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janvos39 02-01-2009 07:47 AM

Suzuki Burgman modification (aerodynamics + gearing mods)
 
http://cyberfox.sohosted.com/burgman/img1.jpg
http://cyberfox.sohosted.com/burgman/img2.jpg
http://cyberfox.sohosted.com/burgman/img3.jpg
http://cyberfox.sohosted.com/burgman/img4.jpg

Last year I started modifications on my Suzuki Burgman 385 cc to look for a better fuel efficiency.
Inspired by the work of Graig Vetter I bought this Burgman early August 2008.
Riding it for some weeks unmodified to measure fuel usage. This appered to be 4.3 to 4.4 L/100KM. (54 MPG) Not bad for a scooter of this power to start with. I have a fixed route in driving to work. Mixed highway (75 MPH), road with 50 MPH limit and city driving with stop-go situations.
On my wishlist for modifing was also comfort. I like to sit upright so that I can ride without saddle or backpain over longer distances.
With the modifications as shown on the pictures this is already filled in. You hardly feel any wind which translate in more comfort certainly at colder days.
This is a big difference with unstreamlined bikes. Also some light rain is hardly noticed driving with streamlining like this.
The MPG improvement is not that big. I typical measure at filling the tank at the gas station that I have a 4L/100 KM (59 MPG) average.
I expected better, but realised that although I need less throttle the rev's stay the same and the specific fuel consumption per HP is worse with lower load.
The plan is for improvement of this to add an extra gear which will act as an overdrive. Gears are already cut but still to be implemented. And the gear shift mechanism must stil be made. Available time is at this moment the limiting factor. But this story will be continued when gearing is changed.

Two questions where somebody might have the answer.
Is there a MPG reader available in the market for a Suzuki Burgman of 1999?
Does somebody know where a BSFC map for Suzuki can be found?

Jan

The Atomic Ass 02-03-2009 05:49 PM

Since that's a carb'd bike, I don't think you'll be able to get an MPG display for it. As for gears, you can look into one of the aftermarket CVT options, I forget which one, but one of them reduces RPM's at highway speeds by 500 or so. You'd gain a LOT by slowing down from 75 to 65. Even more going down to 55.

I'm assuming you've already done the routine maintenance stuff on it, oil change, air/CVT filter cleaning, belt change, valve adjustment? The belt change is the big one. My Burgman is only getting down in the 50's in the winter temps, during the summer I was into the 70's (with poor aero, as mine was wrecked and never fixed). And I still need to do a valve adjustment and replace the belt and CVT. (CVT pulleys seem to get worn down from the belt itself, the aftermarket units don't exhibit this problem I am told).

Very interesting work you've done thus far, are you planning on dog-housing the front wheel? I imagine that would make for a big increase in efficiency.

MetroMPG 02-03-2009 09:26 PM

Welcome to the forum, Jan.

Interesting to see your mods. I've been following Vetter's latest project, and he also didn't achieve the large improvement he was expecting.

If I'm not mistaken, he blames it partly on the CVT on his bike: apparently the old Honda he's working with can't be geared any taller.

Please keep us informed!

Frank Lee 02-03-2009 10:27 PM

I'm tempted to put mail in the back of it.

Cool project! :thumbup:

blueflame 02-04-2009 04:12 AM

While at the scooter shop 2 days ago a guy was buying a high speed pulley for his Burgman, maybe with a slightly wider performance belt the ratios would upgear considerably.... Gear up kits for the final drive should be available too? Quite simple on a CVT scooter, just 2 small shafts in the rear axle.

Larger diameter rear tyre too...

A lot of drag in that scooped body area behind the front wheel...

janvos39 02-04-2009 12:30 PM

I am thinking of a way to improve on the dog house or also called scooped body. That will come after implementing other gears. The new gearing will be first.
The standaard 14 at 31 step 1 and 14 at 39 step 2 gears will be replaced by 14 at 29 (step 1) and 13 at 37 teeth.(step 2) All spur gears, home made.
Additional I will be able to shift to a second ratio for step 1 with 16 at 27 teeth .
I will add later some pictures of the gear sets. So gearing drops approx 20 %.

