lectron problems again

i put my bike on the dyno yesterday and was hoping to be able to report to you guy's the final numbers ,but i guess i can't do that just yet as i have run in to a small snag,. it appears that my fuel system can't keep up to the needs of the engine when i hit about 5500 rpm the carbs run out of fuel it is something to see i have a daul feed pingle race petcock on it as well as a2 into 4 pingle filter with 5/16 lines going to each carb and it still can't supply enough fuel the actually run dry at half throttle the numbers i got up to that point are very promising 159ftlbs of tourque and 127 horsepower but that is at half throttle on a 4th gear roll-on do any of you guys have any experiance with using a fuel pump with 40 mm lectrons and if so what type and did you also run a regulator in line and what pressure did you run it at. inquiring minds need to know as i have basicly no experiance with these big carb's and this is the first big block i've ever built it is a 1393cc with a j head and the pistons are mtc 14.5-1 that are matched to the j head plus the head has been shaved .050" i'm running j rods and i have about .005" positve deck heights. any advice would be greatly apreciated. thanks in advance

Some thoughts from the peanut gallery K.I.S.S. department. :laugh:

Is fuel tank cap adequately vented?

Has flow volume from petcock been timed and measured with engine off and fuel tank cap open? For example, how fast does a quart of fuel pass through the petcock?

Could repeat same flow test at exit from inline filter to assure filter is not impeding flow volume from petcock.

Compare results to volume required at wot.

Given ample cap venting and clean fuel inside tank with no cloging of pick-up screens, and highest possible flow volume through a single petcock. If flow volume remains insufficient from petcock, am wondering if adding a second petcock might be feasible.

Then again, perhaps the "mainjets" are too small (or adjustable tapered jet needle positions set too lean). What are the plug readings above 5500 rpm?

Good Luck!

i'd try to read the plugs past 5500 but it wont go that high it keeps running out of fuel and i'll try the cap open wheni get on it tomorrow. i have never seen anything like this my self it is wild.

Give Paul Gast of FAST BY GAST a call. He is the GURU Of all things
Lectron related. Ran the same setup 20 years ago as there are no main jets in the Lectrons ,If I remember correctly
raising the needles should solve your problem.Never recall anyone needing a fuel pump.

PUFF DADDY
RUSSELL PERFORMANCE MC

Old guys think slow. Just remembered check your float heights could be running out fuel due to lack of fuel level
in the bowls.

float heights are perfect according all info and ive got the needles at 1.80" any more than that and it runs fat with the heights i have now it idles nicely at 2000 rpm and the ega is showing right around 14-1 air fuel so it's pretty good there as soon as it hits 5500 iit goes dead lean the dyno's ega goes to 20-1 air fuel and it pins the gauge as soon as i hit the magic number of 5500 every time ive tried raising the needle 2 turns up and it did excactly the same thing.

u should be able to get plenty of fuel through that pingle. i ran my 1327 with rs34's with 135 mains no problem. i have a nock off 5/16 fuel petcock with an inline fillter. i ran 1 line only. wide open throttle and hange on. i know mine is a bit smaller than your but i had no isues. my frend has 32mm flat slides on his 1428 motor with a pingle.
I think Plumman is on the right track.check the flow and vent.
Run it by the boys at drag bike .com. they run those big babies all the time.

I agree on the venting if the floats and needles are right. Try it with the fuel cap off.

yes i'll try that. i never even thought of that i was just so freaked out about the tourque numbers i never even thought of that

Is a different shape metering needle available to enrichen mixture at higher throttle position?

Lectron Needle Chart

Most probably all this has been long since already considered and addressed, but here goes anyhow just in case. :lol:


Am wondering if there's possibly an issue with float bowl venting so as to create a vapor lock situation.


Also found the following while plonking around.

The Lectrons are quite unique to jet. You must first understand that Lectron uses a single threaded metering rod that is tapered. This rod takes the place of a air screw, pilot jet, needle, and main jet found in a Keihin or Mikuni. This one metering rod is equivalent to about 10 main jets. For idle and low speed tuning you turn the rod in to richen the mix or out to lean the mix. For Midrange tuning you read the 2nd number on the rod. If you want to richen the midrange up you put in a rod with a bigger 2nd number or if you want to lean it out you put in a rod with a smaller number. (ex. #5-2 rod is to rich in the midrange you would replace it with a #5-1 rod).

For top end tuning you use the 1st number on the rod and the Powerjet. If you find that your top end is to rich you can drop down the number on the Powerjet. If this does not solve the problem you will have to change the rod to the next number smaller. (ex. #5-2 rod is to rich on top you would replace it with a #4-2 rod and readjust your powerjet). One small note on the rod also is that the flat side of the rod must always face in towards the engine. Jetting the Lectron for the first time can be a little troublesome as it is so different then any carb out on the market today. But once you get used to doing it you will never want to jet any other carb again.

Good Luck!

they are definitly an amazing carb and probably one of the easiest carbs to work with every change is very noticeable i am using the 2-0 needles and it carburates very cleanly until i run out of fuel so i know they are not the problem so i'm going to pull the cap off tomorrow and try that