S&S E-body 50mph - 60mph's in 4th gear Flat spot !

[Motorcyclemike]

I have been fighting a flat spot in my shorty e body for the last month....i have considered drilling out the main jet air bleed to .048 with a number 54 numbered drill bit......and if i have to i will drill the jet out and tap the hole so i can use a S&S main jet.....has any body else had the flat spot issue.....i don't want to go to the "Thunder Jet" as long as i can do the fix very simply by drilling the jet out.......its a .040 hole now.
Any one have the S&S Bulletin on this?
I am running a 295 intermediate and a 70 main jet.
Thanks to all who help.
Mike*
55 to 60 miles per hour is the cross over point in 4 th gear with the "Intermediate jet" to the main jet....thats the area i am fighting !

[old1955]

G'day Mike,

This is what S&S say.

To test the Main Jet, do a high gear roll-on from 50-mph to 70-mph. If the engine back fires or breaks up in the carb, increase the Main Jet size .004".

"If the engine is flat or will not accelerate, decrease the Main Jet by .004" ...... This may be your bit?

Pete

[Motorcyclemike]

I have done the WOT Roll On!.....from 50 to 75 mph....that was OK......No hesitation or pops it got to 75 mph like a Stripped Ass Ape!
Problem is a slow....roll to 60 mphs from 50mphs.....its sortah has hesitations and carb will sometimes "POP" one time along that 50 to 60 mphs range from 60 UP is OK !
I am running.....2 in to 1 and a long t-pipe with a stock type 74 muffler.....I have Googled the problem and thats where i found out that the E bodys before 2004 had a fixed air bleed for the main jet and the carbs before had a fixed air bleed jet......the filter is a large new fram and gas flows great to it.
Still looking for a answer/fix......Thanks

[old1955]

G'day Mike,

This may be a little more accurate.

.040 drilled main air bleed. All E
& G with serial number starting
with D or lower.

.040 replaceable main air bleed.
All E & G with serial number
starting with E or higher.

Instruction 51-1012
9-3-08
is the S&S doco, download that from their site or I'll send it to you.

Have you ever turned off you accelerator pump, tuned it, run all the tests, then started the pump again.
They say the pump can mask incorrect adjustments and jettings.

I guess your manifold is bubble checked, right?

All I can suggest is start at the beginning again, read the doco first, twice may be.

You'll get it fixed!
Pete

[Motorcyclemike]

Problem Solved !

When i re jetted last month i also readjusted the float and i had it reset to low....causing the lean mid range condition....i set it according to the book......and took that Pan for a ride tonight.......got UP the 50 great..smooth..to..60 and 70 great......No__50 to 60mphs____flat spot!
Thanks for all the tips and advice too.
MCM