Evo160K

After having read the excellent topic, "Setting DHLA Dell'Orto Dellorto Float / Fuel Level", by TheShaman, I'm attempting to adjust the fuel level in the DHLA40 on my Harley-Davidson. Obviously, it was necessary to block the bike straight up and level like it would be on the road. Following the instructions in the article helped a great deal, but the fuel is still below 27 mm (as best I can measure and that's an issue). The float is 8 gr. and the float height is already at 12.7 mm, that's less than the article suggests as an initial setting. I believe the engine still needs more fuel at WOT, it's running out. The needle/seat is a 325 Turbo. The article states fuel level can be measured through the main jet stack hole but it can be hard to see, etc. So here's the question: would my fuel level measurements be more accurate if I took a clear glass tube, put it in the main jet stack hole, marked the top of the central tower on the glass tube, put my finger on top of the glass tube to capture the fuel and then measure from the top of the fuel in the glass tube to the mark on the glass tube? Thank you for your opinions.

This pinned topic by TheShaman helped me considerably: http://sideways-technologies.co.uk/forums/index.php/topic/1048-setting-dhla-dellorto-dellorto-float-fuel-level/

Are you having a fuel issue that requires a Grose Jet? What's in the carb now and how is it running? I've used a grose jet in the dhla40 on my 97" Harley.

Update: Considering Nick Jones concern about adequate fuel pump supply from a vacuum pump (post #3), I've installed a Huco electric demand pump to insure adequate pump pressure at WOT. The lean issue still exists, but I feel more confident with the electric pump. For years this street/highway bike has had a tendency to go lean as it starts up even a slight hill. On full acceleration through the gears it runs out of fuel and has to be coaxed to keep from dying. I know it’s a lean condition because there is an air-fuel meter on each exhaust pipe that indicates so. The intake manifold has individual runners. After trying many jet combinations, needle/seats and currently the Huco electric demand fuel pump with no success, I’m beginning to suspect this condition is related to the float/fuel level-----------too high, too low, sticking, wrong weight or ? The float is currently set at 15 mm with a 25 mm droop. For what it’s worth, occasionally there is a single hiccup in the engine when transitioning from downhill to uphill. Are you able to point me in the right direction? Thank you very much.

Mr. Jones, Thank you very much for your comments. I appreciate them. The venting I can check by cracking the fuel cap when the stumbling presents. To check the fuel line size, (I believe it's a 1/4" id), I can bypass the fuel pump and static check fuel flow through the line by measuring the free flow. With that number I should be able to calculate how much horsepower that flow will support at wide open throttle rpm. I think that will tell me if the fuel line is sufficiently sized to the pump. Does that make sense to you? Regarding flow through the pump, you're suggesting there may not be adequate pumping at wide open throttle to deliver sufficient fuel because the pump more or less stops working due to low vacuum. I hadn't thought of that possibility. Do you have a thought on how I can test to see if that is the case? Thank you.

Would you please help with a problem I'm experiencing? On sustained high speed runs to approx 4800-5000 rpm and brief WOT acceleration through the gears, the engine begins to stumble like it's running out of fuel. When I back off the throttle the engine will slowly pick up again. The engine details are 1606 cc (803/ cyl) 36 chokes 05 main emulsion tubes 155 main jets 190 air correctors Grose jet (fuel needle and seat) Dell' Orto pulse fuel pump - I calculate it will support approx 100 hp 03 idle jet holders 60 idle jets Thank you very much.

Couldn't believe my eyes when I came upon your remarkable website. I had no idea there were so many knowledgeable and enthusiastic Dell'Orto fans in one place. For the most part dellortos are not that popular on Harleys in the United States any more, perhaps they're too much of a challenge for most to tune. Admittedly, I had major problems for several years trying to use harley's traditional gravity fuel flow. From a full tank to a half tank or every 10 degrees change in temperature required an idle mixture screw adjustment. Finally, the very good people at Dellorto.uk put me on to the dellorto vacuum, pulse pumps and provided excellent advise and parts. Since that time I've had very satisfactory results. I've also used many of the tuning books, including Jack Wagner's book on tuning dellortos for harleys. My question: since I'm always trying to learn and considering the topic of my post may not be appropriate to your website, are you able to direct me to a comparable site or source that is? Thank you very much.