View single post by Bob 13902
 Posted: 04-21-2012 10:18 pm
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Bob 13902

 

Joined: 04-05-2006
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I seem to be thru all my issues with the Dell 45's - here's what I did/found...I've attached a pic to help with the explanation... (1) The hesitation was caused by low float level. I did not change to the "richer" idle holder jet. To get the right float level with the 7gram floats that I have, they need to be set at 10mm (not 15mm per Hammill). The other important thing about the 10mm measurement is that it needs to be the same at any point from the top surface of the float.

I bent the floats so the tops were "level" with the carb top at the measurement point (so the measurement dimension is the same to the gasket surface anywhere from the float top - I find it interesting that I've never seen a float setting procedure that addresses this. The floats were far from even before I did this and the effect on float level was 4mm). I set the floats targeting a bowl level of 27mm (distance down from top of float bowl) at the centerline between the main and idle jets. With the tilt of my carbs, the measurement on the main jet side was 27mm down and on  the idle jet side was 31mm down. I was going to make another adjustment to get to 25mm and 29mm, respectively (so the average was 27mm), but decided to save that for another day since engine performance is strong throughout the RPM range where they are. At the current setting, the 7g floats measurement is 12mm (I also readjusted to the appropriate 25mm droop). However, to get the 27mm average, that makes the correct setting for these floats at 10mm - which is where I'll put them next time I open them up again.
(2) Fuel leakage into the K&N air cleaners was caused by not using the correct trumpet gasket. Fuel was getting into the annulus between the venturi and barrel (likely at the joint between the venturi and choke). As a result of air pressure distribution and/or capillary action, it had a path to K&N's.
When I had installed the trumpets, I chose not to use the rebuild kit gasket because it had a smaller OD than the venturi (and trumpets) and would disrupt air inflow...which I wasn't keen on since maximum HP increase was a goal on this rebuild. Rather than trimming it, I had decided to install the gaskets provided with the K&N filters only since they were larger than the trumpet inner diameter. The problem is that they are the diameter of the barrel so the annulus (where gas was leaking from) had a free path to the K&N's...and I guess the aerodynamics got me. I did check the venturi to barrel clearances which are supposed to be 0.004 mils and they were ~right. The venturi and choke were both held tight together once the venturi positioning/lock screws were installed. I also verified the fuel pressure at the carbs - which was fine at 3psi and the new inlet valves seal fine at the 3 psi.

Attachment: Dell45-Float Set_JH-Apr2012.jpg (Downloaded 108 times)