Exactly, it bucked like a **** under 3 wide open (I don't even know why you would ride a thumper so low? By the time I let me clutch out in first 10mph is 4k rpm), but at 3-4k rpm cruising I'm getting 70 miles per gallon! It doesn't seem to get too hot, runs fine, and pulls hard, I'm pretty rich on the main so I think I'll go down on it, but bedsides that leave it pretty much where it is.

 

Your dipping into the upper 11's at the upper end of the RPM range. Your 12:1 at peak power.
Those numbers are rich - Too rich IMO.

The funky lean numbers are likely due to the operators' handling of the throttle. The pumper carb makes low RPM transitions to WOT difficult to perform - He probably babied the throttle too much trying to get a smooth transition - sound about right?

 

Those numbers are proof of the huge benefit of running the 351 with the TM36, stock header, loud slip-on, and no lid...

Incredible!

 

Nah he was just sitting then snapped wide open. It doesnt bother me too much, when aroud town the snap is more than adequent for me.

The leaner main should make more power for sure, 1hp worth? Mayhaps...one can hope. My next ru is free so whatever I tweak i'll throw up another run

 

12-1 at peak power is pretty close to ideal. You don't want to go any leaner than 13-1 unless it's at cruise.

 

just remember that these readings are taken at full throttle so they only reflect on the main jet system- You would need to do pulls at varying throttle settings to get an accurate picture of how the carb is metering across the board.

 

How bout it GBAUTO, Dyno run ? I'm wondering if those 101's and larger I.D. FMF system puts you well over 30HP...?

 

We did, i just don't have the charts for those runs because they were short and more for personal knowledge.

Holding at 8k rpm showed 10:1 AFR spike( my trouble area, likes to cut out when riding hard), mid range varied from 13:1 to 14.5.1, and idle was about 13.4:1, 4k rpm showed 16:1 I think

 

Perhaps your carb set up is spot on Matt. This is an exerpt from AFR theory: Maximizing Torque (and thereby Power) - NASIOC



14.68:1 (~14.7:1) Stoichiometric mix
12.8:1 - Lean best torque
12.2:1 - Mean best torque
11.76:1 - Rich best torque
11.01:1 - Fastest flame speed in cylinder

All five ratios are directly from Hartman's book.

He argues that "at a very minimum you are aiming for mean best torque" or 12.2 AFR, "if not rich best torque" at 11.76 AFR. 11.76 AFR has a side benefit of higher cylinder flame speed.

Torque starts dropping off the moment you start to go richer than Mean Best Torque and begins to drop off dramatically after Rich Best Torque. Counter-intuitively the Fastest Flame Speed at 11.01:1 AFR does not produce the most torque, but there is a cliff-like drop off in torque when you start to go richer than that point.

To sum up, Hartman states that 11.76 AFR is the richest one should shoot for. You may have to tune back the boost to get there but you'll get the same torque with better fuel usage than if you turned the boost up and went crazy rich (e.g. 10.8:1).


I settled on a 12.8:1 target after researching.. What do you say Woof?

 

It'll run much cooler being rich as it is at wide open, the problem is it'll cut out from ebing so rich and on the dyno start to burble. I say those guys who hashed out jetting had it pretty spot on, their needle, jet needle, and pilot settings were very good