Improving Aerodynamics on a Ninja 500R

[GasSavers_Mr_C]

Thanks for the advice on the tank bag. I have not purchased one yet mostly because I haven't researched what is best (this is the first sport bike I have had, previously I have just strapped stuff to a rack). I would be interested in a used one if you want to PM me.

As far as the cost of the fairing, it is $575 + shipping. That is unpainted, and I still need to get headlight, turnsignals and mirrors on it, but I like doing that kind of work. I paid $1600 for the bike, so I should be able to keep the fairing cost well under that. Plus, my fairing is already pretty damaged (the entire side of the upper fairing is gone on the side I don't take pics of) so I will be paying some money to fix that anyway... thats why I am tempted to go this route.

-Mr_C

[cat0020]

I would not be surprised if shipping for the fairing is in the triple digit.

You might need to rethink the cooling system once that fairing is on, radiator airflow will be significantly reduced. Those exhaust headers will need some airflow to them as well.. they might get pretty hot between your legs without proper airflow.

Magnetic tankbags tend to slide around on the tank, not secure enough to lean against, PM me if you are interested in the tankbag.

[GasSavers_Mr_C]

yah, shipping won't be cheap, expecially since they are on the west coast and I am in the midwest.

Cooling will definately be an issue, although I think that with the opening for the front tire there will be a considerable amount of air coming through, but it might need to be directed to the right area. I need to get a hold of the manufacturer to see what the bottom side of it looks like, and to talk to them about other people who have tried something similar. Unfortunately they don't like email and I have a tricky time calling durring business hours. My bike does have an electric fan on it, which I have never heard come on yet, although living in MN and it never gets all that hot here.

[GasSavers_SD26]

Aerodynamically, you'd really want to keep you feet in the rider position. There are cut outs developed in the tank and in the chassis for that purpose. With your knees in that position, the air flow is going to be like a tear drop. As you move your feet to the passenger peg position, one's knees now represent a separation of the air flow.

The dustbin fairings of the era were made generally out of aluminum.

Cooling will be an issue.

A fairing more like the XR750 would be more available and easier to mount while still allowing for air flow through your radiator. Just cut back the fairing to allow for your knees to fit into the cutouts.


Here's a neat example from Erik Buell, a former H-D employee, when he was developing his bike, a 750cc two stroke race bike. Used a lot of cues from the XR750 aerodynamics, but also incorporated a very specific cut out area also to put the tail and the front fairing together.

[Tepco]

Mr_C, i have the same bike mine is a 1995 the same color. I dont have the lower fairing on. My gas log shows 48mpg but i was having major carb problems. My bike only has 1100 miles and i just got the carbs worked out, so my next entry should show an improvement.

Now for aero i also tuck and use the rear pegs. I cant tuck as much due to a back injury.

I havent checked yet but for many other sport bikes they make a euro windshield that has a lip that directs the air higher making it hit you further up on your body and making it easer to tuck behind.

[GasSavers_Mr_C]

I have run 2 tanks of gas through my bike without the lower fairing and have not seen any measurable improvement. I think I am going to put it back on to complete the A-B-A testing to confirm my thoughs. I would like to do another tank or two, but being that it is now the end of august, my warm weather is going to be comming to an end soon, so I want to get a few tanks in with the fairing on to test the mileage before it tanks due to cold weather.

I am a little dissapointed because I have had a hard time beating the 62-63mpg range on the bike, and I thought that the fresh synthetic oil and removing the fairing, along with careful driving and consistant tucking would get me over 65... but I guess that didn't cut it. Time to look closer at changing the gearing and getting better fairings on the bike.


Tepco, could you post when you get your next fillup? I am currious to see what you can get.

-Mr_C

[itjstagame]

If you've got more than enough accleration and the top speed is way more than you'd ever need, then definately look into increasing the size of your rear sprocket a bit and maybe decreasing the front one too so you can use a similar sized chain.

You can try bar ends too, on my 600R (looks exactly the same as yours but 20 years older) they were just a large phillips. They probably only stuck out 1/2"-1" or so but removing them makes the steering lighter and the bike feel more nimble.

I haven't tried it since my 600R is down for the count, but I had thought of raising tire pressure a bit. You could also maybe trip the foam of the seat down 1-2" which might help you tuck a bit better.

As for the after market front screen that directs air up more, I would be curious if that helps or just increases drag. You could also look into making that 'hump' on the rear seat, not sure where those come from in the aero bike pics, but remember that rejoining your air smoothly is just as important as seperating it smoothly.

As for lower fairing I never noticed any improvements to removing it except it did help keep my bike and headers cooler. In stop and go having that lower fairing on force the electric fan to be used and the headers still got too hot in that enclosed space.

I think the big things you should tri is a larger front wheel fender, remove the lower fairing and move the radiator down a foot or so (but not too close to the header obviously) and then fabricate or buy something to close around where the radiator used to be and the big part of the exposed engine below the tank. I'm not sure what to use though. There was one aftermarket fairing (which was pricey as I recall) that was on solid piece side to side and I think covered the area I was talking about really well. I think it's called AirVortex or something similar.

[cat0020]

Originally Posted by itjstagame

If you've got more than enough accleration and the top speed is way more than you'd ever need, then definately look into increasing the size of your rear sprocket a bit and maybe decreasing the front one too so you can use a similar sized chain.

Large rear sprocket and smaller front sprocket will raise the engine rpm at high speed.... that would require more fuel. Should be the opposite, smaller rear sprocket and larger front sprocket..

Keep the sprocket tooth and number of chain links as prime number.. i.e. 13 or 17 tooth front sprocket, 29, 31 or 37 tooth rear sprocket, and 113 link chain.. I heard that would increase your chain/sprocket lifespan, who knows?

[Philip1]

I have a video from Steve Vetter (yes that Vetter) and this video highlights his fuel milage challenge. bikes had to meet dot rules and be capable of 65mph but other than that it was an open rulebook. This challenge resulted in an 80cc honda capable of 100mph reaching an unbelievable 447mpg. it might be worth a look.

[cat0020]

I would imagine that removing your mirrors on that Ninja would probably have more effect on fuel efficiency than removing the lower bellypan... that and inflate your tires up to 38 psi. see how she rides...