100cc forced induction F4 bucket. Anyone keen to have a real go?

[husaberg]

Oldie but still interesting.......

[Brian d marge]

not sure if this is of any help but Ill stick it up here ( was clearing out old docs )


On the other hand, if the camshaft is retarded, the intake valve will close later (usually sometime during the compression stroke). As you might expect, this drops cranking compression and hurts low-rpm power. But as rpm increases and cylinder filling is aided by the extreme velocity of the air/fuel charge in the ports, a retarded camshaft will help power. Usually, the change-either advancing or retarding-should be less than eight degrees. If you need to go more than that you should consider using a different cam.


and
intake exhaust
open closes opens closes lift measured tappet
btdc abdc bbdc atdc intake exhaust clearance radius
650cc 34 55 55 34 0.002
6T DU.101 on 25 52 60 17 0.305 0.305 0.020
TR6 DU.101 to DU.44393 34 55 48 27 0.314 0.296 0.020
T120 DU.101 to DU.24874 34 55 48 27 0.314 0.296 0.020 0.750
T120 DU.24875 to DU.44393 34 55 55 34 0.314 0.314 0.020
T100S 34 55 48 27 0.296 0.020 0.750
T100T 40 52 61 31 0.314 0.314 0.020 1.125
5TA to H.49833 34 44 48 27 0.020
TR5T 34 55 48 27 0.020 0.750
T100R 40 52 61 31 0.020 1.125
Triumph 750 short rod 26.5 69.5 61.5 35.5 0.350 0.350 0.020 1.125 ? What cam ?
Triumph 750 intake (T-75) 40 74 0.345 0.020 1.125 Matches M20416 T140E intake
Jomo 15 43 74 74 43 0.355 0.355 0.020 1.125

Advancing
the cam timing moves the valve opening and closing events earlier in
the cycle. Since the relationship between the intake and exhaust lobes
cannot be changed, advancing or retarding a cam affects both the intake
and exhaust valve equally. Also, the most important thing advancing or
retarding a camshaft affects for engine power is when it closes the
intake valve. For example, if the camshaft is advanced, the intake
valve closes sooner. This typically increases cranking compression on a
high-duration race cam. The result is more torque and power in the
lower rpm ranges. But as the rpms increase, the velocity of the
air/fuel charge in the intake ports also increases dramatically and the
early intake valve closing hurts power.


Stephen

[husaberg]

not sure if this is of any help but Ill stick it up here ( was clearing out old docs )


Stephen

Thanks

I have a real neat article that works with the cam timing and how it moves the spread an the power peak of the old Suzuki oil pumpers somewhere.