koko64
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« on: March 01, 2019, 04:36:22 AM » |
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A good mate and I compared our similar but different motors in our bikes, my M900 and his 944 Superlight (1992 No 173). We have compared the bikes before but they have evolved. 944SL 94mm JEs Porting FCR39"s DP flywheel approximately 700gms Extended open airbox, ported v stacks 900ie cams Ignitech Dyna coils Steel clutch basket and plates Straight mufflers
M900 JE hi comps Porting FCR41's Dialled stock V cams 6 deg adv ala bikeboy Extended open airbox, ported V stacks Stock flywheel Ignitech Exactfit coils Alloy clutch basket and plates Straight mufflers
We worked on the SL as it hadn't been started in a year. The neglected Shorai battery started it first attempt, no trickle charger or top up charge in a year. Nothin'. ---------
Our test run included the outer suburban streets leading to Mt Dandenong with its Tourist Rd and Old Mountain Hwy of Mt Dandenong. We swapped bikes back and forth and exchanged thoughts over espresso.
One thing we noted was at ten years older I no longer could tolerate light flywheels from a comfort perspective while loving the acceleration. The DP flywheel in the SL is not excessively light but the visceral edge was very apparent to me. Me mate just thought the Monster was smooth.
-------- As I expected there was more immediate throttle response at smaller throttle openings with the FCR39's, but only at part throttle transitions. Maybe the fkywheel response was masking the feel, so it was not really a direct comparison there. I also could not feel much difference in low rpm torque between the 944 and 904 motors but it was probably the difference in cams evening that out. Dyno charts show that there can be anywhere between 4-8 ft/lbs of extra torque from 944 JE pistons over the 904 JE's. I reference Doug Lofgren and JD Hord in that comment. I think Brad Black's cam specs on the 900V cams help bridge that gap with my 900 verses the 944 having ie cams pushing the torque up the rev range a little.
It will be fun doing further testing.
A point that came out of post ride discussion was that me mate liked the feel of heavy clutch components and a lighter flywheel while I preferred the feel of the stock flywheel and the lightest clutch components possible. I'm still thinking through what that means exactly.
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