From: Snag_one@msn.com   
      
   On 2/8/2026 2:32 PM, Bob La Londe wrote:   
   > 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?   
   >   
   >   
   >   
   >   
      
     I like the jack shaft idea . Gives you a LOT of latitude for gearing .   
   Will you really need to alter the height if that axle sprocket is smaller ?   
     I'm getting the ATV I got from a neighbor ready for firewood   
   harvesting duty . It's no bigger than the JD 317 yard tractor and it's   
   much more nimble . I've got the racks front and rear plus a receiver   
   hitch so I can take my big trailer close then use the little one to   
   ferry the rounds out of the woods .   
   --   
   Snag   
      I appreciated foreign cultures more   
   when they stayed foreign ...   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)