The Atomic Ass 02-04-2009 01:16 PM

Quote:

Originally Posted by blueflame (Post 86399)
Larger diameter rear tyre too...

Impossible. The current rear tire has less than 1" of clearance from the rear of the engine block as is.

The Atomic Ass 02-04-2009 01:19 PM

Quote:

Originally Posted by janvos39 (Post 86427)
I am thinking of a way to improve on the dog house or also called scooped body. That will come after implementing other gears. The new gearing will be first.
The standaard 14 at 31 step 1 and 14 at 39 step 2 gears will be replaced by 14 at 29 (step 1) and 13 at 37 teeth.(step 2) All spur gears, home made.
Additional I will be able to shift to a second ratio for step 1 with 16 at 27 teeth .
I will add later some pictures of the gear sets. So gearing drops approx 20 %.

I think you might find that large a drop to basically kill the clutch usability. On mine the clutch will not fully engage until 15mph, with those gears it'll be around 20mph. That will make for very unfriendly clutch activation in the city.

But when you say you'll be able to shift to a second ratio... Do you mean you're making it shiftable while riding, or that you'll be able to swap to even higher ratio gear if you feel it's needed in the future?

janvos39 02-04-2009 02:06 PM

Indeed I'll make it shiftable with a dual cable connection so it can be shifted by hand. Like an old type of gearshift on a steeringwheel.

janvos39 02-04-2009 02:09 PM

You are right of course on the speed of 20 Mph for full clutch engagement. Therefor I intend to shift to the second gear at approx 40 Mph outside the city.

The Atomic Ass 02-04-2009 09:05 PM

Quote:

Originally Posted by janvos39 (Post 86443)
You are right of course on the speed of 20 Mph for full clutch engagement. Therefor I intend to shift to the second gear at approx 40 Mph outside the city.

Are you intending to go with a taller gear for the 1st gear? As in:

Old stock ratio < New 1st gear ratio < New 2nd gear ratio

OR

Old stock ratio = New 1st gear ratio < New 2nd gear ratio

I'm not sure if I read correctly, but it sounds like the former. The latter would actually allow you to get off the line better around town.

I think you might find the former uses MORE fuel in town due to having to rev the partially engaged clutch against the higher gear ratio, and also causes more clutch wear, along with very poor takeoff.

I think having a shiftable ratio for lower RPM's on the highway is a very good idea, if a massive undertaking. Please provide pics if/when you get around to working on it. :thumbup:

janvos39 02-05-2009 02:24 PM

Atomic,

My first new gear is actually 5% above std gearing. I expect that with riding solo on the bike (no place for a passenger) and mainly on flat roads this will not present a problem.
Std reduction of gearbox is 6.168. My new first is 5.896. The new second is 4.803.
But probably you calculated that already based on the number of teeth for the various gear wheels mentioned in a earlier post.
regards

janvos39 02-06-2009 04:48 PM

http://cyberfox.sohosted.com/burgman/img5.jpg

http://cyberfox.sohosted.com/burgman/img6.jpg

Here the pictures of the gearbox with additional gear
The changing gear mechanism is on the drawingboard. (No hardware is made yet.)

MetroMPG 02-06-2009 04:58 PM

This is getting more and more impressive.

CobraBall 02-06-2009 07:13 PM

How does it handle in crosswinds?

