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Discussion Starter #1
Just for fun, I removed the two large fairings, the front fender, and the passenger grabs. I noticed the bike has a lot more pick up as a result. Does anyone have any experience with this? How much is the fuel efficiency going to suffer without the fairings? It's basically like driving a wall down the highway. It's gotta have some impact.


nick
 

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If fuel efficiency suffers, it shouldn't feel like it has more pickup. Likewise, if it feels faster, it shouldn't feel like a wall driving down the highway. My guess is you may lose a few MPG's. I like the wind protection they offer so I never removed them.
 

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Yeah, I don't think you're really experiencing a true increase in acceleration, certainly not if you say it feels like driving a wall down the highway... that's a contradiction in terms.

There is no doubt that a CBR250R (or for that matter, any sport bike) without its body work will have a higher drag coefficient than the same bike with all its body work in place.

On top of that, CBR250R's without side cowls look like crap, IMO.
 

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i think the "pickup" is just in your head. both fairings and the fender together are probably under a pound, and the grab handles cant be more than a few. when it comes to sport bikes every ounce counts, but in this case the weight savings is so minimal that it would be impossible to feel the difference.
no doubt there is probably a slight decrease in fuel efficiency but again, it would be so minimal i dont even think you would notice
 

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Discussion Starter #6
Of course it is totally subjective but I swear I have to hold on a bit tighter when accelerating. It put a (new) smile on my face.
I didn't mean that it felt like driving a wall down the road, I just meant that without the fairings it must be more wall-like than not.

So in acceleration, I find there is a noticeable difference in pickup. But my concern is once you're done accelerating and trying to maintain constant speed, how big is the efficiency impact.

If anyone is interested, I can post the weights of each part (once I get home). I'm on the fence about re-assembling it again.


Nick
 

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Discussion Starter #7
Each large fairing is just under 2 pounds going from memory- with or without signals I don't remember at the moment.

nick
 

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If the bike was lighter, it could accelerate faster, even if it was less aerodynamic.

The aerodynamics won't affect it much until > 40mph, maybe even more.
 

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By far the biggest weight savings to be had on this bike is by removing the stock muffler, which is close to 18 lbs., and installing a light weight aftermarket exhaust. The FMF Apex Carbon Fiber slip-on that I'm running weighs about 3.5 lbs., so that was an easy reduction of 14 lbs. without having to detract from the overall appearance of the bike.

Although not very practical for normal riding, particularly for riding any sort of distances, another place one could reduce weight is by carrying less fuel in the tank... one gallon of fuel on board instead of a full tank (over three gallons) would drop another 14 lbs. from the curb weight.
 

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Discussion Starter #10
So Motomike. After dropping those 14 pounds, What was your experience? Massive? Moderate? Barely noticable?

Nick
 

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So Motomike. After dropping those 14 pounds, What was your experience? Massive? Moderate? Barely noticable?

Nick
I'm no Motomike, so pardon me for answering. I replaced the stock header and pipe with the LV GP Corsa. Weight loss should have been similar to what Motomike has. I've also upgraded the stock rearsets to woodcraft, and ditched the right side passenger peg. I loss of likely 2-3lbs again. I've also ditched the evap can and associated hardware. A loss of about a pound. The difference? I barely noticed. I only have a few thousand miles on the cbr250, but I have 10s of thousands on my 919, drz, and cr250. Have I ever noticed a big difference in any of the bikes when making a change of < 0.5% in weight? Certainly not. If I regularly ran a track and had a timer I would expect to see a time savings of a fraction of a second at best. As far as sheer getup and go is concerned, again you are only changing the power to weight ratio by a tiny bit. Anything you perceive is most likely placebo effect.
 

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My bike felt a little more agile when I ditched the factory muffler. Ditching the rear grab handles removes another 3-4 pounds I think. I believe that there is a thread here about modifications for weight reduction. Max you'll ditch besides low fuel in the tank is about 20 pounds, and that's with extensive metalworking. No gain in power/acceleration as far as I can tell.
 

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I personally think wind resistance is a bigger factor than weight.
I don't see how increasing wind resistance by removing the aerodynamic parts of a bike could be offset by the weight savings of those parts.
Even a skydiver will hit terminal velocity in a flat stable position no matter his weight and the only way to increase speed from that point is to go into a head down position and make your body surface smaller, less resistant to the wind and more aerodynamic.
 

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I personally think wind resistance is a bigger factor than weight.
I don't see how increasing wind resistance by removing the aerodynamic parts of a bike could be offset by the weight savings of those parts.
Even a skydiver will hit terminal velocity in a flat stable position no matter his weight and the only way to increase speed from that point is to go into a head down position and make your body surface smaller, less resistant to the wind and more aerodynamic.
I agree... removing the side cowls to drop those few pounds that they weigh is not going to amount to much of anything in terms of meaningful performance gains. At the same time, aerodynamics are a big factor for any road going vehicle moving through the air.
 

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Every time I see some guy on Craigstlist, post his obvious sport bike for sale, as a "naked Streetfighter" my brain goes into Interpret function" Translation: "crashed, trashed and smashed, fairings cost too much, so Im selling my ugly salvage title bike" , have you ever LOOKED at these abominations? So why make your bike ugly On Purpose to save a few pounds? Just look at the older Gen 1 Ninja 250, Nice lines, Then look at the Ninja 500 Same bike Except engines and other stuff but basically the same style lines except for the fairings, but the short 2 pc fairing on the 500 makes it ugly in comparison to the 250, Just as most people Should leave their clothes on, leave the CBR's clothes (fairings) on, Most naked bikes (and people) should only be (seen) in the dark.:eek:
 

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Discussion Starter #17
Thanks everybody for your thoughts. This is a very active forum! I said that I'd post the weights of each part I had off, but I only remembered to do that after I had it all re-assembled to the bike (So I couldn't do it).

Nick
 
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