1990 zx6 at 55mpg
 

I recently purchased a 1990 zx6 with 30,000 miles. I downsized from a 1000cc yamaha. I have put 3,000 miles on this bike since purchase a few months ago and have been averaging 40-45 mpg. This is with commuting, alittle touring, and some spirited riding up the canyons.

I have decided to ride year round and want to get the max fuel mileage I can while commuting to work. I have been considering trading my bike for a ex250, but decided to try and see what I can do with this 600 first.

My commute consists of 11 miles one way. I ride home for lunch so I make this trip to and from work twice daily (44 miles daily). The commute is half city and hi-way but the hi-way does have a couple lights installed which really sucks for mileage. It has been between 15-40 degrees over these last three tanks so no ideal conditions for high mileage but I have been able to get 55 mpg over the last 3 tanks.

I have made no modifications to the bike, jetting, gearing, or aero. I get into a full tuck over 50 and cruise at 62 mph while on the freeway and usually 30-40 in town. Tires are 36 psi front and 40 rear. I will keep this updated but I really think that as the weather warms up and with some gearing changes I can get over 70 mpg out of this bike commuting. If this is possible I may forget the 250.


It is the bike in my avatar.

Quits, Welcome to ecomodders. Good job with the riding adjustments. Gearing up should help a lot and is very easy to do. There is a lot of good information here on aero mods if you really want to push the envelope. Check out Craig Vetter's website at Craig Vetter, designer and inventor of the Windjammer fairing,Triumph Hurricane Motorcycle and fuel economy motorcycles for more great information on motorcycle streamlining.
all the best , L&S

Thanks, I have really enjoyed the site so far.

I plan on gearing 17-45 from my stock 15-45 and see how it does. I'm pretty sure I can keep the stock chain length with that setup. I was really surprised at 55mpg out of a 600cc 100hp motor considering the outside temps are usually around 30, and I have 3 cold starts with choking required everyday. I also have stoplights on my route to work so I will have to stop and go atleast 8 times on each 11 mile trip.

My conditions are far from optimal and I feel as though I am getting pretty good numbers from a stock bike. I don't think 80mpg is impossible with better weather and no stop and go. Add in gearing changes and no cold starts it shouldn't be to hard I presume, but I haven't been able to find any info on these types of bikes and good mpg #'s. Although I doubt anybody buys them for this purpose.

From everything I have read it appears impossible to get much over 50 out of these racing motors, but I like a challenge. Also everyone seems to like the 250cc bikes and I even read of a few hitting 100 mpg with them. I want to be different and my goal is to consistently hit 70 mpg commuting, and 80+ all freeway cruising on a weekend cruise.

I will definately look into custom fairings or possible modifications to mine in the future. I will probably look into skinnier and taller tires as well.

I am also curious as to why the older carbed bikes seem to do better than the newer ligher fuel injected ones?

This seems extremely odd to me.

My bike weighs in at nearly 500 pounds wet. I am 230 without gear so this also makes me feel better about my numbers considering all the factors that don't help with optimal mpg.

I had a 93 zx600e, I assume your's is a D model, traded it for a ex250, big mistake, the ammount of mpg difference isn't worth the quality of the ride. I haven't ridden a D, but if it's close to a E, it was nice, imcredibly smooth to redline, tight, smooth handling, good brakes, prefect for me as far as ergonomics. I down sided from a FZ1 to the zx600e, then to the 250, back up to a concours zg1000.

Should have stoped trading before I started and stuck to the FZ1 or even better the KLr650 that came first.

By the way never got consitantly over 45 mpg with fz1, zx6e or KLR650, the ex250 might of, just hated riding it so much only put 3k on a 2004 before dumping it. I'd rather ride my KDX200 to work than than a 250 ninja. The advantage was KLR650 because of the price of tires and versatility, to be able to work, go exploring gravel on the way home, play in the dirt with the kids, or go deer or squirel hunitng.

That's funny because I downsized from a first gen fz1. I like this bike so much better except for the brakes. I am going to keep this one and see what kind of mileage I can get before considering trading to a 250.

I don't think there were many differences between the d and e models. I believe the e's had ram air.

I have ordered a 17t front sprocket and will have it within a week or so. I should be able to get one maybe two tanks before it gets installed (depending on weather of course). I don't think this fourth tank is going to be as good as I have had really bad wind while commuting and the traffic has been more backed up than usual.

I also adjusted my air/fuel mixture screws as they were turned 4 turns out. I have been adjusting them down in half turn increments. The book says 1.5-2.25 so maybe this will help alittle.

Also aired up my tires to 40 front and 45 rear with no significant change in performance.

I have 40 miles on this tank and will keep this updated.

Isn't more turns out richer? I cleaned the carbs for the zg1000, but took me a acouple tries to get it right. Check out the concours group website lots of tips that mayl apply to the zx6d. Lowering fuel level below the carb bowl/body separation about 1-2 mmm, adjusting without pulling them would be impossible so I wouldnt bother unless pulling them to clean them. If you are needing to plan on buying new boots for both sides of the carbs.

Since your already getting 55mpg, I think you are almost as good as they you can get. You maybe able to get more by accerating under heavier load, but still shift quick and keep rpm's down, possible skipping ever other gear.

Out is richer. Mine were 4 turn out, and the manual states 1.5-2.25 turn outs ( so leaner).

I have noticed that if I try to full choke it will flood, and when the choke was on I couldn't give it any throttle or it would die.

I have now turned the mixture screw in so that they are 2 turns out and it is noticeably better. I am just thinking that this might posibbly help a small amount in my mpg.

On some carbs it is. Depending on where the idle mixture screw is positioned, it may be an air-bleed and not a real adjustment of fuel flow. With an air-bleed adjustment, turning the screw out opens the air passage and leans the mixture.

All of the cycle carbs I have worked with (mostly dirt bikes) have been air bleeds, but that's not always the case.


55 MPG from that cycle is doing really well! My '06 SV650 (F.I.) has a reputation for getting decent mileage, and I'm getting 53-55 MPG on the hwy at 70+. Best I've done with it has been 58 MPG during some light backroad riding.



Jay