Hi guys, I have some dorky questions about tuning with my Demon carb. Borrowed a friends LM2 and am messing around.
I pretty much have A/F and drivability where I want it, but still one thing really bugs me.
This is the setup I got from the guy that converted it to E85
97 main front, 108 rear 6.5 PV
IFR .053
IAB .030
Can't remember off hand HSAB, something in the .030's, but high speed seems good,
approx. .020 of transfer slot is showing at idle
50cc pump (primary)
Race Demon RS w/975 cfm sleeves
Idle mixture screws out 3/4 turn
This thing ran way too rich in the idle circuit with that setup,(and during cruise) so this is what I changed,
IFR .036
IAB .065
Much better and it runs nice and clean at idle, (doesn't load up) and during cruise at approx. 9.5 A/F
Idle mixture screws are out 1 3/4 turns.
Here's my problem,
As soon as I start letting the clutch out, it stumbles. (lean) If I turn out the idle mixture screws out to 2 3/4 turns, it is eliminated, pulls out real nice stumble free. But then it's running to rich at idle and during cruise (approx. 8.0-8.3) and burbling.
It also did the same thing when running with the original setup as recieved. The thing ran pig rich, but when you let the clutch out, it stumbled, and you could see the lean spot on the meter. As soon as you opened up the idle mixture screws, it went away, but then it was really rich, like about 7.5A/F. I don't get it. I don't think this has anything to do with the accelerator pump because if I just start to tip in the throttle and hold it there, and then start releasing the clutch,it will stumble, unless you go up to approx. 2500 rpm.
Which way should I go?
It seems as though this thing really wants fuel when there is a load, but it really wants to be lean during idle and cruise when there is no load.
Here are some engine specs,
522 c.i.
Indy EZ's by MCH
252/260 @.050 hyd. roller .600 lift in&ex
12.6:1 comp
69 Coronet R/T 4-speed w/4.10's
Let me know if you guys need any more info, sorry this is so long
Thanks!

For some reason?, Demon transfer/transition circuit seem too be lean.

If you have the time, separate the main body from the base plate. on many of the demons I have seen, the transfer slots have little pieces of bent spring metal placed in each of the four transfer slots? Why these are not machined into the base plate, I don't know?

The only thing that has worked for me with demons, are super large squirter sizes..050"-.060"


Also the new idle air bleed size .030" seems very small.

Last thought is enough ignition timing?

I looked, and the guy never changed sqirter size, it's still at the stock 31. Maybe it wants more squirter right at tip in? I guess I can try that. Forgot to mention fuel level is halfway up sight glass now, I did try it at the low level, no difference.
Timing is set at 36 total, 18 initial, all in by 2100 rpmish. I only have .036 quench, so I don't think it will want tons of timing, I played with it a little bit, no real differences.
The new IAB is at .065.
The new IFR is at .036, which really cleaned up idle and cruise.
So should I take these little pieces of meteal out of the transfer slots?
Thanks.

The IAB in the 60's sounds alot more normal for E85 than the 30's (not for anything!). I would recommend you talk to DragChevette on www.e85forum.com
He has done a lot of work with E85 and Demon carbs.

did you ever try with IAB size between 0.03-0.065?
I would try around 0.05.