Class help

[mhuppertz]

We want to prep a Honda CT90 for a run at speed week. Can anyone help me with class designation? it will be under 100cc (5.5 ci), run in stock body form naturally aspirated or superchareged.
Thanks!
Mark

[Stan Back]

Got a Rule Book?  The answer (along with a lot of other things you need to know) is probably there.  See the SCTA-BNI.org website.

[desotoman]

CT90 isn't that the designation for a Honda Trail 90? The motor has an OHC so in stock form normally aspirated you would run in 100cc P-P. Current record at Bonneville for 100cc P-P, is held by Katy Gassaway, type of bike is a Derbi, date record set 8/03, Record is 82.846 mph. Hope this helps.

Tom G.

[McRat]

That is curious.  The 100cc P-PP (Production chassis, production pushrod engine) record says Honda.

When did Honda make a pushrod minibike engine?

If I were hunting a production powerplant for a 100cc bike, I'd look at either the Suzuki or Kawasaki rotary valve two strokes.  With the right massaging, you can make some pretty good high RPM power with a rotary valve.

[desotoman]

That is curious.  The 100cc P-PP (Production chassis, production pushrod engine) record says Honda.

When did Honda make a pushrod minibike engine?

The 87cc PUSHROD HONDA C200 1964.

Tom G.

[McRat]

Huh.  Looks just the OHC engine.  IIRC, my 305cc Honda Scrambler was OHC, and 1963-64'ish.  It had centifugal spark advance and a centifugal oil filter.  I'll admit I never paid a bunch of attention to the Honda 90's and their kin.