83GS550E Sprocket Size For Increased Speed/Lower RPM?

[GQROD]

You are right that's what i thought but i think it may be my riding very short distances wasting more fuel, should i double check my float heights as mentioned earlier? or should i change the mix screws and run a little leaner?

I may have to pull the plugs and see where i'm running rich.

[p_s]

My truck gets better mileage, you should be going more than twice that far on the gas.

Something is wrong.

It's supposed to be 3.9 gallons until reserve, but it's actually much less. But you can squeeze a little more than 4.8 gallons into the tank. I leave my GS550ES on reserve all the time, but that's also because I have a stupid cover over the petcock that can't be opened with gloves on. And the fuel gauge works pretty well.

[GQROD]

It's supposed to be 3.9 gallons until reserve, but it's actually much less. But you can squeeze a little more than 4.8 gallons into the tank. I leave my GS550ES on reserve all the time, but that's also because I have a stupid cover over the petcock that can't be opened with gloves on. And the fuel gauge works pretty well.

I see what you mean, i'll have to do plug chops and see if i'm running richer than i thought when i tuned the bike with the color tune.

I don't have a cover on my petcock and have judged that when the needle gets to a little below half on the guage then i have to swicth to Reserve or it sputters. I'm on reserve now which is why i've noticed the consumption has not gotten very much better.

So either my float heights can be lowered or my mixture screws need adjustment. I'll do some more riding and see what i get.

Thanks everyone for the advice.

[p_s]

So either my float heights can be lowered or my mixture screws need adjustment. I'll do some more riding and see what i get.

Actually you never told us what mpg you get--unless you ran your tank dry and only got 125 miles. My speedo is dead on, but I don't know about the odo, and I normally get 42 mpg at ~75 mph. Short trips in town--more like 30, but my commute is only 2 miles.

[GQROD]

I'm running the tank dry now and i'm at below half tank but not on red yet, with 84 miles on the odometer, don't really know how accurate it is i'll have to use the gps to track speed etc to be sure. 125 miles divided by 4.8 gallons about 20 miles to the gallon. But i have only done short trips with still relatively long warm ups about 4 minute warm up times.

[tkent02]

125 miles divided by 4.8 gallons about 20 miles to the gallon.

Should be well over 50 mpg, all else being good.
Ignition timing, valve clearances, compression all good? Brakes dragging? Exhaust clogged?
Lugging it around at 2,000 rpm? Fuel dumping out on the ground?
Something is amiss, probably a few things.

[p_s]

I'm running the tank dry now and i'm at below half tank but not on red yet, with 84 miles on the odometer, don't really know how accurate it is i'll have to use the gps to track speed etc to be sure. 125 miles divided by 4.8 gallons about 20 miles to the gallon. But i have only done short trips with still relatively long warm ups about 4 minute warm up times.

Keep in mind gas on the right side of the tunnel can't get to the carbs unless you lean the bike over.

[GQROD]

Should be well over 50 mpg, all else being good.
Ignition timing, valve clearances, compression all good? Brakes dragging? Exhaust clogged?
Lugging it around at 2,000 rpm? Fuel dumping out on the ground?
Something is amiss, probably a few things.

All good points,

no fuel on ground, or in crank case.

Have not checked timing with a light though the marks are correct with the cams though the cam notches are NOT directly opposite each other one is slightly off, i'll have to check the cam timing when i get a timing light to ensure it's not contributing to this.

Exhaust is original , i have not noticed excessive back presure but you make a good point for me to check this.

I'm over 2000 RPM when riding, at least 3500 RPM

Valve clearances done to .13mm the largest clearance allowed in the manual.

Brakes could be dragging on the front but i did not notice any smoke or exccesive pulling to one side.

Gotta check my compression i did not have the 12mm adapter for my compression guage.

[GQROD]

Keep in mind gas on the right side of the tunnel can't get to the carbs unless you lean the bike over.

Thanks this i did not know that, definetly will help if i run out of fuel leaving the petcock in Reserve.

[tkent02]

Valve clearances done to .13mm the largest clearance allowed in the manual.

What manual are you using?

[GQROD]

I'm using the factory manual for the 83 gs550E

[Scotts]

I have an 86 with the stock sized sprockets and run about 40 MPG around to work and back. 7 miles 1 way with about 5 traffic lights each way. I ran a trip out and back to run along about 70 and got about 45. Valves set and new plugs, It runs fine for me so I have not messed with the carbs.

Scott

[GQROD]

Thanks scotts, it's good to get a reference point so when i start going through the bike again.

[GQROD]

Update

Just an update ......By far the best mod i have done yet.

My fuel mileage has gotten much better 35-40 MPG as oppossed to the 20 i got before ( perhaps due in part to weak spark from old wires which i have since snipped at the ends ), and more importantly i can now cruise at 4000 RPM at 60-70 MPH depending on headwinds.

NEW
Front 16T
Rear 43T

OLD
Front 14T
Rear 48T

This is definetly the max for this bikes engine size so those considering the swap should go either with just the front upgrade or go 15 / 44 to have enough torque to wind it out to redline.

For my style of riding this set up is perfect for me. Thanks everyone!

[Old Colt]

Umm, I always got at least 55mpg on my GS550 ES and with one tooth larger on the front it was up in the low 60s.
You sure yours is running as good as it can be?