The Atomic Ass 02-07-2009 10:29 AM

Quote:

Originally Posted by janvos39 (Post 86571)
Atomic,

My first new gear is actually 5% above std gearing. I expect that with riding solo on the bike (no place for a passenger) and mainly on flat roads this will not present a problem.
Std reduction of gearbox is 6.168. My new first is 5.896. The new second is 4.803.
But probably you calculated that already based on the number of teeth for the various gear wheels mentioned in a earlier post.
regards

Truly flat roads would certainly make it easier. It's hard to find those in my area. :(

Nice work on the gears, is the gear-changing mechanism going to be on the input or output side?

janvos39 02-07-2009 01:21 PM

Handling in crosswinds is comparable with an unmodified bike. Although when there is a constant crosswind the lean angle of the bike is larger probably due to the larger side surface. You get used to that.
The gear change mechanism will be on the output side. I had to shift the diskbrake some mm to make space for the shift mechanism. Still I have limited space for the shifter.

janvos39 04-26-2009 09:17 AM

It is about time to report some progress on the Suzuki Burgman project.
The project basically is twofold. Improving the aerodynamics of the Burgman and improve the engine characteristics to support good mileage.



http://cyberfox.sohosted.com/burgman/img10.jpg
The progress on making an additional gear is not fast, but I made some parts for the shifter. On this photo the center bar is shown that engages the two gear ratios. The banana shaped hollow part brings the movement to the outside of the gearbox. A push pull rod has to go in the aluminum housing. A cable connection then will be made to manually change the gear.
I found out in the mean time that the newest Suzuki Burgman 400 has a changed gear ratio. This is about 5% higher than older models of the 400.
So my choice for the lowest gear is now identical to this.

http://cyberfox.sohosted.com/burgman/img7.jpg
To improve comfort on the early morning rides to work I added covers over the handlebars. To be able to do this I had to mount the screen and the covers to the steering. By doing this I decided to give the screen a smaller angle for possible improvement of the Cd.

http://cyberfox.sohosted.com/burgman/img8.jpg

http://cyberfox.sohosted.com/burgman/img9.jpg

http://cyberfox.sohosted.com/burgman/img11.jpg
The last picture shows the large potential storage capacity.

MetroMPG 04-26-2009 09:41 AM

Thanks for the update, Janvos. Any new fuel economy reports?

janvos39 04-26-2009 11:03 AM

http://cyberfox.sohosted.com/burgman/graph.jpg

The graphical representation of the fuel used for the Burgman is put together from the quantities of each tank fill.
Since I dont have a fuel gauge this is the only way to work. I am looking at the average, which is of course also influenced by driving style , traffic conditions and weather.

The Atomic Ass 04-26-2009 11:59 AM

Quote:

Originally Posted by janvos39 (Post 100495)
I found out in the mean time that the newest Suzuki Burgman 400 has a changed gear ratio. This is about 5% higher than older models of the 400.

http://cyberfox.sohosted.com/burgman/img9.jpg

I hadn't heard that. I assume by newest you're referring to the 2007 and later models?

Also, it looks cozy. :D I need to find some coroplast and then rip-off your design. :p

janvos39 04-26-2009 02:48 PM

I found out about the different ratio when I bought a 400 injection engine from a totall loss Burgman.
The way it is now it is indeed cosy and very comfortable , certainly when I start driving at near freezing temperature. I can recommand it.

janvos39 04-26-2009 05:12 PM

Found nice example of Dutch project with 125 cc bike

Allert

Electric Frenzy 04-26-2009 05:32 PM

it would be a lot more work but my honda reflex 250 has a 2speed CVT that works like what you're talking about. It's a full cvt but there is a 2step final drive built in that allows you a shorter gear for 0-40mph and a taller gear for 40-80mph. Its a little clunky during the transition phase but there is a fix for it to keep it nice and smooth.

if you could find an old Reflex transmission all you'd need to do is mat it up to the current 400cc engine and it seems like that may be easier than trying to fabricate your own from scratch.

The Atomic Ass 04-27-2009 12:03 AM

Quote:

Originally Posted by Electric Frenzy (Post 100551)
if you could find an old Reflex transmission all you'd need to do is mat it up to the current 400cc engine and it seems like that may be easier than trying to fabricate your own from scratch.

Not that easy, the Burgman engine and transmission are in the same case.

The Atomic Ass 04-27-2009 12:05 AM

Quote:

Originally Posted by janvos39 (Post 100534)
I found out about the different ratio when I bought a 400 injection engine from a totall loss Burgman.
The way it is now it is indeed cosy and very comfortable , certainly when I start driving at near freezing temperature. I can recommand it.

