bad fuel millage on road bike build?

mr42ndstblvd · Nov 12, 2013

i helped build an old road bike for a friend it has 26x1x3/8 tires rear 3 gear with a 32 tooth sprocket sandwich hub 70 cc china motor from ebay ebay upgraded carb high compression head chambered exhuahst ngk plug and of course the loaded spring tensioned idler with gear and its also bolted into the frame also the studs on the china gas tank where removed and replaced with larger studs and they where brazed back in and the tank was coated with por15 to seal it dosent leak at all and no worries about it leaking

the problem is it burns thru gas like crazy a full tank lasts 65 miles at best and its just a stock half gallon tank any ideas tips?

dodge dude94 · Nov 12, 2013

It's new.

That's your problem. You're running break-in gas that should be around 24-32:1 oil/fuel ratio. It's going to suck gas until you're off break-in.

crassius · Nov 12, 2013

half gallon tank lasting 65 miles is 135 miles per gallon - not bad without knowing weight of rider and hilliness of terain

maniac57 · Nov 12, 2013

Sounds about right to me. Wait till it's fully broken in before jetting it. Lean it out and swap to a 36 tooth rear sprocket and you can easily get 150+mpg

motorstumpy · Nov 15, 2013

I only get about 90 miles to the gallon at this point. I have maybe 400 miles on it. My true fuel consumption is still a bit if a mystery however as I can't seem to keep my tanks from leaking. I am visiting my brother, who has a fully epic shop over t-day and am hoping to make a custom tank or re weld at least one of my Chinese tanks (always the studs). The screw on the side of my card which I would think adjusts the fuel:air mixture doesn't seem to have any effect, at least at idle. Ant pointers would be appreciated!

BoardTrackBomber · Nov 15, 2013

Fellow Okie!

As other have said, your mileage doesn't sound too far off from where it could/should be.

1. Newer engines will consume more fuel mix until the rings fully seat into the cylinder bore.

2. Tuning the carb is pretty much mandatory.

3. The stock plug and plug wire in the kits are garbage and could lead to fuel waste and inefficient combustion.

4. I ride my bike at WOT frequently, which of course will lead to more fuel consumption than if you were just putting around slowly. Something to consider.

I wouldn't worry about it!

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bad fuel millage on road bike build?

mr42ndstblvd

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dodge dude94

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crassius

Well-Known Member

maniac57

Old, Fat, and still faster than you

motorstumpy

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BoardTrackBomber

New Member