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Superkarts! USA
Motori Seven TAG engine clarifications
Friday, 13 November 2009 18:26
We have had a number of questions about the PDF on Motori Seven engines; following are corrections and clarifications.  Note that these corrections/clarifications reflect no changes to the engine, only corrections to the PDF.

The most common issue is the pipe.  The “A” dimension is listed in the PDF as 105mm.  Pipes in use measure correctly in all other stated dimensions; however the “A” dimension is 115mm.

I have measured 7 pipes that all measured 115mm.  My conclusion is that the pipes were always incorrect according to the PDF in the “A” measurement but were the same in all other dimensions.  I obtained a copy of the PDF submitted by the original Michigan-based importer in 2005 which shows the 105mm dimension to further validate this conclusion. Pictures and actual measurements taken at the TAG workgroup meeting in Chicago in 2007 on the submitted exhaust also show the dimension as 115mm.  Because of this, and based on communications from the manufacturer we are changing the “A” dimension to the correct dimension of 115mm.

Basically we have had a number of issues with errors on the PDF which have been corrected when discovered.

In addition other recent questions that have arisen and their resolution are as follows:
  • Only the PVL ignition is allowed.
  • Stator has been supplied with both cloth wrapped and potted coils.  Both are legal.
  • Coil has been supplied with both red and black coils, both are legal.  Part numbers are:
    • Red:  500.178
    • Black: 105.458
  • Drawing of cylinder development does not contain tolerances.  Correct tolerance is plus 1mm, minus 2mm.
  • Drawing of cylinder development:  correct C1 dimension is 22.7mm
  • Cylinders supplied by the manufacturer recently have been coming with a yellow Motori Seven sticker instead of the cast logo.
  • Clutch drawing is incorrect.  The triangular stamped plate is not present on the clutch.
  • Crankshaft weight should be Kg 2,430 Tolerance +/-  100gram
  • Exhaust dimension “A” is 115mm.  Tolerances are up to 25mm +/- 1mm; from 25 to 60mm +/- 1.5mm; more than 60mm +/-3mm.
Keep in mind that SKUSA reserves the right to adjust weights at any time to equalize competition between engine brands.
John Motley, National Technical Director
SuperKarts! U.S.A.
Last Updated on Wednesday, 10 March 2010 16:31