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Old 08-30-2011, 06:47 PM   #88
Old Traveler
Joined: May 2008
Location: Georgetown, In / Costa Rica
Oddometer: 699
Dave thanks for taking the bait. I thought of writing more in my question but wanted to leave enough for your grand explanation. Every time I try to inform the troops I get flamed. BTW with the stock IMS tank and IMS supplied petcock, cap and a loop in fuel line my DR would run to the last once or two in the tank running full throttle down the highway, experienced. I would expect yours to do the same but you do have a different petcock.

Ride safe and have fun!

Originally Posted by motodavid2000 View Post
Tom -

Good to hear from you. Hope that you are enjoying Costa Rica.

No, you are not under any misconception. From my classes back at Purdue University so many years ago, the head pressure of the fuel is the delta in fluid levels. The issue becomes flow rates to the carb from the tank, combined with dropping fluid (fuel) levels and reduced head pressure.

Without spending time calculating some theoretical point, I am sure that the carb can be "starved" of fuel when a combination of low head pressure (low fuel levels) and high flow rate (fuel draw) causes insufficient fuel delivery to the carb based upon engine needs. I think that this would be experienced at very low fuel levels and higher loads & revs on the engine; perhaps exagerated with high altitude operation.

My general take is that the carb should not be starved of fuel when it is at least 25% or more full of fuel, operating at any reasonable engine load.

My fuel line loop below the carb inlet would cause a loss of a small amount of fuel not being available for the engine, and possibly an air bubble to form. This would be an extreme case, and the engine would / may be starved of fuel before that time with low head pressure and higher engine loads.

I don't think that the engine would starve at idle until the fuel reached the level of the fuel tank petcock intake.

Getting ready to make a few more mods to the windscreen and instrument panel supports. Will post some pics when the work is done.

Also, still resolving fork stroke / tire bottoming probabilities - have not disassembled the forks yet and want to ride it first. If I need to change springs, I will check fork stroke / bottoming stroke and also change springs at the same time.

Take care - Dave
DL1000 '05 black
DL 650 '06 Red
DR650 '07
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