Suzuki GS500 Fuel Economy

[redyaris]

Thanks for the O2 sencer Idea I like it. I was also thinking about instaling a vacume guage, but finding a mounting spot on the existing dash is a problem. I have a plan to expand the dash board to accomedate more stuff like the above two, plus indoor/outdoor digital thermometer w/clock and GPS/data logger. As for cam timing I don't have the time for that this year and I suspect the present todo list is overburdend!
I have never been a big fane of changing Jeting on carbs unless you have some way of monitering. In my case I am making so meany other changes that are of greater benifit for FE that playing with the carbs at this stage is ill advised. After I get the O2 and other guages in place I may find evidence to make jetting changes.

[beatr911]

That is a good plan for the O2 sensor. If no changes are made to the engine systems you're mixture is probably pretty good. Jetting changes made with plug checks is a guess at best with todays fuels. Feedback is the only way to do it with any sort of accuracy. The GS500F carbs have 3 distinct circuits and the O2 feedback will let you know how each is operating, something a plug check is very very difficult to do. Because the narrow band sensors and gauges are so inexpensive it's really worth it to use this method for a benefit for years to come.

I question the use of a vacuum gauge, as the CV carbs doesn't let port vacuum drop so far as to be a problem. The good point though is it gives some feedback on engine load, which may be your goal.

[redyaris]

Originally Posted by beatr911

That is a good plan for the O2 sensor. If no changes are made to the engine systems you're mixture is probably pretty good. Jetting changes made with plug checks is a guess at best with todays fuels. Feedback is the only way to do it with any sort of accuracy. The GS500F carbs have 3 distinct circuits and the O2 feedback will let you know how each is operating, something a plug check is very very difficult to do. Because the narrow band sensors and gauges are so inexpensive it's really worth it to use this method for a benefit for years to come.

I question the use of a vacuum gauge, as the CV carbs doesn't let port vacuum drop so far as to be a problem. The good point though is it gives some feedback on engine load, which may be your goal.

Thanks for the feedback on vacuom guage and constant Velocity carb's. I was forced to think more clearly about how they are different from other carb's. the throatle plate opens and closes like other carbs but the vacuom controled slide opens the throate of the carb at a controled rate that is slower than the plate thus the change in manifold pressure is slower/less than what would be encountered with a throatle plate alone. This would result in an atenuation of the vacuom signal. i guess they call them constant velocity carbs for a reason!

With respect to a O2 sensor I would plan to install it in the exhaust cross over tube between the 2 headers close to the heads or further down the exhaust system where the two tubs join before the muffler. What are the pros and cons for that type of O2 sensor? Could you recomend a source, Part number or brand name? Do they come as a kit with a digital read out? My only experiance with O2 sensors is testing them with a scan tool and replacing defective ones, and basic theory of operation. Designing them into a system was not part of my training. This will be a good learning experiance.

[fjasper]

I don't mean to jump in and hijack, I just thought I'd share a couple links that might be helpful, and talk motorcycles a little bit.

The best info I've come across on the web for understanding and tuning constant velocity carbs is at Factory Pro's website:

CV Carb Tuning Procedures

Having an O2 sensor should make the process considerably easier. I bought one of their pre-set kits for my Honda Blackbird, but ended up selling the bike before I put the kit in it.

FWIW, I got about 70mpg US out of my old KZ400, and 53 from the KLR650. A non-oring chain has noticeably less drag than a sealed chain. Non-oring chains need good lube though (or at least lots of it-my brother fills his scott-oiler with used motor oil and slathers it on liberally).

This site ( Watt_man on Xanga ) has some interesting info, including test results on an o-ring chain run for 34,000 miles using only WD40. He also makes a thermostat modification for the KLR that allows much better control of engine temperature. The same principle should apply to other water-cooled bikes. My air/oil cooled bmw has a thermostatically regulated oil cooler, and it maintains the same oil temp from -5c to +40c (20-104 f) as long as you keep moving, but the thermostat itself is ridiculously expensive (~$200, IIRC), so it might not be a worthwhile mod. Other makes might have the same kind of thing for a more reasonable price, though. (BMW stands for Bring More Wampum and I don't mean the seashells.)

The type of road surface seems to make a big difference to tire life. Where I usually ride, they use sharp crushed gravel in a seal-coat on top of asphalt. Very good traction, but short tire life (~6,000 miles from BT020s on an R1100RT). I've heard of people getting 50% more miles out of the same tires on the same bike in parts of the country where they use concrete for the driving surface. Some people in the SW US report getting even fewer miles than I do out of a set, probably due to high temperatures on a similarly abrasive surface.

[redyaris]

beatr911
I have looked into the O2 sensor thing; on the web, and have found wide band kits [they call them fuel/air ratio guages] that range in price from $190 to $350, plus shipping. some have provisions for data logging and narrow O2 sensors for indevidual cylinder monitoring etc.
What is the advantage of a narrow band sensor over a wide band sensor?
What does a narrow band kit cost?

fjasper
I looked at the link for cv carbs, however I have never had a need to adjust any cv carb I have owned. I have adjusted the carb on a XR100 that I used to mini road race. In that case it was because of modifications to the engine that provided more air flow through the engine which resulted in White spark plug electrode, Indicating leaness! i changed the main jet two sizes bigger and the plug came back to a nice light tan colour and we did quit well in the 3hr endurance race without any damage to the motor.

