EvilCartman

iTrader: (1)

Sold my Speed Demon 750 a week ago to a friend that needed one for a project so I (hopefully) upgraded to an 850 Mighty Demon ordered from cnc-motorsports.com The Speed Demon was an earlier model before the EZ adjust baseplate and from what I could tell right away, it had a little better quality control. The new 850 had chips still inside the fuel bowls and flashing around spots where it had been milled.

Cleaned out what I could see, put it on the engine and got fuel to it for leak checking. Secondary side had fuel driping from the boosters so I took the needle and seat out. Uppon doing that, the o-ring came out in two bits Replaced that and cleaned more junk from the area. Did the same to the front just incase and the o-ring was fine, just a little more junk cleaned out.

All leaks stopped, pump arms adjusted, fuel coming out of the squirters, throttle blades set and idle mix screws, turned the engine over and fired right up Set the idle speed and played with the throttle a bit. Dang thing seems to have a lot crisper response than my old carb. Didn't have the chance to drive it since it was 10pm and the car is too loud for around town. Kinda nervous now since tomorrow I'm heading to the track to try out this un-driven carb Other than the minor quality issues, I'm pleased with the carb so far. Just have to wait and see how it performs tomorrow

Damon

That's very disappointing- people have been reporting these types of issues with Demon cars for several years now. I think for the money they charge for these carbs you should expect that these kind of quality control issues would be under better control after all this time. Imagine if you hadn't taken the time to disassemble and inspect for this before you turned the key. You'd probably be another person posting about "why won't my new Demon idle/run right?"

Glad to hear you got it sorted out and good luck with the larger carb.

EvilCartman

iTrader: (1)

Just got back from the track and it's slowly coming around. First run it was pig rich with the stock jetting but I wanted to get a baseline anyway. Picked up 5 mph by the end of the night but ran into a baaaaaad lean spot at the hit of the throttle. So bad the engine goes quiet soon as you punch it. Well the stock squirter's spray pattern was so bad it was shooting right over the booster to the opposite side of the venturie. I had some tube style squirters with me so I changed it out to one of them. Got rid of that problem but it's still pretty sluggish off the line. Next thing I'm going to try is changing the pump cam out. All in all, it wasn't a bad night since I knew going in that I'd be working on it constantly.

JohnnyGTA

im running into the same problems with my mighty demon 850.....from idle to punching it, the damn thing will nearly die and come back to life. I havent touched this carb much but most people say that I need to put in bigger squirters, so im going to try that in the next few weeks. Does changing the squirter size affect the jetting at all? Im new to the carb game but im using a wide band o2 to monitor a/f ratio and with the 85 and 93 size jets the a/f was at 12.1 the other day and i changed to 84 and 92 but i forgot to record that run.

EvilCartman

iTrader: (1)

The squirters are only going to effect things when you punch it or any time you press the throttle down so no, they don't really effect jetting. I stepped up to a 35 tube style squirter in the front just to get the fuel going into the right spot and it helped a lot. Still seems to need more fuel delivered in a shorter time which is where changing the pump cam will come in to play along with the bigger squirter. Here's a video from one of my runs, you can see how lazy the thing was off the line.