GT750 Miles Per Gallon

[Vintageman]

Hello,

Sure this has been asked before, so forgive me in advance for asking it again

What have GT750 owners been getting for fuel economy (i.e Miles Per Gallon)?

I took my 1975 GT750M recently and got only 30 Miles Per Gallon. It was not all highway, some back road, I was riding 2 up, but not running too hard either. More small throttle opening than large during the ride. Noted very heavy exhaust fumes lwhen small throttle opening. Maybe more than normal for a two stroke maybe not.

I put the air jet mod (most likely small size air jet too) per Suz bulletin for "Bucking". If others are seeing mid to high thirty miles per gallon for example maybe I may be too rich low speed circuit. I am pretty sure I had pilot fuel screw set to factory (forget now what the is) and correct pilot jets for the year. I may try increasing the air jet size a couples steps. Anyone do this mod and see a drop in MPG?

Thanks

[jabcb]

Went for a ride on my red GT750M hilly rural PA recently.
Still breaking in a fresh rebuild so that might depress milage a bit.
(Am following break-in instructions in manual.)

Got about 25 mph.

I don't know how they got those good mileage numbers in those old bike magazine tests.

[Vintageman]

jabcb.

You have two 1975 GT750? Both the same?

Did you do the air jet mod or did you leave it stock?

Thanks

[yeadon_m]

About 30mph with spirited riding is reasonable. More on a steady-throttle highway cruise, even less if thrashing it around roads with lots of acceleration and braking. Been from brim full to on reserve in 89miles once. A fun ride

Mike

[Barry S.]

I can go 125 to 130 miles highway before reserve on mine, maybe slightly better if some slow riding mixed in.

[Alan H]

Increase your MPG instantly!
Buy fuel in Imperial gallons!!!

[jabcb]

Increase your MPG instantly!
Buy fuel in Imperial gallons!!!

Yes, but our regular E10 gas is around $3.40/US-gal & the extra-special 91-octane ethanol-free gas is $4.99/US-gal.

[Alan H]

Ah, I see now. The bl00dy garages round here don't take $$.

Drat and double drat.

[Coyote]

Yeah, times have changed. My 2013 Nissan Sentra has a real time MPG gauge. It is consistent at 33.3 MPG around town and 40+ the couple of times I had it on the highway.
ISIS is underselling OPEC. 87 octane with 10% spirits is currently $2.98 per gallon here.

[Vintageman]

I am thinking the air jet mod stole a tad of my potential mpg. Or at least made my small throttle fumes heavy … anyone else do this? But, sounds like 30 mpg not too bad and maybe low 30s if pure highway

The fumes of unspent fuel are tremendous ... you sit at a traffic light, running, too long on a humid no breeze day (ias it was) you may pass out from asphyxiation. I don’t care myself but, self-conscious about others. And that day my wife was on the back She was not happy. Jeeze I miss the 70s. All Vehicles were horrible and if you were a kid in a car everyone smoked even on a winter day all windows when all windows were up tight!

As I said before it ain’t just the blue smoke that pisses people off about two stroke. I hate being followed

Well what did the period article say they got for mpg (I’ll have to re-read)… I may pull out that air jet or increase its size. Or maybe the filter has too much oil (was NOS and had oil already on it).


Thanks

[GT750Battleship]

Hi,around 30+mpg on my '76 GT750A,when I'm having real fun...it can drop dramatically
Cheers,
Roger

GT750A

[T350guy]

I did the air mod on my 77 GT 750.
When the bike was first on the road this year it had been sitting since about 1990 in storage by the previous owner.
Mileage was terrible but as the lies went on the mileage is up.
Steady riding with some town work get's me about 40-44 mpg and the needle clip is in the 3rd notch.
So approx 125-130 miles to a tank before reserve depending how much I fill it.
Ian

[jabcb]

jabcb.

You have two 1975 GT750? Both the same?

Did you do the air jet mod or did you leave it stock?

Thanks

Was on the red GT750M. Its stock except for H4 headlight, Newtronics ignition, and modern rectifier & regulator.
Rebuild included new top end, crank seals, new stock air filter & new intake boots.
Don't know if it has the air jet mod.
Was the first ride were break-in instructions allow the use of 5k rpm.

The 25 mpg could be off since is a single tank estimate.

The gray GT750M is modified.
Has GS cast wheels, rear disk brake, GS forks+brakes, vintage chambers, Newtronics ignition, and pod filters.
Has new top end & crank seals done by the PO.

Here is a pic of them from a while ago.
Have since added the tank decal to the red bike & fixed the fork ride height on the gray one.


Pic from the recent ride where I got 25 mpg. Looks much better with the tank stripe + clear coat.

[Barry S.]

Sounds like your fuel mixture screws may be open too much. If it is it can blubber and soot up the tag and tailpipes. I think a 1/4 turn open is correct.

[Vintageman]

Barry S

You may be correct. I did set it to stock. I think the 74 was different the 75 and up likeone wa 3/4 and another 1/4... I forget and think I have to check this again as well. Question need for air jet mod

T350Guy

Like Jabcb my bike has new top with OEM OS pistons rebuilt crank, maybe 250 miles since.
Sure runs well, has a lot of low end grunt (for later model) and good top end. I did increase teeth count on rear sprovket by 2 over stock (which was very tall gearing versus previous years if i understand)

jabcb, what does your grey 75 get for mpg? I have jemco but stock air box?

I am third clip and needle jets were real nice (not pitted for corrosion). I am not sure i needed to do air jet mod, but did it anyways. Maybe yours needed the air jet and if you don't it become too rich

If I am too rich I keep harping low speed circuit for that day I really did not use a lot of large throttle. I could have enlarged needle jet orice even thought not pitted.

I don't think Needle Jet are available anymore?