[kawboyCAFE]

Originally Posted by fjasper

This site ( Watt_man on Xanga ) has some interesting info, including test results on an o-ring chain run for 34,000 miles using only WD40.

well, i would say the so-called report documenting this is bullcrap. WD-40 is one of the worst things you can use on an o-ring chain. it actually dries out the seals quicker, causing the chain to fail prematurely. this has been tested and proved time and time again.

[fjasper]

I've had sort of similar results. Seems like once a carb is set up for the induction and exhaust system, it's a matter of keeping it clean and checking sync once in a while. The CV carb is a supremely elegant machine.

My wife's Toyota had a CV (variable venturi) carb in it, but it had a lot of trouble. The slide was mounted horizontally, ran on dozens and dozens (literally) of tiny little bearings, and it never worked right after a certain shop gave it a "tune-up." It also wasn't designed to be serviced, only replaced.

I still haven't forgiven Toyota for that little bit of cheapskatery.


Redyaris:

I believe a standard (narrowband) O2 sensor can be had for $50-75 in generic form. From what I understand, a wideband sensor will detect and accurately report a much wider range of fuel/air ratios, which is particularly valuable for the early stages of tuning. The narrow band sensors are made to work as part of a system that's been engineered in detail, so they don't need to be able to detect big deviations. When it senses a condition outside the known parameters, it pitches a CEL/MIL and you dutifully take it to the dealer to get it fixed. Right?

Output from an oxygen sensor on a carburetted engine will probably look different than from the same sensor on a fuel-injected engine. I don't think the carb'd motor would produce the voltage swings characteristic of a FI system in closed-loop mode, but I could be wrong.

It'll be interesting to see if the cross-pipe has enough flow/heat to make the sensor work. Individual bungs on each pipe might work better.

I stand by, ready to learn from your experience!

[fjasper]

@KawboyCAFE

No disrespect, but it is kind of comical to see how much emotion swirls around WD40 (and lubricants in general-see bobistheoilguy.com/forums).

YMMV, if you don't like it, don't use it, etc. I've run several other (coincidentally(?) MUCH more expensive) chain lubes on several o-ring and x-ring chains and didn't like the results. So I switched to the cheap stuff.

I don't understand why my chains got noisy and stiff with the high-dollar stuff, but they did, and the cheap "can't-possibly-work" lube made it work better. 90w on the fast bikes, WD on the slow ones.

One of the other forums I sometimes read, has a "beating a dead horse" emoticon. If I could put one here, I would...

[beatr911]

Universal 1 wire O2 sensors I think are about $35. An inexpensive gauge is about the same, maybe less if you shop around a bit. A bung on the exhaust is about $5 if you weld it on yourself and maybe $15 if you mark it, take off the pipe and take it to a muffler shop for the work. The sensor needs to be about 600*F to begin working and should have good gas flow in the pipe. Suggest not putting it in the crossover but in one of the downpipes in a convenient location. On the street, both cylinders will run very close to the same so there isn't really much need to monitor both.

Used with the on the non-feedback carburetor on motorcycles, the gauge will not oscillate between rich and lean like a car would. It will just stay at whatever the mixture is for the throttle setting and load. Some reading to understand how to tune CV carbs will give you a really good idea on what circuit you are reading on the gauge at any point in time while riding. No plug checks, no changing jets to see if "one more" will make it too rich or lean. The other benefit is you can see what effect temperature and elevation really have on your jetting. Guessing pretty much goes away. It's also removeable, you can disconnect and insert a plug into the bung with no ill effects. Consider a semi-permanent installation to dial in, then store it in the garage when complete.

Maximum power is achieved at 10-12 to 1 while maximum efficiency is just over 15 to 1 air to fuel while stochiometric is 14.7 to 1. So you can see that the tuners usually want to go rich and be accurate there. Us FE guys want to be very near stoch, but just a tad lean. Much leaner than about 15 to 1 and the burn slows to the point where it's still burning when the exhaust valve opens. All that wasted burn (potential work) goes out the pipe and not pushing down on the piston. The mildly rich 13.5:1, to stoch, to mildly lean 15:1 area is where the narrow band shines, it is designed for accuracy in these zones. The wideband setups are really good for dialing in rich maximum power mixtures and can be good at lean mixtures, but are overkill for our needs.

Right on fjasper! For a street bike the lowest friction is indeed a quality non-oring chain and a Scottoiler. Changing to this set-up when the stock chain wears out can net a reduction in operating cost as the increased chain life by the automatic oiler pays for itsself with extended chain/sprocket life. I don't know how much it will affect MPG though, no measurement by me.

Also I really like the idea of using filtered waste engine oil with the Scottoiler. I'm always looking for responsible uses for it. Heck, I even add it at about 150:1 to the fuel. Of course it's filtered to about 1 micron first with a homemade gravity feed toilet paper filter.

[redyaris]

From what I have seen on the web, from what I already know, from the information you and fjasper have provided I am inclined to go with one of the wide band kits at less than $200 plus shipping. Although they are more expensive than the recomendations you make beatr911 I like the Idea of a complete kit that all works together. I will reasurch some more and make up my mind in a few days.

What to do with used oil? I use it on the lath, milling machine and drill press when machining.WD40 works as well. anything I don't use I bring to the recycling depot. I use synthetic 5W30 in the Yaris and after the first 8000km oil/filter change I went to 20000km oil/filter change intervals and now its once a year at around 22,000km. I have just over 100,000km on the car. so I don't get much used oil. Like fjasper I am often surprised by the pashion of some people when it comes to opinions on lubricants.