Suzuki GS500 Fuel Economy

[roosterk0031]

Concours don't wear out, they more often die a sudden death from hydrolocking.

I went thru most of the thing on your list, didn't lower floats quite that far or cut the windscreen, not concerned with MPG just trying to make it run right. It's a good bike, but not for the average person. And those COG people are just plain cheap.

[redyaris]

Originally Posted by galahs

The GS500 and GS500F are great alround bikes with decent power and great fuel economy.

The air cooled, twin will easily cover 370km from 17 litres sitting on 110km/h. I have got the best fuel economy at about 80km/h where I can get about 3.5L per 100kms.

When conserving fuel, I find as long as I up shift at 5,000rpm and at lower speeds keep her at about 4,000rpm I get really good economy without labouring the engine.

I increased my front gearing from 16 teeth to a 17 tooth sprocket, and this has resulted in about a 300rpm decrease which has made doing highway speeds more economical.

I am presently working on a pair of aluminium Cargo boxes that will fit close behind the riders legs above which I will mount a long tapered cargo bag right behind the riders back, in the hope that I can get to 87mpg. I have also bought a new rear tire [Dunlop D404, 130/90 - 17] that is 7% larger than the stock tire and will bring the rpm at 110 km/hr [70mph] down to 4100rpm. If this all works as planed then it will be worth going to Carmel California [2500km from here] and the Vetter challange!

[alvaro84]

Do you have any info about those D404s' rolling resistance?
Or about any motorcycle tyres?

[redyaris]

Originally Posted by alvaro84

Do you have any info about those D404s' rolling resistance?
Or about any motorcycle tyres?

No I have no info on RR. What info I do have is that they are what where used on the original 4 cylinder Gold Wings and they have a load rating of 315kg and can be inflated to 280 kpa. One of the problems I am attempting to address is the short life of the original Bridgeston BT45, which is only about 8000 - 10000 km. The bonus is that they are 7% larger and thus they reduce the engine rpm at any given road speed. The problem that may arise is the clearance to the fender. I have done the basic mesurements and it looks ok but you can only be 100% sure by doing an instalation and test ride.
You can get motorcycle tire info on the web at bridgestontire.com or dunloptire.com or do a web search for motorcycle tire. They don't seem to have wear ratings or RR for motorcycle tires on the web that I could find.

[alvaro84]

Originally Posted by redyaris

One of the problems I am attempting to address is the short life of the original Bridgeston BT45, which is only about 8000 - 10000 km.

Huh, that's not too much.
I got Teresa with a pair of used Metzeler Z6s, and those lasted ~21000km. I was satisfied with them so I replaced them to a new pair of Z6s. Those are quite weary too now, I'll get them replaced this spring. It'll be ~27500km for them with pretty much 2-up usage. The workshop has some Heidenau which are optimized for rain, they say - I may give them a try, last year was very rainy. I worry a bit that their RR could be higher, though.

[redyaris]

alvaro84 you need to add your bikes to the ecomodder team FE contest. We 2 wheelers need to show the training wheel set what real FE is.

[alvaro84]

Originally Posted by redyaris

alvaro84 you need to add your bikes to the ecomodder team FE contest. We 2 wheelers need to show the training wheel set what real FE is.

I don't really ride Cliegia (the GV250) much anymore, we bought her to my girlfriend and she got her license last year (and the FE gets better since the training finished ). But I can add Teresa, indeed. I don't know about this FE contest too much, where can I read more? I suppose it has an own topic (or more).

[redyaris]

Originally Posted by alvaro84

I don't really ride Cliegia (the GV250) much anymore, we bought her to my girlfriend and she got her license last year (and the FE gets better since the training finished ). But I can add Teresa, indeed. I don't know about this FE contest too much, where can I read more? I suppose it has an own topic (or more).

the way I get to the page is contrived what I recomend is do the ecomodder search and type in ecomodder team competition and and then click on ecomodder team competition, then select motorcycle, then enter your bike.
this could be entertaining.

[alvaro84]

Originally Posted by redyaris

the way I get to the page is contrived what I recomend is do the ecomodder search and type in ecomodder team competition and and then click on ecomodder team competition, then select motorcycle, then enter your bike.
this could be entertaining.

Joined
Now I have to go, but I'll read the topic later...

edit. oh, and I forgot:

[beatr911]

redyaris, I see you had planned a warm air mod. Suggest you weld in an O2 bung and plug in a universal O2 sensor to an AFR gauge. You are probably wanting to be close to a stochiometric mixture anyway so a wideband sensor/gauge isn't necessary. The resolution of the inexpensive narrow band sensor/gauge will help you manage the temperature of the air to optimize the mixture. I have one on my Zongshen 200 and it easily detects the mixture difference of the three different exhausts I've tried. You may also see benefit from changing the stock jetting or settings as is.

By cutting the stock windscreen down on the Concours about 4 inches, I recorded a consistent increase of about 2mpg. Seems that in my case the large size of the barn door was good for winter protection but increased drag. Did you see an increase of FE with the larger screen?

To maximize the engine to run at lower speeds due to the taller gearing, investigate advancing the cam timing. This will take some studying of your stock cam lift and timing and comparing it to other slow speed engines, say a Harley or other cruiser. Modification may be as simple as redrilling holes in the cam gear(s) in precise locations by a machinist. The Concours picked up a healthy low and mid range boost by advancing only the exhaust cam by 7 degrees. Mileage was unaffected, but it's overpowered to begin with and turns 4000rpm at 70mph so no advantage was expected.

Recent activity on the Concours forum describes a modification to the airbox inlet where the inlet is restricted to almost half of its original design. I don't claim to understand the resonance benefits but those who try it rave. Search for "2 minute mod" on concours.org. Combined with jetting changes, you may also benefit. Also boosts low and mid range.

This thread is an interesting one on an overlooked bike. Looking forward to more and seeing you compete in Lacey and with Vetter.