How to up fuel efficiency

[alexanderfoti]

Just having at think.

On the 400cc yanmars, whats the best way to up the fuel efficiency?

Obviously an oil tight gearbox with thin oil would be good, rather than using thicker oil to mask the oil leaks, causing more drag.

And removing the fins on the flywheel as they arent needed when the engine is used in a motorbike scanario.

Any other thoughts?

[coachgeo]

Similar thread in here discussed that improving efficiency of air moving around the bike was the number one thing to improve mpg. (Fairings etc.)

[XLerate]

Reduce parasytic drag wherever possible: wheel, hub & axle bearings super-lubed with best available synthetic lubricant; highest safe tire pressures; least possible residual pressure in brake lines; least possible drag of brake shoes or drums when not applied. Adjust injection pump injection timing to most benefit normal operating conditions: retard for better bottom end, advance for better top end. Spoke tightening to straighten wheels and prevent wobble or shimmy. Best chain size, type & sprockets with lowest drag coefficient for economical operation.

[alexanderfoti]

all lots of good input!

It should bode well for the new bike im building then, as it has full fairings, that should help to reduce some of the drag.

I am going down Tim's belt drive route as well which should be more efficient than a chain, and once I replace all the seals in my box, it should be pretty oil tight, so I can use a lighter oil. Interested to see what I get!

[XLerate]

After your fuel efficiency mods and upgrades you can focus on setting up the engine's fuel pump timing, injectors, gear ratios to run in the 'sweet spot' for your most frequent driving conditions.

I've put a Cummins 4BTA w/ NV4500 5sp, DANA 60HD 4.1 rearend in my big old '67 Dodge truck [7,200 lbs] and was getting 32 mpg under adverse conditions! ALL I DID was get talked into 235/85-16 tires instead of the former 235/75-16 tires and my mileage went to the dogs! Huge, gigantic difference because I do mostly mountain driving. Learn from my mistake and get those numbers just right: it's all about gears, Gears, GEARS!

[oldbmw]

never be seduced into raising the gearing, all that helps is top speed downhill.
check chain alignment and make sure they are well lubricated, but the biggest variable of all is the hand on the throttle.

also anticipate, using brakes is wasting energy so slow up on the throttle in plenty of time.