Still having a fuel economy problem.

Most neglected thing on these bikes. Sometimes it takes work and money or something else. Routine maintenance first before going to the carbs. I can't tell you how many times guys will ask about the carbs only to find out the valves were out of adjustment. If I read they haven't been checked, I'll suggest it every time.
BTW, when I was wrenching, I'd put down "check valve adjustments" on the work order. If the customer balked, I'd send them on their way. :whistle:
Steve

Nessism wrote: Is the bike stock? If there were any changes to the air box, exhaust, carb jetting, gearing, etc, then that could explain the poor mpg (which as Ed says, isn't really all that bad).

Other things could be related to the general state of tune. Is the air cleaner fresh? How long since the last valve adjustment? How old are the spark plugs and have you ever check the coils and spark plug leads to be sure you are getting a good spark?

the only thing that isn't stock is the addition of a windshield, saddlebags, and a sissy bar. Everything else is stock. The air filter element itself could probably use replacing.

Spark plugs, coils, and stator were replaced with brand new ones in October, just to be on the safe side.

I know 36 isn't that bad but I'm still trying to bring it up to stock... If you've seen another threat I started recently, after having actually taken the time to prop the front end up on a triple tree stand to replace the bearings, the bearings were totally shot to hell and the front wheel had a ton of resistance to it. I'm thinking that may have in fact been reducing the fuel economy.

I'm pretty sure the bags, sissy bar, and windshield aren't affecting it that much because the same windshield, when it was on a Rebel (which was quite comical to see such a huge windshield on such a small bike) improved the fuel economy considerably over not having one. The sissy bar is rather small and is well within where the windshield and torso have deflected wind around, and the saddle bags aren't all that large. I'm sure the bags and bar may be producing some extra drag, vs not having them, but not enough to account for 10mpg.

Steve, your running gag aside, how often do valve adjustments need to be made? The engine has around 14500 miles on it, and I don't know when the last time it was checked was...

Regarding Ethanol, there are gas stations "in the area" which have ethanol free (in 87 octane only), but I haven't been using them because I have to go out of my way to get to them.

Checking the valves doesn't necessarily mean you'll have to adjust them.
Doing the check is fairly straight forward. adjusting them is more involved but should be doable.

mpgs. How many teeth are on your rear sprocket? It would also be handy to know what size the Fr sprocket is.
A sprocket change can have a fairly significant impact on the fuel economy.

I check my valves at every rear tire change. I burn one up every 5000 miles. They say 3-4000 miles but typically when I do check them I only have to adjust 1 or 2 sometimes none. Wheel bearings will make a big difference in handling and MPG.
Steve

Setton,
As I mentioned in your bearing thread, the factory service manual contains a wealth of information like what maintenance is necessary, how often to do it, and how to do it. There are aftermarket manuals by companies like Clymer, but the genuine Kawasaki factory manual is really the one to have. They are available on fleebay from time to time. There may also be PDF versions running around the Internet that you can download for free. Even if you have to pay for one, it will save you many times the price in mistakes and oversights. Either way, be sure to get one that covers your specific year and model.

Manual. 1980-84 KZ750-4. 1983-85 ZX750. 750turbo.com --- Index .
The pdf manual link is near the bottom of the list -->> GPz750 Base Manual.pdf. good scans. yellow/gold cover.
(there are two complete manuals linked, so be sure to download the good one. the other full manual pdf is poorly copied. the cover is black & white).

Failing the adjust the valves kills a LOT of these old bikes. After 14k miles the valves could very well be burned and damaged already if everyone in the chain of custody for that bike though valve adjustments were optional.

Oh, and if the fairing is large it will increase drag and reduce mpg.

martin_csr wrote: Manual. 1980-84 KZ750-4. 1983-85 ZX750. 750turbo.com --- Index .
The pdf manual link is near the bottom of the list -->> GPz750 Base Manual.pdf. good scans. yellow/gold cover.
(there are two complete manuals linked, so be sure to download the good one. the other full manual pdf is poorly copied. the cover is black & white).

Thanks a bunch! I'd found the other one that's poorly copied on another web page. This one is much better though!

If you have drag on a wheel it will reduce gas mileage along with the windshield and bags. I complained about the gas mileage on my 900 and then I found the front disk brake was dragging and the front wheel bearings were shot and very rough. I rebuilt the front caliper but I believe there is still some drag there. Wheel bearing replacement went with out a hitch.

While I was working with the front wheel, I decided to service the triple tree bearings because I figured they had not been serviced since 1975 when the bike was built. What a frigging mess that was. Little grease and plenty of rust. At least one race would have needed replacement. Solution? All Balls. I put in All Balls tapered roller bearings in the triple tree. What a difference. I'm thinking of putting All Balls in my 09 Councours 14's triple tree. Some may disagree but at this point the 900 just seems to turn better after installing the All Balls. No little 1/4 inch ball bearings rolling around either. Plus the tapered bearings just seem a lot more robust in my mind.

Z1Driver wrote: ..... I put in All Balls tapered roller bearings in the triple tree. What a difference. I'm thinking of putting All Balls in my 09 Councours 14's triple tree. Some may disagree but at this point the 900 just seems to turn better after installing the All Balls. No little 14 inch ball bearings rolling around either. Plus the tapered bearings just seem a lot more robust in my mind.

Amen! I installed All-Balls tapered roller bearing in my KZ650-C1 several years ago - night and day difference! Tapered roller bearing have more actual bearing surface than ball bearings so they last longer, feel smoother, etc. Ed