Is that injected motor working? I'd think you'd be able to swap that in and have a quick boost in FE right there.

And I've ridden down to -7F. Ya' need electric heat at that point. :D

janvos39 04-27-2009 02:19 AM

No it is not yet working. I aim still looking for ECU which was not available. Probably I have to start with a carburettor to get it running. I need an engine to replace existing one when I start rebuilding the gearbox to the additional drive.

janvos39 04-27-2009 02:24 AM

Hi Electric frency you can see nothing news in engines. The reflex solution is by my knowing not used in my area. Do you have some drawings or pictures to show? I am very interested in their solution.

SVOboy 05-05-2009 06:49 PM

Wow, I can't believe I never opened this thread, great stuff :thumbup:

cvetter 05-05-2009 08:50 PM

Vetter on the Burgman
 
Hooray! I am so happy to find this site and to see that there are others interested in fuel economy. I must leave right now but I want to invite all with street streamliners to my first "Gathering of Streamliners" to be held in conjunction with AMA's Vintage Days in Ohio at the end of July in 2009.

Thank you, I will be back.

Craig Vetter

SVOboy 05-05-2009 09:06 PM

Quote:

Originally Posted by cvetter (Post 102456)
Hooray! I am so happy to find this site and to see that there are others interested in fuel economy. I must leave right now but I want to invite all with street streamliners to my first "Gathering of Streamliners" to be held in conjunction with AMA's Vintage Days in Ohio at the end of July in 2009.

Thank you, I will be back.

Craig Vetter

Yay! The master himself is here! We all love your work, hope you stick around!

MetroMPG 05-05-2009 09:40 PM

Craig - I'll second Ben's enthusiastic welcome to the forum!

As you've seen around here, you've sure inspired a lot of people to learn more about aerodynamics.

If I were near Ohio at the end of July instead of on Canada's east coast, I'd definitely be checking out your Streamliners meet.

cvetter 05-05-2009 11:57 PM

Quote:

Originally Posted by MetroMPG (Post 86370)
Welcome to the forum, Jan.

Interesting to see your mods. I've been following Vetter's latest project, and he also didn't achieve the large improvement he was expecting.

If I'm not mistaken, he blames it partly on the CVT on his bike: apparently the old Honda he's working with can't be geared any taller.

Please keep us informed!

Vetter here: I am not truly streamlined yet. I am not close to my goal of 100 mpg at 70 mph, into a 20 mph headwind. I am at 64 mpg in worse conditions. What I am learning is that covering over the right side, at least, has made a dramatic improvement. If the Helix could be geared higher, I have the feeling that it could top out at 90 mph or so. No head wind has been able to keep me from going 75 mph! And that is as fast as a Helix might go in no winds! I am not discouraged but the Helix is not up to 75 mph. Gotta start over and am soliciting suggestions.

Otto 05-06-2009 02:33 AM

Craig, why not start with the human-powered designs as seen at the Battle Mountain HPV competition. Last I checked, they were up to ~81 mph on human power, which reportedly can muster only about ~1/2 hp. Obviously, to get such results necessitates very good aero design. That said, seems to me even those streamliners are not the final word on efficiency.

Geebee 05-06-2009 04:03 AM

I second looking toward the hpv streamliners, fit bomb bay doors for stopping etc.
This is the Varna Diablo, they dont come much faster on limited power.
http://www.recumbents.com/wisil/whps...es/diablo1.jpg

janvos39 05-06-2009 06:36 AM

Every body who works on modifying a two wheeler for more speed or FE has some things to consider. For me it is important to have a daily transport to work which allows me to travel under not optimal weather conditions. furthermore I like to sit comfortable upright so that no back pain or things like that occur during the ride.
Although I admit for best FE the solution for the shape will be close to the HPV streamliner. This does not fit in my specification for comfort.
So far I reached more or less the goal of comfort. The choosen shape also starts to work for the FE.
Still to be done for better Cd is the front wheel streamlining.
I am not sure if I best cover the whole wheel or do additions to the front fender to improve the streamlining.
For the longer run I want to use a modified Suzuki Burgman frame that gives me a lower seat position and a smaller rearend for better closing of the back side.

