easier to package everything. Maybe BMW has figured a way to make this work, time will tell. Peter Y.
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03-25-2017, 08:26 PM	#3
Sullybiker Join Date: Dec 2016 Location: Western PA Posts: 363	I've got nearly 15k miles on a Ninja 300, I know that mill pretty well. I will say that exhaust is utter dogshit, and it traps a lot of moisture under that heatshield which is particularly annoying for the midpipe clamp, which corrodes fast. There's a lot of aftermarket solutions, though, most are stainless. 300 is not known for great fueling below 6k, I'm guessing they've tuned this bike accordingly as I had to get a fuel controller to sort mine out. I think 39HP is very optimistic, although I do note those header pipes look a lot less restrictive than the Ninja 300. Conventional wisdom says that an aftermarket exhaust system and tune on the 300 is worth about 5-7hp.
	0