why the crappy gas mileage?

I've heard that xj650s even when in great shape only get low 40's at best. Is there any specific reason for this? Any ways to increase it at all? 40 is better than cars get but not by all that much.

 

Sounds about right for the displacement, weight and technology. Shed a few pounds of steel and aluminum, improve the fuel metering system, punch the cylinders out a little and you should reach your goal. How's that?

 

On in my case - loose 20 pounds, tuck in on the tank and put a small windscreen on.

I get 34mpg +/- 4mpg.

Check the condition of the fuel fuel, carb, and exhaust system. Leaks and wear will degrade fuel milage - as will improperly tuned carbs.

 

im not for sure of my gas milage because i dont know how big the tank is i know that on my 82 maxim 750 i can go 100miles on a haf a tank according to the fule gauge mind you i guess ill have to figure it out next time i fuel up

 

How to check your fuel milage on any motorcycle:

Next time you stop for gas - make sure you fill it to the neck. Zero the odometer.

Everytime you stop for gas after that fill it to the neck - and write down the odometer. Zero the odometer. Divide the miles by the gallons and you've got your answer. The only way you can mess it up is by not zeroing the odometer or not filling the gas tank to the top. If you stop early and fill a half full tank it won't matter - you'll have gone half as far on half the volume of fuel.

Personally - I like keeping a fuel log - it gives me an idea what the bike is up to. Long term changes in fuel milage indicate changes in the engine.

Cheers,
woot.

 

New I got about 49 mpg on my Seca. But my Maxim after a carb cleaning and sync has only gotten 46mpg. This has settled down to about 42mpg. I guess I got good gas in Texas and since it was all highway miles with a good warm engine it was all in my favor. Combination city/hwy is about 39mpg.

 

Last month i was recieving 40 mpg now im down to about 37 36 range. My driving really hasnt changed so it must be something with the bike.

 

Don't forget that air temperature can affect our gas mileage since our bikes are carbureted...

 

I run my tank until I hit the reserve and get gas, fill her up.

I get about 100 miles and thats it.

Probably will be better after getting it tuned @ the shop.

 

I have a recorded 52MPG on my '82 650 Maxim - but that was when I first got it... Since then, I've only been getting from 35-45 MPG - depending on riding style & tuning... I can probably do to have some more accurate tuning - but I'm happy with what I have at the monent.

Rex S.

 

I have a 81 XJ 550 Max and I get between 45-60 mpg. I'm thinking of doing some gear changes to increase my MPG. (given the greed at work in the "powers that be" today)

Kelly

81 XJ 550 Maxim

 

what would be optimal gas mileage for a 82 750 seca? You guys that are reporting gas mileage in the 50 mpg are running smaller bikes. What are some steps that i can do to improve gas mileage.

 

Best I ever got on my Seca was 49. I would think that with 20= years of age 40 to 45 would be ideal.

 

On my '82 650 Seca, I seem to be floating right around the 43 mpg mark. I need to re-synch the carbs, but otherwise, it still beats the 18 that I get from my truck.

 

You are a riot Sno! I just trimmed off 15 pounds myself. Feels better too (hey, my old jeans fit again too).

 

I'm in the same boat SnoSheriff... I'm a fairly solid blue liner now, trimming 30 lbs off would be a good idea - and certainly make it easier for the bike to pull me around.

The next best thing to do is become more aerodynamic - I'm still working on shrinking my shoulders

 

hey guys ive got a 650 and i got 3.5l/100km on the weekend. i was amazed the bike was running a bit lean so thats why it was so low, all freeway pretty much sitting on 100.
the bike is in at my tuner getting jetted and synced atm. cant wait to get it back :lol:

 

When it was explained to me:

There are two factors that affect fuel mileage on a bike, those are
1. aerodynamics.
-despite what one might believe bikes are not very aerodynamic especially the maxim with no fairings, there are many paths for air to go through, therefore create lots of drag. There was a teardrop shaped 2 wheeled vehicle with a 300cc or so engine, built in europe that was getting close to 80-90 mpg on the highway sumply due to it's shape.
2.Engine.
Generally motorcycle engines with a displacement larger than 400cc are meant to be recreational vehicles ergo gas mileage is sacrificed for all out performance. The engine was built around performance. Not to mention the giant fuel line leak we call a carburator is not the most efficient mode of obtaining an ideal fuel air mixture.

Point being if we all had teardrop fairings and efi port injected engines there's no reason one couldnt see up to 100mpg from such a vehicle.

Very practical but where's the fun in that? I'll stick with my parachute bike.

 

I just did a run of about 550 miles. Averaged 40mpg US. I had to do some fancy converting. Liters per Km to miles per Imperial gallon then to US gallons. My butt is usually sore when it's time to fill up again! '81 550 Seca.