The WebCam 91 is:
- valve lift - 0.450 for both I and E.
Duration is - 260 for both I and E.
Duration @ 0.050 - 238 for both I and E.
Lobe center - 108 for I and 111 for E.
Intake opens 11 BTDC / closes 47 ABDC
Exhaust opens 50 BBDC / closes 8 ATDC
I have tried to get the engine to idle with the first progression hole covered by the throttle plate and it won't do it. Even with the mixture screws backed out 1 to 1.5 turns. The engine rocks a whole lot and to the point it sloshes fuel out the main venturie into the carb bore. To get a half way smooth idle, I have to screw down the idle speed screws to just open the first progression hole and the mixture screws either seated or 1/8 turn out. This is with timing at 15 and idle at 1K rpm.
With 50F8 the hesitation is minimal. I tried 50F4 and 50F2 and the hesitation is much worse. If it put in 50F9 the hesitation is gone, but it is way too rich at idle.
So the current setup is:
- 33mm venturie
50F8 idle jet
140 main with 190 air on F16 emul tube
45 accel pump jet
medium weight accel pump spring
accel pump duration is 14mm.
55 pump exhaust valve.
I did a compression check with a warm engine and got 170 on 2,3 and 4 and 172 on 1. So the compression is good.