On the gearing part there is the question what is best rpm at the cruising (75 MPH in Eu) speed. With the standard Suzuki Burgman 400 this is 6550 rpm (for the Suzuki Burgman 250 this is even close to 8500 rpm)

With the new gearing for the Suzuki 400 this will be reduced to 5100 rpm at 75 MPH in the additional overdive gear . See what that will bring on the FE.

Geebee 05-06-2009 06:49 AM

I dont understand how a more upright seat is more comfortable than say a 40 to 30 degree's from horizontal fully supporting seat is? such as:
http://farm4.static.flickr.com/3358/...87596b.jpg?v=0

Cheap fairing that allows 85 kph where a normal bike does 25 kph, above 30kph aerdynamics are everything.
http://farm4.static.flickr.com/3624/...b1a7d4.jpg?v=0

Otto 05-06-2009 12:28 PM

Quote:

Originally Posted by Geebee (Post 102524)
I second looking toward the hpv streamliners, fit bomb bay doors for stopping etc.
This is the Varna Diablo, they dont come much faster on limited power.
http://www.recumbents.com/wisil/whps...es/diablo1.jpg

Surely, we can make a better way to keep the machine upright at a stoplight than bomb bay doors to put your feet on the ground. Actually, the Swiss Ecomobile of ~20 years ago did this, with automatically deployed trainer wheels. Perhaps something even simpler can be devised, such as cable-actuated trainer wheels where you keep your feet inside the fairing and push on pedals to deploy the trainer wheels, rather than putting your feet down through the bomb bay like Fred Flintstone. Whatever.

Think of a typical bike kickstand, but with a wheel at its tip, extended by cable. Put one on each side of the vehicle so it cannot tip to either side. This also helps to elevate the vehicle to change tires, which is always the problem at roadside when a motorcycle tire goes flat, if said motorcycle lacks a center stand.

As to comfortable position, the semi-supine position has long been shown in sailplanes (and fighter planes such as the F-16) to be much more sustainable and comfortable, as sailplanes have to circle in extended high-G turns while thermalling. This also makes for less frontal area, meaning a lower drag profile for the vehicle. It also puts your head and eyeballs in optimum position to look around.

So, mehinks take the drive system guts of a Burgman, and install them in an HPV stressed-skin shell. On reflection, and given the vastly greater aero efficiency of a Varna Diablo or similar enclosed design, you'd need only a fraction of the power of a Burgman, and therefore a fraction of the Burgman's propulsive and fuel weight.

Such a vehicle could probably be built at less than ~50-60 lbs. It would be much safer than a normal bike, as those HPVs have been dropped at max speed, slid quite a distance, but left the driver unscathed. The Swiss Ecomobile, btw, reportedly suffered a blowout at ~150 mph, slid on its side, yet the driver was untouched. This without benefit of an airbag.

Surely somebody has tried one of those tiny direct-drive-on-tire aux bicycle engines on a Varna Diablo type HPV machine?

Geebee 05-06-2009 08:58 PM

This chart will give an idea of just how efficient the shells can be, Worlds fastest human powered trans Canada record
The best of them can exceed 60 kph on 150watts!

This calculator compares wattage to speed for different bikes and fairings one of the faired bikes should exceed 100 mph at 2000w!
Bicycle Speed And Power Calculator
So even allowing for practicality the machines in this thread have a long way to go.

janvos39 05-07-2009 02:39 AM

Thanks Geebee and Otto for info. It looks like if I use as much as I can from the shells of a HPV Cd will drop. It is more a question of how much can I change and still feel comfortable in full traffic, riding between cars in two lanes, which I find one of the big advantages of two wheel riding. Even with traffic jams I loose only some minutes. The back rest riding position is about 20 degree from vertical. This gives me a good feel in the high speed curves.
Maybe in a new design I can try a little more to gain some cross sectional area.


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