From: none@none.com99   
      
   I pulled one of the kids old yard karts around on the slab behind the   
   shop.  My thought was to get it running again to be used as a rolling   
   speed bump.   
      
   The carb was shot, it has terrible ground clearnace, and my other   
   solutions lead me to wanting to put an easy to ready analog tach on it.   
      
   Here is where my thought process is so far.   
      
   Intruder II 7hp Subaru EX21   
      
   Mostly about the EX21.  I'm getting ready to swap over VM22 style carbs   
   with high flow muffler on straight header, and there is no way to   
   connect the governor.  This is background only.  Not seeking feedback on   
   that.   
      
   The engines are actually very low hours.  We never let the kids run the   
   karts unsupervised.   
      
   Looking to connect reasonably large tach to engine.  These engines do   
   have a lighting circuit, but maybe not a proper charging system (dual   
   front lights on cart).   
      
   Looking at the cheap import CX8150 Tachometer.  It looks like I might   
   just be able to wrap the signal wire around the spark plug wire and get   
   enough induction to trigger the tach.  I am wondering about powering the   
   tach.   
      
   1.  I'm not above just putting a couple 6 or 9 volt alkaline batteries   
   in series to power the tach (and gps speedometer), but does the unit   
   require a common ground with the engine?   
      
   2.  What exactly is the lighting circuit putting out?  Could I power the   
   tach from that?  The tach says the power input is 9-72VDC, but if the   
   lighting circuit is unregulated AC that could be an issue.   
   Kids driving could easily over rev, but my kids are not kids anymore,   
   and I learned to drive by the tach myself growing up.   
      
   Yes, I know heavier springs will reduce valve float, but then you need a   
   better CAM to reduce CAM wear, then you actually start to need a billet   
   fly wheel and connecting rod to prevent the engine from coming apart at   
   higher RPM, etc, etc, etc...  I think the easy answer is to just keep an   
   eye on the TACH and if it blows it blows.   
      
   Intruder II Ground Clearance   
      
   The Intruder II karts have only a few inches ground clearance under the   
   axle sprocket.  It's pretty well designed for fun speed and   
   acceleration, but its more a yard kart as configured than an OHV kart.   
   I'd like to get more ground clearance.  Larger tires only works if you   
   increase power or change the gearing.  Changing the gearing generally   
   means a larger sprocket on the axle which takes back some of that ground   
   clearance.   
      
   I was thinking maybe add an intermediate jack shaft between the CVT and   
   the axle.  Turn the CVT up and my own back plate out of heavier aluminum   
   plate.  I have plenty on hand I make aluminum molds.  Then drive an   
   intermediate jack shaft with the CVT and axle sprockets, and got with a   
   much smaller one to one sprocket from the jack shaft to the axle.  This   
   gives me even more room to play with gearing if need be, and any ground   
   clearance from moving the suspension or increasing tire size is actually   
   available.   
      
   I know at that level of fabrication its "almost" worth just building a   
   purpose built kart, but not quite.   
      
   I'm pretty sure there will be some loss from the extra drive hardware,   
   but I am already improving engine air flow with a VM22 style carb and a   
   header.  I'm not looking to change it from a 25-30MPH kart into a 40 MPH   
   kart.  I am looking at getting more ground clearance at about the same   
   speed.   
      
   What am I missing?   
      
      
      
      
   --   
   Bob La Londe   
   CNC Molds N Stuff   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)