Anyone have any experience with a MAP 76-Degree Offset, Stroker Billet Crankshaft in a unit-construction Triumph?
According to the MAP website, " The 76-degree crankshaft allows one piston to be at top dead center while the other piston is just reaching it's maximum velocity. This offers the smoothest possible motion in the crank and eliminates much of the vibration in the Triumph twin."
and
it fits:
"All Triumph 650-750cc Twins built after June 1971 (GE27209) though 1983 with metric timing side main bearing. Can be adapted to earlier 650cc twins (see below)"
Specifications:
89mm stroke
1-3/4" journal (use with Norton Rod Bearings)
Approximately 22 pounds
See more here: http://www.mapcycle.com/performance-...ee-offset.html
Stock unit-construction 650 / 750 stroke is 82 mm, so this a 7 mm longer stroke.
Using the engine displacement calculator (http://www.revetec.com/Calculators/E...ulator-2.htm):
71mm x 82mm = 649.3 cc (stock 650)
71mm x 89mm = 704.7cc
76mm x 82mm = 744cc (stock 750)
76mm x 89mm = 807.5cc
It's interesting, but definitely not cheap at $1,950.00 + Rods at $450 + cams at $450 + ignition at $350
Anyone have experience with other stroker cranks in a unit-construction Triumph?
According to the MAP website, " The 76-degree crankshaft allows one piston to be at top dead center while the other piston is just reaching it's maximum velocity. This offers the smoothest possible motion in the crank and eliminates much of the vibration in the Triumph twin."
and
it fits:
"All Triumph 650-750cc Twins built after June 1971 (GE27209) though 1983 with metric timing side main bearing. Can be adapted to earlier 650cc twins (see below)"
Specifications:
89mm stroke
1-3/4" journal (use with Norton Rod Bearings)
Approximately 22 pounds
See more here: http://www.mapcycle.com/performance-...ee-offset.html
Stock unit-construction 650 / 750 stroke is 82 mm, so this a 7 mm longer stroke.
Using the engine displacement calculator (http://www.revetec.com/Calculators/E...ulator-2.htm):
71mm x 82mm = 649.3 cc (stock 650)
71mm x 89mm = 704.7cc
76mm x 82mm = 744cc (stock 750)
76mm x 89mm = 807.5cc
It's interesting, but definitely not cheap at $1,950.00 + Rods at $450 + cams at $450 + ignition at $350
Anyone have experience with other stroker cranks in a unit-construction Triumph?
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