MPG and modifications

[inxs]

- MPG and modifications?

- been thinking about mileage, and the corresponding affect of modifications to the stock setup...inlet, outlet, head, cylinder, gearing, frame, riding style, etc

- any thoughts? or personal experience-records?

 

[pyrocentric]

I've never considered it, but I guess I would gear it high, port the head, run the smallest jets that don't blow holes, and go on a diet. I guess a fairing couldn't hurt either. The bike is heavy, it's not going to be a gas-sipper.

 

[grizld1]

I've seen some mileage numbers racked up that just shouldn't have happened, and the only thing I can attribute them to is meticulous tuning. A couple of years ago at the Smoky Mtn. Rendezvous our rally coordinator turned in a carefully measured 60 mpg over a mix of higher speed highway and twisty mountain roads that included US 129 (the Tail of the Dragon)--no chances for steady-throttle hypermiling techniques there! To really cork it, his XS650 was set up with K&N filters and 1-3/4" pipes and megaphones from Omar's--hardly the optimal setup for an otherwise-stock engine! Apart from seat and foot pegs (Raask rearsets) the machine was stock. The man is a career motorcycle tech with around 40 years of experience and multiple certifications. I can't help wondering what kind of fuel consumption he'd be getting with stock pipes and airbox--the pipes and pods can't be helping in that respect.

 

[jay760]

My 760 gets about 35 to 40( if I'm lucky) mpg, I've got a 2 gallon tank and filll up every 60 miles

runs an 18 tooth front sprocket

760cc with 34mm dellortos

But it does tend to go everywhere at 80mph, and get abused alot.

 

[pamcopete]

Well, with a stock '81/H, stock BS34's with 135 mains, EMGO 27" mufflers, paper filters, 30 PSI in the tires, 33 tooth rear sprocket, moderate temperatures, windshield, 190 lb rider, PAMCO ignition, Iridium spark plugs, 89 Octane, average 55 MPH highway riding with a 30 mile out and in ride (60 miles total) with a few stops I managed 65 MPG.

 

[Dogger]

My bike is bored .30 over, 36ml mikunis from P Bertaut, 1 3/4" headers with taper tips. It's received a severe diet from frame to wiring and has stock gearing. I get in the high 40s and that's riding it as hard as she goes.

 

[xsjohn]

After 40+ years of this......a short jaunt down the express claiming moderate temperatures on the cylinders...would like to be there to see all that....I've heard so much BS on this subject ..LOL

 

[XS1961]

Standard bores on mine...
With Kawasaki GPZ 500 carbs fitted I get 45-55mpg(much the same as standard carbs)
With the 34mm roundslide/vm's I get 28-40mpg...

 

[pamcopete]

xsjohn,

The moderate temperatures refer to the ambient temperature, not the cylinder temperatures...get a grip, john

 

[retiredgentleman]

Last summer my buddy (on his 1980 XS650) and me (on my 1978 XS650) went on a trip up into the mountains west of Calgary. Speeds were 90 to 110 km/hr, mostly 100 km/hr. Went from 3400 feet ASL to 7200 feet ASL. We covered about 350 kms.

I have 17 front/33 rear sprockets............stock exhausts.........stock BS38 carbs........stock airboxes and filters............Pamco Ignition.............Accel coil.
I got 55 MPG (US gallons). If we had travelled on flat land, I suspect I would have got even better milage, but I'm quite happy with that milage. You need to have your carbs tuned, air filters clean and good ignition.

My buddy always needed more gas at fill-ups. His carbs need to be tuned and he needed new air filters. His bike has BS34 carbs and stock TCI ignition, with 34 rear sprocket.; I didn't calculate his milage but I think it was about 45 MPG.